Worksheet- Mutations

Biology

At Home Learning Packet Biology Daily Assignments

Day 1 Read BIO 1A Life and Organization and answer questions 1-12 on BIO 1A

Day 2 Read BIO 1A Life and Organization (same as first day) and answer questions 13-24

Day 3 Work BIO 1A Cell Theory Time Line and Cell Theory Student worksheets

Day 4 Work BIO 1A.3 Cell Organization Guided and Independent Practice worksheets

Day 5 Read BIO 1B.1 Macromolecules and answer questions 1-15 on BIO 1B.1

Day 6 Read BIO 1B.2 Enzymes and answer questions 1-15 on BIO 1B.2

Day 7 Work BIO 1B Biomolecule and Enzyme Independent Practice sheets

Day 8 Read BIO 1C.1 Function of Organelles and answer questions 1-16 on BIO 1C.1

Day 9 Read BIO 1C.2 Eukaryotes and Prokaryotes and answer questions 1-12 on BIO 1C.2

Day 10 Work Prokaryotic and Eukaryotic Guided and Independent Practice questions- Use words from activity cards to fill in Venn diagram

Day 11 Read BIO 1C.3 Viruses and answer questions 1-15 on BIO 1C.3

Day 12 Read “Virus” reading passage and answer questions and work Virus Independent Practice sheets

Day 13 Read BIO 1D Cell Transport and answer questions 1-18 on BIO 1D

Day 14 Read BIO 1E Cell Cycle and answer questions 1-20 on BIO 1E

Day 15 Read BIO 1E Cell Cycle ( same as previous day) and answer questions 21-40 on BIO 1E

Day 16 Work BIO 1E Cell Cycle Independent Practice and Read and answer questions for BIO 1E Reading “Frogs and You”

Day 17 Read BIO 3A Meiosis and answer questions 1-20 on BIO 3A1 Meiosis questions sheet

Day 18 Read BIO 3A Meiosis( same reading as previous day) and answer questions 1-18 on BIO 3A2&3 questions sheet

Day 19 Work BIO 3A Meiosis Guided and Independent Practice sheets and BIO 3A Mitosis/Meiosis Crossword Puzzle

Day 20 Read BIO 3B 1&2 Mendel and Genetics and answer questions 1-20 On BIO 3B 1&2

Day 21 Read BIO 3B 3&4 Patterns of Inheritance and answer questions 1-20 On BIO 3b 3&4

Day 22 Work BIO3B Vocabulary Square , BIO 3B Student Worksheet and BIO 3B Mendel Independent Practice sheet

Day 23 Read BIO 3C 1&2 Genetic Material and answer questions 1-15 on BIO 3C 1&2

Day 24 Read BIO 3C 1&2 Genetic Material and answer questions 16-30 On BIO 3C 1&2

Day 25 Work BIO3C DNA Guided Practice ,Independent Practice, and Vocabulary Triangle (Cut apart, mix up and correctly match the word to its definition or to its complementary pair. It will form a triangle. When a student has used all the pieces to form a large triangle, have the teacher check the answers.)

Day 26 Read BIO 3C 3 Gene Mutations and answer questions 1-20 on BIO 3C 3

Day 27 Work BIO 3C Mutations Worksheet

Day 28 Read BIO 3C 4&5 DNA Technology and answer questions 1-20 on BIO 3C 4&5

BIO 1A. Living Organisms & Viruses Living things share certain characteristics in common. Being able to reproduce and use resources for energy are two of those characteristics. In the past, scientists have considered viruses to be nonliving. New research, however, is challenging that idea. Characteristics of Life

There are several characteristics that all types of organisms on Earth have in common. These characteristics determine whether something is considered a living organism or is nonliving.

1. Organisms are made of cells.

Cells are the basic unit of life. All organisms are composed of one or more cells.

2. Organisms grow and develop.

Growth and development are processes that increase an organism's overall size and lead to an increase in the complexity of the structure of an organism. Development continues from infancy to childhood, and on through adulthood.

3. Organisms obtain and use resources for energy.

Organisms need energy in order to perform basic life processes, such as growth, development, and repair. Organisms that make their own food, such as through photosynthesis, are autotrophs. Organisms that obtain food from the environment are heterotrophs.

4. Organisms are able to respond to stimuli in their environment.

All organisms can recognize changes in their internal and external environments and respond to them. For example, plants detect light and bend toward it.

5. Organisms maintain homeostasis.

By regulating their internal environment to maintain a constant state, organisms maintain homeostasis. For example, when a person's internal temperature is too high, the body begins to sweat in order to reduce the temperature through evaporation.

6. Organisms are capable of passing on genetic material through reproduction.

All organisms are able to reproduce in order to ensure that their species lives on.

7. Organisms adapt.

Adaptation is the ability to change over time in response to the environment. Through adapation, species evolve to better fit their environment. Viruses vs. Cells

A virus is an infectious agent that is only able to replicate inside the living cells of another organism. A virus consists of genetic material (either DNA or RNA) surrounded by a protein coat. Viruses are the most abundant biological entity on Earth—viruses are diverse, ranging in size and shape, and are specialized to infect all different forms of life, from archaea to animals.

While viruses and cells have some features in common, there are several major differences that distinguish viruses from cells.

Characteristics of Cells • Cells are alive, and they are the basic units of all life. • Cells can reproduce on their own. • Cells possess organelles and ribosomes. • Cells have their own energy metabolism. • Cells are surrounded by a cell membrane. • Cells are much larger than viruses.

Characteristics of Viruses • Viruses are generally considered to not be alive. • Viruses must use a host cell to reproduce. • Viruses do not possess organelles or ribosomes. • Viruses do not have their own energy metabolism. • Viruses are surrounded by a protein coat. • Viruses are extraordinarily small.

Characteristics of Both Cells & Viruses • Both cells and viruses contain some form of nucleic aid (DNA or RNA). • Both cells and viruses can infect host cells. Are Viruses Living Organisms?

Most scientists have historically considered viruses to be nonliving. However, some scientists are reconsidering this classification. One reason why viruses are generally considered not living is that they require other organisms to reproduce. However, there are many organisms, like some types of bacteria and fungi, that are obligate parasites. This means they cannot complete their life cycle without a host. Another traditional justification for classifying viruses as nonliving is that they do not have the proteins needed to replicate themselves. However, giant viruses discovered in the 2000s do have genes that code for most of these proteins, though the viruses still use host cells to replicate. Evidence also suggests that viruses have many unique genes, rather than simply copies of genetic material from a variety of cells. These points have scientists rethinking if viruses should be classified as living organisms.

Cell Theory

Cell theory was developed over time using contributions from a number of different scientists. It states that cells are the fundamental units of life. Major Tenets Cell theory is one of the foundations of biology. There are three major tenets of the cell theory: • Cells are the most basic structural and functional unit of life. • All organisms are composed of one or more cells. • All cells that currently exist came from pre-existing cells. History of the Microscope and the Cell

The microscope played a pivotal role in the development of cell theory. Born in 1635 in England, Robert Hooke contributed to many different fields of science and technology. He built a compound microscope— a microscope that used two lenses. With this, Hooke became the first to observe what he would later name cells. He published his observations in 1665 in the popular book Micrographia.

This image of cork cells is taken from Micrographia by Robert Hooke. Anton van Leeuwenhoek, born in Holland in 1632, was a contemporary of Robert Hooke. The Dutch scientist became very skilled at grinding lenses and was able to build simple microscopes that could magnify objects up to 200 times while still giving a clear image. Because of this, van Leeuwenhoek is considered by many to be the father of microscopy.

Though the first microscopes were invented in the previous century, van Leeuwenhoek's models were such a vast improvement over earlier microscopes that some people attribute the invention of the microscope to him. He was the first to observe and describe bacteria as well as protists. A replica of one of Leeuwenhoek's microscopes is shown below.

Image courtesy of Jeroen Rouwkema via Wikimedia Commons under CC BY-SA 3.0. Further Contributions to Cell Theory

Cell theory was gradually developed over time by many different scientists. The timeline shown below lists some of the scientists that contributed to the cell theory.

In the late 1830's, two scientists - Theodor Schwann and Matthias Jakob Schleiden - formally proposed the first two statements in the theory, but they also erroneously thought that cells arose through spontaneous generation.

In 1855, another German scientist named Rudolf Virchow observed cells dividing to produce new cells. Based on his observations, Virchow proposed that all cells were the product of cell division. With this modification, cell theory became widely accepted.

Since then, various studies have only slightly altered the original theory. Biochemical research has provided more information into cellular chemistry and phylogeny. This research not only supports the original tenets of the theory, but expands upon them. Such additions to the theory include: • The hereditary information of a cell, which is contained within its DNA, is passed to daughter cells during cell division. • The chemical composition of similar cells within similar species is basically the same. • All cells require energy and have ways of obtaining and using it. • All cells have ways of eliminating waste.

Cell Organization

All living things are made of one or more cells. Cells are the basic building blocks of all organisms.

Organisms with only one cell are known as single-celled, or unicellular, organisms. Organisms with more than one cell are known as multi-celled, or multicellular, organisms.

The organization of cells into complex structures allows for the wide variety of life found in multicellular organisms. Unicellular and Multicellular Organisms

Simple organisms, such as amoeba, are made of only one cell. These organisms are known as unicellular, or single-celled, organisms. All of a unicellular organism's life processes occur in its one cell.

More complex organisms, such as plants and animals, are made of many cells. These organisms are known as multicellular, or multi-celled, organisms. There are many different kinds of cells in multicellular organisms. Often, these cells have different sizes and shapes because they perform different functions.

Organization in Multicellular Organisms

Multicellular organisms exhibit a hierarchy of cellular organization. They are complex in that there is a division of labor among this hierarchy for carrying out necessary life processes.

From simplest to most complex, the proper levels of organization in multicellular organisms are:

The levels of biological organization in order from smallest to largest are: organelle → cell → tissue → organ → organ system → whole organism. Organelles

Organelles are specialized subunits in the cell. Organelles are usually enclosed in their own lipid membrane, and they each have their own specific function. There are many types of organelles, such as ribosomes, nuclei, mitochondria, and chloroplasts. Cells

Cells are the structural and functional units of all living organisms. Organisms can be made up of one cell or many cells. Cells contain the genetic information of an organism, and some cells contain organelles. In multicellular organisms, cells specialize depending upon where they are located within the body. All cells come from other cells, and they divide by mitosis or meiosis. Tissues

Tissues are composed of many cells that work together to perform a specific function. Tissue covers most parts of an organism. There are several types of tissues, including connective tissue, muscle tissue, nervous tissue, and epithelial tissue. Organs

Organs are composed of several tissues and perform one or more functions in the body. In most organs, there is a unique 'main' type of tissue (such as the myocardium of the heart) and several other tissues that are found in many organs (such as connective tissue). The body is made up of many organs, including the heart, lungs, liver, eyes, and brain. Organ Systems

Organ systems are groups of related organs that work together to perform a function or set of functions. The functions of the various organ systems usually overlap and are influenced by each other. There are eleven major organ systems in the human body, including the respiratory, reproductive, digestive, skeletal, muscular, nervous, circulatory, endocrine, urinary, integumentary, and lymphatic systems. There are two main organ systems in vascular plants—the root system and the shoot system. Whole Organism

The whole organism is composed of all of the various organ systems. An organism's functions are carried out by cooperation between all of the systems.

BIO1A Question 1 .

An organ system is made up of

A. organisms that have similar behaviors and appearances.

B. all of the tissues found in an individual organism.

C. identical cells that perform the same function.

D. organs that work together to perform a certain function.

Question 2 .

In 2018, researchers discovered a new type of virus called the Tupanvirus. They made the following observations about this virus.

Observation 1 Observation 2 Observation 3 contains many of the if taken into a non-host uses amoebas as genes needed to build cell, causes the cell host cells its own proteins and to destroy itself copy its DNA

Information courtesy of Abrahao et al., 2018. Nature Communications. Licensed under CC BY 4.0.

How could this information support the argument that viruses could be living organisms?

A. Observation 2 suggests that viruses may have once had the ability to reproduce outside of a host.

B. Observation 3 shows that viruses must be able to take in and use energy.

C. Observation 2 suggests that viruses are incapable of evolving over time.

D. Observation 3 shows that viruses are unable to respond to and interact with their environments.

Question 3 .

All living organisms use energy. They also grow and reproduce. What is another characteristic of all living organisms?

A. All living organisms can produce glucose through photosynthesis.

B. All living organisms are composed of one or more cells.

C. All living organisms consist of many cells with specialized organelles.

D. All living organisms must consume food in order to acquire nutrition.

Theodor Schwann is considered one of the founders of cell theory. What is one way that Theodor Schwann contributed to the development of cell theory?

A. He was the first to propose that cells only arise from pre-existing cells.

B. He determined that all animals are made up of cells, which helped lead to the conclusion that the cell is the basic unit of life.

C. He determined that all plants are made up of cells, which helped lead to the conclusion that all living organisms are made up of cells.

D. He was the first to observe and describe a cell using a microscope.

Question 5 .

A virus can be considered nonliving, even though it is capable of invading and destroying living organisms. Which of the following is a reason that a virus can be considered nonliving?

A. Viruses can only reproduce through fission.

B. Viruses only metabolize inorganic minerals.

C. Viruses are not able to grow.

D. Viruses are too small to be considered a viable form of life.

Question 6 .

Blood consists of different types of cells—red blood cells, platelets, and white blood cells.

Red blood cells transport oxygen throughout the body, platelets aid in blood clotting, and white blood cells help destroy and remove old cells and foreign substances.

This is an example of how

A. different cells are unable to be grouped together within the same organ or organ system.

B. only similar cells are grouped together so they can perform a singular function.

C. the cells of the body are of different kinds and are grouped in ways that enhance how they function together.

D. every part of the body contains different cells with unique and unrelated functions.

The picture below shows one cell dividing into two cells.

Which of the following statements is best supported by the picture shown above?

A. All cells come from pre-existing cells.

B. Cell division only occurs in animals.

C. All organisms are multi-cellular.

D. Both living and non-living organisms contain cells.

Question 8 .

In 1987, scientists isolated an unknown biological particle from the sand of a river. The particle had the following characteristics:

is single-celled cannot function in the presence of oxygen has circular DNA uses inorganic substances like metals for energy reproduces without a host cell

Based on the given information, is it likely that the particle is classified as living or nonliving?

A. living, because the particle uses energy and reproduces on its own

B. nonliving, because the particle cannot transmit genetic material to offspring

C. living, because the particle has DNA

D. nonliving, because the particle does not need oxygen or food

Question 9 .

When a group of cells work together, such as in bones, muscles, or nerves, they are known as ______.

A. an organism

B. an organ

C. a tissue

D. an organelle

Directions: Drag the tiles to the correct boxes to complete the pairs.

Diego is comparing the hierarchical organization of his school system to the hierarchical organization of systems within organisms. Match each part of a school system to the part of an organism that shares a similar level of organization.

organ tissue organ system cell

school system

school

class

student

Question 11 .

As Darla is walking along the beach, she encounters something she's never seen before. When she touches the object, it appears to move away from her. This observation makes Darla wonder if the object is alive.

Which of the following positive test results could provide Darla with another piece of evidence that the object is alive?

A. presence of ions

B. presence of water

C. presence of oxygen

D. presence of DNA

Question 12 .

Organisms are made up of structures that allow them to grow, survive, and reproduce. From simplest to most complex, how are the structures organized within organisms?

A. organs → organ systems → cells → cell parts → tissues → organisms

B. tissues → cell parts → cells → organs → organ systems → organisms

C. cells → cell parts → organs → tissues → organ systems → organisms

D. cell parts → cells → tissues → organs → organ systems → organisms

There are many criteria that are used to define living things. Living things reproduce, grow, and develop. They respond to stimuli, use materials and energy, and evolve and adapt over time to their environment. What is another criteria used to define living things?

A. All living things are made of cells.

B. All living things are able to move.

C. All living things are complex.

D. All living things are intelligent.

Question 14 .

Directions: Drag each tile to the correct box.

The levels of organizations in multicellular organisms are shown below, but they are not in the correct order. Arrange the levels of organization in order from simplest to most complex.

organ whole organs cells tissues systems organisms

→ → → →

Question 15 .

______are the basic building blocks of all living organisms.

A. Tissues

B. Cells

C. Organs

D. Organ systems

Question 16 .

What contribution did Robert Hooke make to the development of cell theory?

A. He suggested that all living organisms are made up of cells.

B. He first observed and described cells in plant tissues.

C. He determined that cells can arise spontaneously.

D. He first proposed that cells can only arise from pre-existing cells.

The image below shows an onion root viewed under a microscope.

Which of the three primary tenets of cell theory does this image best demonstrate?

A. All cells contain DNA in their nuclei.

B. Cells of different organisms have similar composition.

C. Living organisms are composed of one or more cells.

D. New cells only arise from pre-existing cells.

Question 18 .

Matthias Schleiden is considered one of the founders of cell theory. What is one way that Matthias Schleiden contributed to the development of cell theory?

A. He determined that all animals are made up of cells, which helped lead to the conclusion that the cell is the basic unit of life.

B. He observed a cell in the process of forming, which led to the conclusion that cells can exhibit spontaneous generation.

C. He observed a cell in the process of dividing, which led to the conclusion that all cells arise from pre-existing cells.

D. He determined that all plants are made up of cells, which helped lead to the conclusion that all living organisms are composed of cells.

Question 19 .

In the 1800s, the work of Rudolf Virchow and others led to third tenet of cell theory. What contribution to cell theory did Rudolf Virchow make?

A. After seeing evidence of photosynthesis, he concluded that energy flow occurs within cells.

B. After observing cells in animals, he concluded that the cell is most basic unit of life.

C. After seeing evidence of cell division, he argued that all cells arise only from pre- existing cells.

D. After observing cells in plants, he concluded that all life is made of one or more cells.

Directions: Select each correct answer. More than one answer may be correct.

Which of the following is a major tenet of the cell theory?

All organisms are composed of one or more cells.

All cells that currently exist have originated from pre-existing cells.

Cells are the most basic structural and functional unit of life.

All cells possess DNA enclosed within a nucleus.

Question 21 .

Which of the following characteristics is shared by all living organisms?

A. an internal circulatory system

B. a method of locomotion

C. the need for oxygen

D. the ability to respond to stimuli

Question 22 .

The advancement of which type of microscope led to the development of the cell theory?

A. compound light microscope

B. dissecting microscope

C. transmission electron microscope

D. scanning electron microscope

Question 23 .

Arteries are tube-like organs of the circulatory system. They have three distinct layers. The middle layer contains smooth muscle tissue, which contracts and relaxes to push blood through the artery. It also contains elastic connective tissue that gives the artery flexibility and helps to regulate blood pressure.

Which statement describes how the tissues in this layer relate to the artery's function?

A. The two tissues are made up of the same types of cells, allowing each tissue to perform all the functions of the artery.

B. The two tissues contain different types of cells, allowing each tissue to perform different functions for the artery.

C. The two tissues contain identical cells, but the shapes of two tissues allow them to perform different functions.

D. The two tissues lack cells, but their position in the middle layer allows each tissue to perform their specific functions.

The National Aeronautics and Space Administration (NASA) is involved in the study of astrobiology, which includes the search for life on other planets. The table below describes the biological definition of life and the NASA definition of life.

Biological Definition NASA Definition

maintains a stable is a chemical system that internal state makes its own proteins made up of one or can reproduce on its own more cells has molecules that carry can break down chemical inherited information compounds for energy has random variations grows and reproduces in chemical structures responds to stimuli evolves through adapts to changes natural selection

If discovered, which would most likely be considered a living organism by the NASA definition but not the biological definition of life?

A. a virus that synthesizes its own proteins and reproduces outside of a host cell

B. a virus that needs to insert its DNA into a host cell in order to reproduce

C. a bacterium that can break down oil and other pollutants instead of sugars for energy

D. a bacterium that can only break down sugar molecules for energy

1. D

2. A

3. B

4. B

5. C

6. C

7. A

8. A

9. C

10. --

11. D

12. D

13. A

14. --

15. B

16. B

17. C

18. D

19. C

20. --

21. D

22. A

23. B

24. A

Cell Theory Timeline 2000 1900 1800 1700 1600 1500

1 Cell Theory

Description Cards

Robert Hooke is the first to use Hans and Zacharias Janssen the term “cells” to describe invent the compound box-like structures of cork microscope. viewed with an early microscope.

Antonie van Leeuwenhoek is The cell theory is developed the first to view living cells, based on 200 years of discovering bacteria and scientific evidence. protozoa.

New discoveries lead to the addition of three new principles to the cell theory, creating the modern cell theory.

All living things are The cell is the basic All cells come from made of cells. unit of life. preexisting cells.

Hereditary All cells are basically information is passed All energy flow of life the same in chemical from cell to cell occurs within cells. composition. during division.

1 Cell Theory

Cell Theory Timeline occurs within cells. All energy flow of life 2000 preexisting cells. All cells come from theory. 1900 composition. All cells are basically the same in chemical addition of three new creating the modern cell principles to the cell theory, New discoveries lead to the unit of life. scientific evidence. The cell is the basic based on 200 years of 1800 The cell theory is developed division. Hereditary information is passed from cell to during

1700 protozoa.

made of cells. All living things are discovering bacteria and the first to view living cells, Antonie van Leeuwenhoek is 1600 microscope. invent the compound Hans and Zacharias Janssen 1500 microscope. viewed with an early box-like structures of cork the term “cells” to describe Robert Hooke is the first to use 1 Cell Theory

Student Worksheet

Answer the questions below.

1. Explain how the microscope was influential in the development of the cell theory. ______

1. How did continuous investigations and new scientific information influence the development of the cell theory? ______

1. What is the cell theory? Fill in the blanks with the words below. Some words may be used multiple times.

Chemical Cell Energy Living Cells Life Division

The Cell Theory

● All ______things are made of ______.

● The ______is the basic unit of ______.

● All cells come from preexisting ______.

● Hereditary information is passed from ______to ______

during ______.

● All cells are basically the same in ______composition.

● All ______flow of life occurs within cells.

1 Cell Theory

Student Worksheet

Answer the questions below.

1. Explain how the microscope was influential in the development of the cell theory. Before the invention of the microscope, it was impossible to see cells. With the invention of the microscope, scientists were able to see a whole new microscopic world. Over time, the quality of the microscope improved, allowing scientists to make better observations of cell structure and function.

1. How did continuous investigations and new scientific information influence the development of the cell theory? The cell theory was based on 200 years of scientific evidence collected from many different scientists. Scientists made new discoveries that were tested using the scientific method by other scientists through the years. Some conclusions about cells were supported by evidence, and some conclusions were found to be invalid. Over time, the collective evidence of cells was culminated in the the cell theory.

1. What is the cell theory? Fill in the blanks with the words below. Some words may be used multiple times.

Chemical Cell Energy Living Cells Life Division

The Cell Theory

● All living things are made of cells.

● The cell is the basic unit of life.

● All cells come from preexisting cells.

● Hereditary information is passed from cell to cell during division.

● All cells are basically the same in chemical composition.

● All energy flow of life occurs within cells.

1 Levels of Organization

Levels of Organization

Answer the questions below.

1. What are the small structures within a cell?

1. What structures make up tissues?

1. List which part of the organization system refers to each example below.

a. a kidney

a. an elephant

a. esophagus, stomach, small intestine, and large intestine working together

a. blood

a. a neuron

2. What is the order of the cards from the most specific to the most general?

5. Create an organism metaphor using the United States as the organism. Fill in the blanks with your own ideas.

If the U.S. were an organism, then one of its organ systems would be______. The organ system is made of organs that function together; ______represents an organ in the United States. Organs are made of tissues; an example of tissue in the U.S. organism would be ______. Cells make up tissues, so an example of a cell in the U.S. organism is ______.

1 Levels of Organization

Levels of Organization, continued

Using all of the following terms in the word bank, complete the graphic organizer.

Word Bank atom cells molecules organisms organ system organs tissues

1.______

two or 3.______more form

basicof unit life 2.______

Organization 4.______smallest Level

hierarchy system for make

5.______6.______

made of function together

7.______

2 Levels of Organization

Levels of Organization

Answer the questions below.

1. What are the small structures within a eukaryotic cell?

Organelles

2. What structures make up tissues?

Cells

3. List which part of the organization system refers to each example below.

a. a kidney Organ b. an elephant Organism c. esophagus, stomach, small intestine, and large intestine working together Organ System d. blood Tissue e. a neuron Cell

4. What is the order of the cards from the most specific to the most general?

Atom→ Molecule→ Organelle→ Cell→ Tissue→ Organ→ Organ System→ Organism→ Population→ Community→ Ecosystem→ Biosphere

5. Create an organism metaphor using the United States as the Organism.

Answers will vary; this is only one possibility: If the U.S. were an organism, then one of its organ systems would be a state. The organ system is made of organs that function together; counties represents an organ in the United States. Organs are made of tissues; an example of tissue in the U.S. organism would be cities. Cells make up tissues, so an example of a cell in the U.S. organism is fire department. Levels of Organization

Levels of Organization, continued

1. atoms

two or 3. cells more form

basicof unit life 2. molecules

Many Organization 4. tissues Molecules Level

hierarchy system for make

5. organisms 6. organs

made of

function together

7. organ system Levels of Organization

INSTRUCTIONS: Use the words in the box below to fill in the blanks based on what you have learned about levels of organization. Words may be used more than once or not used at all.

Word Bank

atom cells elements macromolecules organelles organs tissues two

CLOZE 1

The smallest unit of matter that retains the properties of the matter is an

______. Molecules are made of ______or more atoms. Molecules can combine to form large molecules called ______. The biomolecules form small structures called ______that have specific functions in cells.

The different organelles combine to form ______which are found in living organisms. An organism is made of atoms, molecules, cells, tissues, and

______that all work together.

1 Levels of Organization

INSTRUCTIONS: Use the words in the box below to fill in the blanks based on what you have learned about levels of organization. Words may be used more than once or not used at all.

Word Bank

cell composition functions hierarchy molecules organ system organism organs tissues

CLOZE 2

The smallest unit in the hierarchy of organization within an organism is a

______. These structures are specialized and perform different

______. ______are made from similar cells that work together to perform a specific function. Tissues that work together to perform a specific function are called ______. Different organs that work together in the execution of a certain body function is an ______.

An ______is a body in which all the different organ systems work in unison to perform all functions of life.

2 BIO 1B.1 Complex Organic Molecules

A group of atoms that is held together by covalent bonds is known as a molecule. When bonding occurs between two or more carbon atoms, the group is known as an organic molecule. Biological Molecules

Biological molecules are composed of small repeating subunits that bond together to form larger units. The subunits, or building blocks, are called monomers. Polymers are the complex molecules formed from the repeating subunits. There are four basic classes of complex organic molecules, or macromolecules, that compose cells: carbohydrates, proteins, lipids, and nucleic acids. Each of the major classes of biological molecules is associated with different properties and functions within cells and whole organisms. Carbohydrates

Carbohydrates are organic macromolecules that are made up of carbon, hydrogen, and oxygen atoms. These atoms are combined in a ratio of:

1 carbon atom : 2 hydrogen atoms : 1 oxygen atom

The presence of multiple carbon-hydrogen bonds within carbohydrates makes them an excellent source of energy. The energy is released when these bonds are broken.

Carbohydrates may be simple or complex. The building blocks of carbohydrates are the simple sugars known as monosaccharides. Sugars such as glucose, fructose, and ribose are all examples of monosaccharides.

Glucose, a monosachharide, is an important source of energy.

Monosaccharides can be combined to form more complex carbohydrates known as polysaccharides. Glycogen, starch, and cellulose are all examples of polysaccharides. These compounds are typically used for long term energy storage or as structural molecules. Cellulose, for example, is a major component found in the cell walls of plants.

Dietary fiber is a special class of carbohydrate that cannot be digested by the human body. Cellulose is one example of a carbohydrate that acts as fiber. Dietary fiber is an important part of a healthy diet because it is essential for proper digestion. Humans can get fiber by eating many different kinds of plants, such as whole grains, legumes, prunes, and potatoes.

Lipids

Lipids are organic macromolecules that are insoluble in water. This is why lipids are often found in biological membranes and other waterproof coverings (e.g. plasma membrane, intracellular membranes of organelles). These lipids play a vital role in regulating which substances can or cannot enter the cell.

The most important lipids, however, are fats. Triglycerides are a type of fat that contain one glycerol molecule and three fatty acids.

Fatty acids are long chains of CH2 units joined together. The fatty acids in saturated fats do not contain any double bonds between the CH2 units whereas the fatty acids in unsaturated fats contain some carbon- carbon double bonds. Saturated fats are found in butter, cheese, chocolate, beef, and coconut oil. Unsaturated fats are found in olives and olive oil, peanuts and peanut oil, fish, and mayonnaise.

Fats are important because they are a major source of energy. Since they contain even more carbon- hydrogen bonds than carbohydrates, fatty tissue has the ability to store energy for extended periods of time Proteins

Proteins are organic macromolecules that are composed of amino acid monomers. There are 20 essential amino acids that are used by all living things to construct proteins. These amino acids are made up of the elements carbon, hydrogen, oxygen, and nitrogen. Some of the amino acids also contain sulfur. Three of the amino acids are shown below.

Proteins differ from each other due to the number and arrangement of their component amino acids. Proteins also take on unique shapes as determined by their amino acid sequences.

Water is the most abundant molecule in the body, but proteins are the second most abundant type of molecule. Proteins assist with muscular contractions and serve many structural roles. For example, cartilage and tendons are made of a protein known as collagen, and a protein known as keratin is found in hair, nails, feathers, hooves, and some animal shells. Proteins are also involved in cell signaling, cell transport, immune responses, and the cell cycle. Hormones are protein-containing substances that play a role in the regulation of cellular functions. Substances containing proteins that play a role in defense are antibodies. Other proteins known as enzymes are involved in many biological processes such as the breakdown of food molecules, transport across the cell membrane, and cellular signaling and regulation. Most enzymes have a surface with one or more deep folds. The folds make pockets called active sites. The active sites match folds in the substrate's surface, like a key matches a lock. So, the enzyme only catalyzes specific reactions. Once an enzyme binds to a substrate, the amount of energy needed to start a chemical reaction with the substrate is reduced. In some cases, the activation energy is too high to overcome without an enzyme. Nucleic Acids

Nucleic acids are formed from nucleotide monomers. Nucleotides are chemical compounds that are primarily comprised of the elements carbon, hydrogen, oxygen, nitrogen, and phosphorus. They consist of a five-carbon sugar, a nitrogenous base, and one or more phosphate groups. There are two main types of nucleic acids - ribonucleic acids (RNA) and deoxyribonucleic acids (DNA). These nucleic acids are different because their five-carbon sugars are different. RNA contains ribose, and DNA contains deoxyribose.

DNA and RNA also have different functions. DNA stores genetic information and encodes the sequences of all the cell's proteins. RNA is involved in the direct production of the proteins.

Nucleic acids are also different because the sequence of nitrogenous bases that they contain are different. There are five nitrogenous bases found in nucleic acids. Adenine (A), cytosine (C), and guanine (G) are found in both DNA and RNA. Thymine (T) is only found in DNA, and uracil (U) is only found in RNA. Summary of Macromolecules

The table below compares the basic properties, monomers, and functions of the four biological macromolecules.

Carbohydrates Lipids Proteins Nucleic Acids • nucleotides Building • amino acids • monosaccharides (glucose, • glycerol (adenine, Blocks (20 different fructose, ribose, etc.) • fatty acids cytosine, guanine, (monomers) amino acids) thymine, uracil) • muscle • energy contraction storage • oxygen • energy storage Function(s) • insulation transport • information • structural in cells • protective • immune storage support (plant cell walls) covering responses • lubrication • chemical reactions • carbon • carbon • carbon • carbon • hydrogen • hydrogen Elements • hydrogen • hydrogen • oxygen • oxygen Present • oxygen • oxygen • nitrogen • nitrogen • sulfur (some) • phosphorus Water • yes • no • many • yes Soluble • sugars • fats • enzymes • RNA Examples • starches (glycogen & • oils • hemoglobin • DNA cellulose) • waxes • muscle fibers

BIO1B.1 Macromolecules Question 1 .

Which of the following is a protein molecule that is found in red blood cells and transports oxygen throughout the body?

A. glycogen

B. cholesterol

C. insulin

D. hemoglobin

Question 2 .

A large carbohydrate molecule is composed of several subunits, such as glucose.

An example of a large carbohydrate molecule is ______.

A. starch

B. cellulose

C. glycogen

D. all of these

Question 3 .

______are nonpolar macromolecules found in cell membranes; they prevent ions from freely entering cells.

A. Proteins

B. Lipids

C. Carbohydrates

D. Nucleic acids

The process of translation is shown in the diagram below.

Which of the following structures is labeled as X in the diagram?

A. nucleic acid

B. DNA

C. amino acid

D. enzyme

Question 5 .

Protein molecules are composed of long chains of ______.

A. RNA

B. ribosomes

C. DNA

D. amino acids

Question 6 .

Sugars are a type of ______. They are produced by plants and release energy when they are broken down into smaller molecules.

A. protein

B. hydrocarbon

C. lipid

D. carbohydrate

Carbohydrates are composed of which three elements?

A. oxygen, hydrogen, and nitrogen

B. carbon, nitrogen, and phosphorus

C. oxygen, sulfur, and phosphorus

D. carbon, hydrogen, and oxygen

Question 8 .

Lipids are organic macromolecules that serve a variety of purposes. What is the most important role of lipids?

A. to metabolize sugar

B. to build muscles

C. to oxygenate blood

D. to store energy

Question 9 .

Directions: Select ALL the correct answers.

Which of the following is true about nucleic acids?

Nucleic acids always consist of a five-carbon sugar, a nitrogenous base, and one or more phosphate groups.

Nucleic acids are usually insoluble in water and are used for long term energy storage.

Both DNA, which stores genetic information and encodes protein sequences, and RNA, which is involved in the direct production of proteins, are nucleic acids.

Glucose, cellulose, and starch are examples of nucleic acids found in most cells.

The image below shows the structure of five nitrogenous bases.

Which of the following statements is true regarding all five of these nitrogenous bases?

A. They all can be found within a molecule of RNA.

B. They all can be found within all living organisms.

C. They all contain the same molecular structure.

D. They all can be found within a molecule of DNA.

Question 11 .

Nucleic acids are one of the four major macromolecules.

The main function of nucleic acids is to

A. act as enzymes, cell signals, and structural support for the cell.

B. aid in development, the immune system, and blood clotting.

C. absorb energy from the Sun and transport it around the cell.

D. carry genetic material that helps to create structures inside the cell.

Question 12 .

Cellular processes are carried out by many different types of molecules, mostly proteins. The function of each protein molecule depends on its shape which, in turn, is determined by the protein's specific sequence of ______.

A. amino acids

B. monosaccharides

C. nucleotides

D. triglycerides

In which of the following are lipids found?

A. some vitamins and steroids

B. saturated and unsaturated fats

C. biological membranes

D. all of these

Question 14 .

Which of the following would be most likely to cause a change in the sequence of amino acids of a protein product produced by a cell?

A. using an enzyme to catalyze the protein synthesis reaction

B. altering the amount of energy available to the cell

C. increasing the volume of the cell

D. changing the sequence of DNA nucleotides in the cell

Question 15 .

A student is given a small amount of unknown tan-colored liquid substance. This unknown liquid is placed into a glass of water and mixed. Despite mixing, the tan liquid remains separated from the water and collects as a large droplet at the top. Which of the macromolecule groups is this liquid most likely to be a member of?

A. lipids

B. proteins

C. carbohydrates

D. nucleic acids

1. D

2. D

3. B

4. C

5. D

6. D

7. D

8. D

9. --

10. B

11. D

12. A

13. D

14. D

15. A

Enzymes are biological catalysts that provide an alternate pathway for chemical reactions to occur. An enzyme-catalyzed reaction has a lower activation energy than the same reaction uncatalyzed, so an enzyme increases the overall rate of a chemical reaction. Enzymes & Activation Energy

Substances that increase the rate of a chemical reaction without being consumed in the reaction are called catalysts. Enzymes are biological catalysts, and they are generally composed of proteins. According to collision theory, chemical reactions occur when suitable reactants collide with sufficient energy. The amount of energy needed for a reaction to occur is called the activation energy of the reaction. The lower the activation energy of a reaction, the more likely it is that the reaction will occur. Enzymes provide an alternate pathway for chemical reactions to occur that has a lower activation energy than if no enzyme was involved.

The graph below compares the activation energy of a catalyzed reaction to the same reaction uncatalyzed.

Catalysts are substances that make it more likely that a chemical reaction will occur. Biological catalysts are called enzymes. Role of Enzymes in the Cell

The vast majority of enzymes are proteins that are produced inside the cell by ribosomes. Ribosomes produce specific enzymes to act on specific substances, called substrates. For example, hydrogen peroxide can be harmful to cells. The enzyme catalase catalyzes the breakdown of hydrogen peroxide into water and oxygen. In this case, hydrogen peroxide is the substrate of the catalase enzyme.

This enzyme binds to its substrate, then splits the substrate molecule into two products. After the reaction, the enzyme is free to catalyze the breakdown of another substrate molecule.

Image courtesy of Darryl Leja, NHGRI

While many enzymes are responsible for breaking down molecules, others are important in building them up. For example, DNA polymerase is the enzyme responsible for synthesizing new strands of DNA during the process of DNA replication.

A huge number of the chemical reactions that occur in cells are catalyzed by enzymes. The activation energy of many reactions is simply too high to overcome without enzymes; in fact, such reactions may not occur at all in the absence of an enzyme. The importance of enzymes to organisms cannot be understated. For example, without enzymes catalyzing metabolic reactions, cells would not be able to perform metabolism quickly enough to support life.

The concentration of an enzyme inside the cell determines how quickly a particular reaction proceeds. As long as sufficient substrate is available, increasing the concentration of an enzyme will increase the rate of a reaction. Cells can control chemical reactions by increasing or decreasing the intracellular concentration of an enzyme. Since enzymes are not consumed in a chemical reaction, their concentration will remain constant until the cell triggers the re-uptake of the enzymes. Enzyme Shape & Function

The shape of an enzyme determines how it works and which substrate can fit into it. Most enzymes have a surface with one or more deep folds. Inside the fold is a pocket called an active site. The active site on the enzyme matches the shape of a particular substrate. Thus, the substrate and enzyme fit together like two pieces of a puzzle.

An enzyme's shape is key to how the enzyme functions. If an enzyme's shape changes, it may not function as well or at all. Enzymes are only able to work properly in a certain temperature and pH range. A molecule that binds to an enzyme and decreases its effectiveness is called an enzyme inhibitor. Some enzyme inhibitors bind to the same part of the enzyme that would be used by the substrate. Some medications are enzyme inhibitors that impact enzymes used by bacteria or viruses. Enzymes & Temperature

If the temperature inside a cell is too low, reactants will not collide with enough energy for a reaction to occur, even if the correct enzyme is present. If the temperature is too high, the shape of the enzyme can change, and its active site may no longer fit a substrate. When this happens, the enzyme is said to be denatured, and it cannot catalyze the reaction. As a result, the overall rate of the reaction will slow dramatically as temperature increases. In the diagram below, an enzyme has changed shape because the temperature inside the cell is too high.

Optimal temperature ranges can vary from enzyme to enzyme. Depending on its function and location in an organism, an enzyme may have unique temperature requirements. Enzymes & pH

Like temperature, pH can affect the function of an enzyme. Certain enzymes require acidic environments in order to function, while others require alkaline environments. Still others operate best at a neutral pH. In humans, for example, an enzyme called pepsin can withstand the acidity of the stomach, while an enzyme called pancreatic amylase is found in the alkaline environment of the small intestine. Outside its optimal pH range, an enzyme or its substrate can change shape. In extreme cases, the enzyme can be permanently denatured

BIO 1B.2 Enzyme Questions Question 1 .

The diagram below shows an enzyme-substrate complex.

What is the best comparison to the enzyme-substrate complex?

A. dime and penny

B. lock and key

C. salt and pepper

D. shoe and sock

Question 2 .

Lactose is a sugar found in milk products. Lactase is an enzyme that breaks down lactose so it can be absorbed into the bloodstream and turned into energy. However, people with lactose intolerance do not produce enough lactase enzymes to break down lactose. Which of the following best explains why other enzymes within the body cannot break down lactose for individuals with lactose intolerance?

A. Other enzymes within the body are destroyed after catalyzing reactions.

B. Other enzymes would catalyze the lactose reaction too quickly.

C. Other enzymes would decrease the temperature within the cell.

D. Other enzymes cannot bind to lactose due to enzyme specificity.

Question 3 .

Suppose that enzyme X catalyzes a reaction that involves the breakdown of a substrate. The products of this reaction are amino acids.

What is the enzyme's substrate?

A. a lipid

B. a protein

C. a carbohydrate

D. a mineral

The above graph shows how temperature affects the rate of a reaction that uses the catalase enzyme. At what temperatures, approximately, is the enzyme denatured?

A. between 27°C and 37°C

B. between 60°C and 100°C

C. between 0°C and 27°C

D. between 37°C and 60°C

Question 5 .

In order for cells to function properly, the enzymes that they contain must also function properly. The graph below shows how pH affects the activity of the enzyme salivary amylase.

From the information given, what can be inferred about cells that have salivary amylase?

A. They function best at a high pH.

B. They function best at a low pH.

C. They function equally well regardless of the pH level.

D. They do not function well at a pH that is too high or too low.

Which of the following can affect the function of a cell?

A. high temperature

B. low temperature

C. high acidity

D. all of these

Question 7 .

Siamese cats are characterized by light and dark regions of fur.

The darker parts occur on the cooler parts of the cat's body because the enzyme that catalyzes the formation of the dark pigment is more active when cool. This example shows that enzymes are affected by .

A. temperature

B. concentration

C. pH

D. all of these

Question 8 .

Homeostasis is the ability of an organism to maintain a relatively stable internal environment.

How would an organism's homeostasis be affected if it was not able to produce enzymes?

A. Without enzymes, biochemical reactions would cease completely.

B. Without enzymes, chemical reactions would not occur quickly enough to sustain life.

C. Without enzymes, ribosomes would break down proteins, rather than build them.

D. Without enzymes, the temperature inside cells would increase rapidly.

A person takes a bite of a sandwich that has meat, cheese, and bread. Enzymes in the person's saliva start the digestion process by helping break the sandwich down into simpler molecules that can be absorbed into the bloodstream. Which of these best describes how salivary enzymes perform this role?

A. The same enzyme binds to each type of molecule in the sandwich to catalyze the digestion process.

B. The same enzyme binds to each type of molecule in the sandwich to decrease the overall activation energy.

C. Different enzymes break down different molecules in the sandwich based on the pH of each molecule.

D. Different enzymes break down different molecules in the sandwich based on their three-dimensional shape.

Question 10 .

In order to maintain life, organisms must produce, modify, transport, and exchange materials. What is this process called?

A. homeostasis

B. circulation

C. metabolism

D. digestion

Question 11 .

Proteins are used for many structural functions such as in the actin and myosin in muscle or as a part of the cytoskeleton scaffolding that maintains cell shape. What other main function do proteins serve?

A. as coding for genotypic expression and phenotypic traits

B. as waterproof membranes to regulate the transport of molecules in and out of the cell

C. as cellulose to form the major structural component of plant cell walls

D. as enzymes to control the rate of reactions and regulate cellular activity

Question 12 .

Which of the following describes the role that enzymes play in the process of metabolism?

A. Enzymes provide the chemical energy that is broken down and released during metabolism.

B. Enzymes increase the rate of the chemical reactions carried out during metabolism.

C. Enzymes carry the genetic instructions required for a cell to initiate metabolism.

Which of the following best describes an enzyme?

A. It slows the rate of a chemical reaction.

B. It can bind to any substrate.

C. It lowers the activation energy of a chemical reaction.

D. It functions properly at all temperatures.

Question 14 .

The diagram shows an enzyme and its substrate.

In the diagram, what does X represent?

A. the enzyme's glucose-fructose bond

B. the enzyme's catalyst

C. the enzyme's active site

D. the enzyme's globular protein

Question 15 .

Enzymes are catalysts. This means that they are able to speed up chemical reactions. Which of the following statements is also true of enzyme catalysts?

A. They must be continuously replaced after each catalyzed reaction.

B. They increase the energy that is released by reactions.

C. They increase the energy that must be absorbed by reactions.

D. They are not used up by reactions.

1. B

2. D

3. B

4. B

5. D

6. D

7. A

8. B

9. D

10. C

11. D

12. B

13. C

14. C

15. D

INSTRUCTIONS: Use the words in the box below to fill in the blanks based on what you have learned about biomolecules. Words may be used more than once or not used at all.

Word Bank

amino acids ATP biomolecules elements fatty acids function monomers nucleotides phosphate polymers saccharides structural

CLOZE 1 ______are bonded together to form monomers which are bonded together to form ______. Macromolecules are polymers; these are large molecules that are made of ______. Another name for the macromolecules that are essential for the survival of organisms is ______.

Examples of monomers include the ______in carbohydrates,

______in lipids, ______in proteins, and

______in nucleic acids. The monomers combine with each other or other groups of molecules to form the polymers that are necessary for organisms to

______properly and survive. Examples of required polymers include the energy molecule ______, hormones, and vitamins.

1 Biomolecules

INSTRUCTIONS: Use the words in the box below to fill in the blanks based on what you have learned about biomolecules. Words may be used more than once or not used at all.

Word Bank

carbohydrates cell membrane energy lipids one polymers proteins saccharides structural two

CLOZE 2 There are two major macromolecules that are found in organisms that are responsible for storing ______. ______are made of monomers of simple sugars; they have the chemical compound ratio of ______carbon atom to

______hydrogen atoms to ______oxygen atom. In addition to storing energy, carbohydrates provide ______support. ______are made of hydrocarbon chains of fatty acids; their functions include energy storage and components of the ______.

2 Biomolecules

INSTRUCTIONS: Use the words in the box below to fill in the blanks based on what you have learned about biomolecules. Words may be used more than once or not used at all.

Word Bank

cell membrane circulatory hormones immune proteins speed structural transporting sixty-four twenty

CLOZE 3 Amino acids are the building blocks of ______. There are a total of

______amino acids. Proteins have a variety of functions. They act as enzymes or catalysts to ______up the rate of reactions. Many

______such as insulin and neurotransmitters are made of proteins. Proteins are a significant part of the ______system because they provide antibodies to fight the foreign invaders. Proteins are also used for

______molecules. For example, hemoglobin is used to carry oxygen throughout the body, and proteins provide channels though the ______which allows larger molecules or ions to move in and out of the cell. Another function of proteins is to provide ______support, for example toenails and fingernails are made of the protein keratin.

3 Biomolecules

INSTRUCTIONS: Use the words in the box below to fill in the blanks based on what you have learned about biomolecules. Words may be used more than once or not used at all.

Word Bank

amino acid DNA energy functions nucleic acids nucleotides ribosomes ribose RNA structure

CLOZE 4 DNA and RNA are examples of ______. The

______molecule is the template for RNA. The ______molecules that are produced from the DNA are used by the cell’s

______to create polypeptide chains. Polypeptide chains are links of ______that form a protein. The macromolecules work together to carry out the ______of living organisms.

4 Biomolecules

INSTRUCTIONS: Use the words in the box below to fill in the blanks based on what you have learned about biomolecules. Words may be used more than once or not used at all.

Word Bank

conclusions hypotheses investigations Iron-Sulfur Oparin-Haldane organic polymer RNA world

CLOZE 5 There are many ______as to the origin of monomers. The

______hypothesis suggests that the monomers arose from a reducing atmosphere of methane, ammonia, and water. The ______hypothesis suggests that the monomers came from iron sulfide compounds. From monomers, scientists hypothesize that life was able to develop. One hypothesis, called ______hypothesis, suggests that RNA was created by nucleotides prior to DNA, and RNA supported pre-cellular life. Scientists are proposing many different hypotheses, but no tests have conclusively proven any of the hypotheses at this time.

5 Enzymes

INSTRUCTIONS: Use the words in the box below to fill in the blanks based on what you have learned about enzymes. Words may be used more than once or not used at all.

Word Bank

body catalyst enzymes increasing lowering protein recycled slow speed used up

CLOZE 1 ______are proteins that ______up the rate of a reaction. Enzymes are a type of ______. The difference between a catalyst and an enzyme is that the enzyme is a ______and is organic; catalysts do not have to be organic nor do they have to be proteins. An enzyme works by

______the activation energy of a reaction. Once the reaction occurs, the enzyme is ______so that it can be used again in other reactions.

1 Enzymes

INSTRUCTIONS: Use the words in the box below to fill in the blanks based on what you have learned about enzymes. Words may be used more than once or not used at all.

Word Bank

active site converts enzyme-substrate function induced fit pocket products reactions specific unusable

CLOZE 2 Enzymes are ______to the reaction. Each enzyme has a different shape based on its ______. The enzyme contains a groove called an

______in which the substrate fits. The fit is often referred to as a lock-and-key fit since the active site will only allow certain substrate(s) to enter. Once the substrate enters the active site, the hydrogen bonds between the substrate and enzyme cause an ______. The substrate and enzyme are bonded together in a

______complex. Once the ______are formed and released, the enzyme is available to repeat the reaction with additional substrates.

2 Enzymes

INSTRUCTIONS: Use the words in the box below to fill in the blanks based on what you have learned about enzymes. Words may be used more than once or not used at all.

Word Bank

anabolic bonds catabolic energy metabolic pathway metabolism product reactants reactions substrates

CLOZE 3 Most processes that occur within the body require a number of enzymes to produce the needed

______. The series of reactions that begins with the initial substrate, creates a series of intermediates, and ends with the product, is known as a

______. A ______pathway causes macromolecules to break down and release energy that can be used to produce ATP.

An ______pathway builds up macromolecules and requires energy from ATP. ______is the balance between catabolic and anabolic pathways in the body.

3 Enzymes

INSTRUCTIONS: Use the words in the box below to fill in the blanks based on what you have learned about enzymes. Words may be used more than once or not used at all.

Word Bank

activate both coupled denatured energy occur optimal protein shape temperature

CLOZE 4 Some enzymes have more than one active site and each site will attract a different substrate because the active site has a different ______. These enzymes are able to have ______reactions or two reactions occurring at the same time.

Energetically unfavorable reactions require a more energetically favorable reaction to occur at the same time so that the less favorable reaction can ______. For coupled reactions to occur, ______must happen at the same time, or neither reaction can occur. Enzymes must operate under ______conditions. If the

______or pH is too high or too low, the enzyme will not work as well. If the environment around an enzyme reaches temperatures or pH too extreme for the enzyme, the enzyme will become ______.

4 1C.1 Functions and Interactions of Organelles

All living organisms on Earth are made up of microscopic structures called cells. There are many types of cells. Some organisms are unicellular, while other organisms, including humans, are multicellular. Cells generally share a similar structure. Cell Structure

Most cells contain smaller structures, called organelles. Organelles are groups of complex molecules that function like "organs" of a cell. Like the organs of the body, organelles of a cell perform different functions. Some of the organelles found in cells are shown in the diagram of the animal cell below.

Although some cells contain a different assortment of organelles than others, a list of the organelles commonly found in eukaryotic cells appears below: • Centrosome — an organelle near the cell nucleus that helps organize the microtubules in the cell's cytoplasm. The centrosome is made up of a two cylindrical organelles called centrioles surrounded by proteins. During cell division, the centrosome organizes the cytoskeletal structure called the mitotic spindle that is needed for the cell to divide. • Cytoplasm — the clear, gelatinous material found inside cells that supports and holds cellular organelles. It is the site of many cellular processes. The cytoplasm contains a cytoskeleton which helps to maintain the cells shape and structure. • Cytoskeleton — a cellular scaffolding that is made up of microfilaments and microtubules. The cytoskeleton of a cell helps the cell maintain its shape, protects the cell, enables the cell to move, and plays important roles in both intracellular transport and cellular division. • Cell membrane — a selectively permeable lipid bilayer that acts as a boundary layer around the cytoplasm, thus separating cells from their outside environments. In addition to being able to recognize chemical signals, the cell membrane is selectively permeable to chemicals and controls which molecules enter and leave the cell. Nutrients first enter the cell through the cell membrane. • Cell wall — a secretion of the cell membrane that is found in plants, fungi, bacteria, and many protists. It provides protection from physical injury and provides structural support. • Choroplast — the food producer in a plant cell. During a process known as photosynthesis, chloroplasts absorb light energy from the Sun and produce food in the form of glucose sugar from carbon dioxide and water. • Chromatin — a collection of DNA and proteins that contains the hereditary information of an organism. The chromatin is loosely packed during interphase to allow for easy access for gene expression. Prior to cell division, the chromatin condenses to form chromosomes. • Endoplasmic reticulum (ER) — transports proteins within cells. The endoplasmic reticulum is also the location of lipid synthesis on the smooth side, and proteins are synthesized on the ribosome- studded, rough ER. • Golgi apparatus — processes and transports wastes (and other materials) out of the cell by a process called exocytosis. In addition to playing an important role in waste disposal, the Golgi apparatus also processes, sorts, and modifies proteins in cells. • Lysosome — a membrane-bound organelle found in animal cells that contains enzymes specialized to break down ingested materials, secretions, and wastes. These wastes (and other materials) may then be processed and transported out of the cell by the Golgi apparatus. • Microfilaments — a major component of a cell's cytoskeleton. They function in determining cellular shape, as well as aiding in cellular movement. They are important for the formation of many different cellular projections that can allow a cell to move through its environment. • Microtubules — components of cilia and flagella as well as the cytoskeleton of a cell. Microtubules are hollow rods that help give a cell its shape and can also aid the cell in locomotion and the transport of materials through the cell. • Mitochondria — take in nutrients, break them down and create energy (or ATP) for the cell. The inner membrane of a mitochondrion is folded into cristae. The cristae increase the surface area of the inner membrane and enhance the mitochondrion's ability to produce ATP through the process of cellular respiration • Nuclear membrane — double lipid bilayer that encloses the genetic material of a cell. It separates the nucleus of a cell from the cytoplasm. There are nuclear pores within the nuclear membrane that allow for the exchange of materials between the nucleus and the cytoplasm. The nuclear membrane is sometimes called the nuclear envelope. • Nucleus — the "brain" of the cell. It contains the nucleolus and the cell's DNA. • Nucleolus — found within the nucleus of a cell and is responsible for synthesizing ribosomes and ribosomal RNA. • Ribosome — RNA and protein complex that is found in all cells. During translation, ribosomes join amino acids together to form proteins. • Vacuole — stores water and ingested food in a fluid sack. In plant cells, the central vacuole produces turgor pressure against the cell wall for cellular support. Plant Cells

Plant cells contain some structures that are different from animal cells.

Plant cells have chloroplasts, a cell wall, and a large central vacuole that are not found in animal cells.

Organelles present in plant cells include: • The chloroplasts are the food producers in a plant cell. During a process known as photosynthesis, chloroplasts absorb light energy from the Sun and produce food in the form of glucose sugar from carbon dioxide and water. • A large, central vacuole stores water and ingested food in a fluid sack and helps remove waste from the cell. The central vacuole in plants produces turgor pressure against the cell wall for cellular support. (Vacuoles may be present in certain animal cells. However, the vacuoles found in animal cells only serve minor functions. They are also very small in comparison and tend to be more numerous when present.) • The cell wall is a secretion of the cell membrane; it provides protection from physical injury and, with the vacuole, it provides structural support. Since it is made primarily of cellulose, it gives plant cells a structure that is more rigid than that of animal cells.

The video below discusses the structure of a plant cell and the functions of organelles found within plant cells. To watch the video, click on the play button on the gray bar below. Clip provided by Education Clip Library with permission from ITN Source

Cells within multicellular organisms are highly specialized for the specific functions they perform. So, the type and number of organelles present can vary greatly. For example, certain plant cells do not contain chloroplasts. Cells located in the roots are not exposed to sunlight and do not photosynthesize. Therefore, chloroplasts are not necessary. The same is true for cells that compose animals and all other complex organisms. Animal Cells

Animal cells contain some structures that are different from plant cells.

Animal cells possess lysosomes and centrioles, which plant cells do not.

Organelles present in animal cells include: • Lysosomes contain enzymes which digest food particles, excess or old organelles, and engulfed foreign particles, such as viruses or bacteria. • The centrioles play a major role organizing the mitotic spindle during cell division. All cells are surrounded by some type of membrane. Plant cells have a cell membrane and a cell wall, while animal cells only have a cell membrane. It is the lack of a cell wall in animal cells that allowed animals to develop greater diversity of cell types, tissues, and organs. Organelles Interact to Fulfill Functions

In all types of cells, organelles must interact with one another to fulfill the functions needed to sustain life. Growth

Cells of multicellular organisms grow as the organism grows. As cells grow, they require new proteins and lipids. Proteins are synthesized by ribosomes using instructions from DNA in the nucleus. After proteins are synthesized, they are modified in the rough endoplasmic reticulum and packaged in the Golgi apparatus, which directs them to their destination. Lipids that will be inserted into the cell membrane are synthesized by smooth endoplasmic reticulum. Division

In multicellular organisms, cells divide so an organism may grow or repair damaged tissue. Cell division requires the interaction of the centrosome and cytoskeleton, which work together to ensure that copies of the cell's DNA are correctly divided among two daughter cells. Nutrient Acquisition

Cells must acquire nutrients in order to perform life processes. Cells take in nutrients with the help of specialized proteins embedded in their membranes. These proteins are produced and inserted into the membrane through a process that involves the ribosomes, endoplasmic reticulum, and the Golgi apparatus. Once within the cell, nutrients are often transported along the cytoskeleton in vesicles formed by the cell membrane. Extraction of Energy

Cells use the nutrients that they acquire to extract energy. Nutrients that enter the cell across the cell membrane may be partially broken down by proteins in the cytoplasm. Components of these nutrients are sent on to the mitochondria, where they are further broken down to make ATP. ATP from the mitochondria is sent to all organelles in the cell to provide them with energy. Waste Disposal

After a cell has acquired and used nutrients for cellular processes, the cell must be able to dispose of waste materials. Some wastes can be directly transported across the cell membrane. In animal cells, waste products are typically broken down by lysosomes. Lysosomes contain enzymes specialized to degrade waste material. These enzymes are originally produced by ribosomes and the rough endoplasmic reticulum. They are then packaged and released in membrane-bound vesicles by the Golgi apparatus. These vesicles mature into lysosomes, which move throughout the cell and pick up waste products or other cellular debris. After a lysosome has broken down the waste material, it fuses with the cell membrane to release its contents outside of the cell.

The nucleus, ribosomes, endoplasmic reticulum, and Golgi apparatus interact to synthesize proteins and lysosomes. Structure Affects Function

The structure of organelles enables them to perform their functions. Several examples are discussed below. • The folded cristae of a mitochondrion greatly increase the surface area of the inner membrane where cellular respiration takes place. As a result, each mitochondrion can produce more ATP than if cristae were absent. • The cell membrane is composed of a double layer of lipid and protein molecules. This specific arrangement turns the cell membrane into a gate that allows precise control over which substances enter or leave the cell. • In plants, the cell wall is a rigid outer layer made primarily of carbohydrates. Unlike the pliable cell membrane, the cell wall is strong enough to prevent plant cells from collapsing when they lose water.

Surface area plays an important role in the functions of the cell. Many of the reactions that sustain life take place on surfaces inside the cell. Structures that result in a larger surface area increase the number of reactions that can take place on them.

BIO 1C1 Question 1 .

Which of the following statements correctly describes how two cellular structures interact to produce energy for a cell?

A. Mitochondria synthesize enzymes and deliver them to the chloroplast to produce cellular energy.

B. Chloroplasts synthesize and release enzymes that are absorbed by the nucleus to produce cellular energy.

C. Ribosomes synthesize proteins that are used as enzymes in the mitochondria to produce cellular energy.

D. Vacuoles synthesize proteins that are broken down by the ribosomes to produce cellular energy.

Question 2 .

In the above diagram of an animal cell, what is the function of structure 3?

A. gives the cell structural support, encloses the cytoplasm, and helps regulate what enters and exits the cell

B. serves as the control center of the cell and stores the cell's genetic information

C. contains the cell's organelles and is the site where many cellular processes are performed

D. contains digestive enzymes that help rid the cell of old organelles, food particles, and other wastes

Question 3 .

The brain regulates all functions and processes of an animal. At the cellular level, the ______regulates all cell activity.

A. nucleus

B. mitochondrion

C. centriole

A diagram of an animal cell is shown below.

What is the function of organelle 2?

A. to aid in protein synthesis by joining amino acids together to form polypeptides

B. to store ions, create and store steroids, and synthesize and package proteins

C. to collect, package, and distribute molecules produced by the cell

D. to supply the cell with energy, in the form of ATP, through the process of cellular respiration

Question 5 .

Which statement best describes how vacuoles and lysosomes interact in an animal cell?

A. Lysosomes contain enzymes that digest the contents of vacuoles.

B. Lysosomes produce glucose, which is converted to energy by vacuoles.

C. Vacuoles transport proteins to be packaged and modified by lysosomes.

D. Vacuoles direct lysosomes to synthesize proteins.

The image below shows an animal cell.

What is the organelle labeled 3 in the image, and how does it interact with other parts of the cell to perform a function?

A. It is a lysosome, and it interacts with the part labeled 5 to secrete waste materials from the cell.

B. It is a centrosome, and it interacts with the part labeled 4 to form a structure that helps the cell divide.

C. It is a centrosome, and it interacts with the part labeled 2 to help the cell make energy.

D. It is a lysosome, and it interacts with part labeled 1 to form a structure that breaks down waste products.

Question 7 .

The Golgi complex in a cell interacts with

A. mitochondria by sending them nutrients for the production of ATP.

B. the endoplasmic reticulum by producing ribosomes for the rough side of the structure.

C. the cell membrane by packaging wastes for release outside the cell.

D. the nucleus by receiving genetic instructions for the construction of proteins.

Question 8 .

Eukaryotic cells contain organelles that harvest energy from organic compounds to make ATP. ATP is the main form of energy used by cells. Which cell organelles are responsible for making most of the cell's ATP?

A. chloroplasts

B. endoplasmic reticulum

C. mitochondria

D. lysosomes

Directions: Drag the tiles to the correct boxes to complete the pairs.

Match each cell structure with the city structure to which it is most similar in function.

mitochondrion endoplasmic Golgi nucleus cell reticulum apparatus membrane

city hall

security gate

factory

post office

power plant

Question 10 .

The mitochondria of eukaryotic cells release energy from glucose molecules through the process of cellular respiration. Before cellular respiration can occur, however, glucose from another part of the cell must be transported to the mitochondria.

Where in a plant cell is glucose produced?

A. in the nucleus

B. in the ribosomes

C. in the vacuoles

D. in the chloroplasts

Question 11 .

Which of the following describes a function of a vacuole?

I. storage of water II. storage of cellular waste III. protein synthesis IV. structural support

A. II and III only

B. I, II, III, and IV

C. IV only

D. I, II, and IV only

Microfilaments are a component of a cell's cytoskeleton and are made of the protein actin. They are important for giving a cell its shape and also aid in ______.

A. protein synthesis

B. DNA replication

C. cellular movement

D. energy conversion

Question 13 .

Directions: Select each correct answer. More than one answer may be correct.

The skeletal system provides structure and support for animals. Which of the following provides structure and support for a plant cell?

mitochondrion chloroplast nucleus cell membrane endoplasmic reticulum central vacuole cell wall Golgi apparatus

Question 14 .

The circulatory system distributes oxygen and nutrients to the many cells in an animal's body. At the cellular level, the organelle that is responsible for transporting important substances through the cell is the

A. lysosome.

B. endoplasmic reticulum.

C. nucleus.

D. cell wall.

Question 15 .

The plasma membrane of a cell regulates substances that enter and exit the cell. The plasma membrane also transmits cellular signals and protects the cell from its external environment. Which of the following best describes how the structure of the plasma membrane relates to its function?

A. It is made of charged particles that transition between cells to transport materials and signals.

B. It is made of a phospholipid bilayer that is embedded with proteins to make it selectively permeable.

C. It is made of a single layer of flexible, permeable lipids to allow nutrients to enter easily.

D. It is made of rigid, interlocking proteins to provide protection and structure.

The stomach is the organ in animals that contains a mixture of digestive enzymes and is responsible for breaking down food. What organelle carries out the same function at the cellular level?

A. endoplasmic reticulum

B. mitochondrion

C. lysosome

D. vacuole

1. C

2. B

3. A

4. D

5. A

6. B

7. C

8. C

9. --

10. D

11. D

12. C

13. --

14. B

15. B

16. C

The cell is the fundamental unit of structure and function in all living organisms. Cells can be classified into two major types: prokaryotes and eukaryotes. Prokaryotes Prokaryotic cells do not have a true nucleus or other membrane-bound organelles. The word prokaryote comes from the combination of the Greek (pro-) "before" and (karyon) "kernal" or "nucleus."

This is a diagram of a typical bacterial cell. Notice that the DNA is not enclosed within a nucleus.

Image courtesy of Wikipedia. Prokaryotic organisms differ from eukaryotic organisms in complexity and structure.

• Except for a few species, most prokaryotic organisms are unicellular, or single-celled. • All prokaryotes lack a well-defined nucleus and are much smaller and simpler than eukaryotic organisms. • Although prokaryotes do have genetic material (DNA), their DNA is not separated from the rest of the cell by a nuclear membrane. Also, prokaryotic DNA is not arranged in chromosomes, and it tends to be circular rather than linear. • Prokaryotic cells do not contain mitochondria, but they can get energy from sunlight or chemicals in their environments. • Prokaryotes have simpler stages of growth and development. • Simple organisms, such as bacteria, blue-green algae, and archaea, are examples of prokaryotes.

Eukaryotes Eukaryotic cells have nuclei and organelles that are surrounded by membranes. The word eukaryote from the combination of the Greek (eu-) "true" and (karyon) "kernal" or "nucleus." Eukaryotic organisms are more complex than prokaryotes.

• Most eukaryotic organisms are multicellular, or multi-celled. • The genetic material (DNA) in eukaryotic cells is organized into chromosomes and separated from the cytoplasm by the nuclear membrane. • Cells in multicellular eukaryotes can be organized into tissues, organs, and organ systems. • Developmental stages of single-celled eukaryotes are more complex than prokaryotic stages, and developmental stages of multi-celled eukaryotes are even more complex. • Protozoa, fungi, plants, and animals are all examples of eukaryotes. Comparison of Prokaryotes and Eukaryotes There are many differences between eukaryotes and prokaryotes.

The top portion of this diagram points out the differences between a bacterium (prokaryote) and a typical animal cell (eukaryote). Prokaryotic cells are far simpler and smaller than eukaryotic cells. Eukaryotic cells can be anywhere between 5—500x as large as prokaryotic cells Adapted from images courtesy of NIH and Wikipedia.

The following table provides a more detailed comparison of prokaryotic and eukaryotic cells. Characteristic Prokaryote Eukaryote Cells are enclosed within a plasma

membrane.

Cells contain DNA.

Cells contain ribosomes.

Cell membranes are surrounded by a cell plants, most fungi, and some

wall. protists

Cells contain a nucleus.

Includes unicellular organisms.

Includes multicellular organisms.

All cells are able to perform all functions

necessary for life.

Plant, Animal, & Fungal Cells

All living organisms on Earth are made up of microscopic structures called cells. There are many types of cells. Three types of eukaryotic cells are plant cells, animal cells, and fungal cells. Cell Structures Cells consist of many smaller structures that each perform different functions. In eukaryotic cells, some of these structures, like the nucleus and mitochondrion, are enclosed in their own membranes. Because they perform functions for cells much like organs perform functions for the body, these membrane-bound structures are called organelles. Which organelles are present in a cell depends on the type and function of the cell.

Plant, animal, and fungal cells share many of the same structures. The structures that can be found in all three types of cells are discussed in the list below. • The nucleus is the control center of the cell. It contains chromosomal information composed of long, thin strands of DNA that control cell metabolism and heredity. • Ribosomes are RNA and protein complexes that are found in all cells. These complexes receive instructions from the nucleus to construct proteins by joining amino acids together to form polypeptides. • The cytoplasm is the suspension fluid that contains all of the organelles of the cell located between the nucleus and the cell membrane. Materials move from place to place within the cytoplasm through a process known as cytoplasmic streaming. Because of its high water content, the cytoplasm is also the site of most of the chemical reactions that take place in the cell. • The cytoskeleton extends throughout the cytoplasm of the cell. The cytoskeleton, which is made up of protein microfilaments, acts like a cellular scaffolding that helps the cell maintain its shape. Some cells can move through the use cilia or flagella, which are cytoskeleton filaments that extend from the cell's membrane. Because the microfilaments of the cytoskeleton can extend and contract, they also play a role in intracellular transport and cell division. • The cell membrane (or plasma membrane) acts as a boundary layer around the cytoplasm that separates a cell from its outside environment. Cell membranes are constructed of proteins and a phospholipid bilayer. Some proteins function as receptors that send and receive chemical messages. In addition to being able to recognize chemical signals, the cell membrane is selectively permeable to chemicals and controls which molecules enter and leave the cell. • The endoplasmic reticulum (or ER) is responsible for storing ions, creating and storing steroids, and synthesizing and packaging proteins. Lipids are synthesized on the smooth ER, and proteins are made on the ribosome-studded rough ER. These materials are used both inside and outside of the cell. The endoplasmic reticulum also transports proteins within cells. • The Golgi apparatus (or Golgi complex) processes and transports wastes and other materials out of the cell by a process called exocytosis. In addition to playing an important role in waste disposal, the Golgi apparatus also processes, sorts, and modifies proteins in cells. • Mitochondria take in nutrients, break them down, and transform them into a source of energy (ATP) for the cell. The inner membrane of a mitochondrion is folded into structures called cristae. • Plant Cells

Some structures are typically found only in plant cells. These structures are described below. • Chloroplasts are the food producers in a plant cell. During a process known as photosynthesis, chloroplasts absorb light energy from the Sun and produce food in the form of glucose sugar from carbon dioxide and water. • A large central vacuole stores water and ingested food in a fluid sack and helps remove waste from the cell. The central vacuole in plants produces turgor pressure against the cell wall for cellular support. (Vacuoles may be present in certain animal cells. However, the vacuoles found in animal cells only serve minor functions. They are also very small in comparison and tend to be more numerous when present.) • A cell wall made of cellulose is a secretion of the cell membrane; it provides protection from physical injury and, with the vacuole, it provides structural support. The cell wall gives plant cells a structure that is more rigid than that of animal cells. The video below discusses the structure of a plant cell and the functions of organelles found within plant cells. To watch the video, click on the play button below. Clip provided by Education Clip Library with permission from ITN Source Cells within multicellular organisms are highly specialized for the specific functions they perform. So, the type and number of organelles present can vary greatly. For example, certain plant cells do not contain chloroplasts. Cells located in the roots are not exposed to sunlight and do not perform photosynthesis. Therefore, chloroplasts are not necessary.

Animal Cells

Some structures are typically found only in animal cells. These structures are described below. • Lysosomes contain enzymes which digest food particles, excess or old organelles, and engulfed foreign particles, such as viruses or bacteria. • Centrosomes play a major role in organizing the cytoskeleton into a mitotic spindle during cell division. All cells are surrounded by some type of membrane. Plant cells have a cell membrane and a cell wall, while animal cells only have a cell membrane. It is the lack of a cell wall in animal cells that allowed animals to develop greater diversity of cell types, tissues, and organs. Fungal Cells

Some structures are typically found only in fungal cells. These structures are described below. • Multiple nuclei can be seen in most types of fungal cells. In some cases, these nuclei are divided into compartments by perforated membranes called septa. In other cases, many nuclei are found in a single, long fungal cell. • A cell wall made of chitin performs a role similar to the cellulose-containing cell wall in plants. It provides structure and support to the fungal cell. Although fungi may resemble plants in some ways, fungal cells do not contain chloroplasts or chlorophyll, so they cannot make their own food and instead must acquire it from other sources. They accomplish this by releasing enzymes from special secretory bodies. These enzymes digest food in the surrounding environment so it can be absorbed directly into the fungal cell.

BIO 1C2 Eukaryotic and Prokaryotic Cells Question 1 .

Michelle has been given a microscope slide that contains a eukaryotic cell and a prokaryotic cell. What should she look for to distinguish the eukaryotic cell from the prokaryotic cell?

A. cytoplasm

B. ribosomes

C. nucleus

D. cell membrane

Question 2 .

Dr. Roberts examined the cells of four different organisms for the presence of various cellular structures. His observations are recorded in the table below. (An "X" indicates that the structure is present in the cell.)

cell cell wall chloroplasts mitochondria nucleus ribosomes vacuoles membrane 1 X X X X X X X 2 X X X X X 3 X X X 4 X X X X

Using the information in the table, which of the cells most likely came from a plant?

A. 1 and 3 only

B. 2 and 4 only

C. 3 only

D. 1 only

Question 3 .

Janice is analyzing the results of an investigation she performed to determine the origin of four different cells. Each cell was taken from an animal, a plant, or a fungus. The table below shows the data that Janice collected during her investigation.

Cell 1 Cell 2 Cell 3 Cell 4 Chloroplasts present absent absent absent Ribosomes present present present present Cell Wall present absent present present Multiple Nuclei absent absent present absent Cell Membrane present present present present Based on the information in the table, which cell must have been taken from a fungus?

A. Cell 4

B. Cell 2

C. Cell 1

D. Cell 3

A student in science class is using a light microscope to determine if a cell is prokaryotic or eukaryotic. Identification of which of the following cell parts would allow the student to definitively conclude that the cell is eukaryotic?

A. ribosome

B. nucleus

C. DNA

D. plasma membrane

Question 5 .

Which of the following cell structures can be found in prokaryotic cells?

A. chloroplasts

B. ribosomes

C. mitochondria

D. nuclei

Question 6 .

The image below shows three different types of cells.

Which correctly identifies each cell?

A. Cell A is a fungal cell, cell B is an animal cell, and cell C is a plant cell.

B. Cell A is a plant cell, cell B is an animal cell, and cell C is a fungal cell.

C. Cell A is a plant cell, cell B is an fungal cell, and cell C is a animal cell.

D. Cell A is a animal cell, cell B is an fungal cell, and cell C is a plant cell.

Plant cells and animal cells possess many of the same organelles. Which of the following organelles, however, would be indicative of a plant cell rather than an animal cell?

A. chloroplast

B. ribosome

C. mitochondrion

D. nucleus

Question 8 .

Which of the following statements correctly supports the conclusion that eukaryotic cells are more complex than prokaryotic cells?

A. Only eukaryotic cells contain membrane-bound organelles.

B. Only eukaryotic cells can be seen using a microscope.

C. Only eukaryotic cells contain DNA and RNA.

D. Only eukaryotic cells contain ribosomes.

Question 9 .

What feature do all eukaryotic and prokaryotic cells share?

A. a cell wall

B. membrane-bound organelles

C. DNA

D. a nucleus

Question 10 .

Directions: Select ALL the correct answers.

Which of the following can be found in both prokaryotic cells and eukaryotic cells?

ribosomes

nucleus

mitochondria

DNA

RNA

vacuoles

Which of the following is true about cells?

A. In general, eukaryotic cells do not have a true nucleus or membrane-bound organelles, whereas prokaryotic cells contain both a nucleus and organelles enclosed by membranes.

B. Neither prokaryotic cells nor eukaryotic cells ever contain both a true nucleus that is well-defined and organelles that are separated from the cytoplasm by membranes.

C. Both eukaryotic cells and prokaryotic cells always contain both a true nucleus that is well-defined and organelles that are separated from the cytoplasm by membranes.

D. In general, prokaryotic cells do not have a true nucleus or membrane-bound organelles, whereas eukaryotic cells contain both a nucleus and organelles enclosed by membranes.

Question 12 .

Which of the following best describes a difference between prokaryotic and eukaryotic cells?

A. Prokaryotic cells contain RNA that codes for genetic information, but eukaryotic cells contain DNA only.

B. Eukaryotic cells are more complex than prokaryotic cells because eukaryotic cells contain membrane-bound organelles.

C. Eukaryotic cells contain ribosomes that help synthesize proteins, but prokaryotic cells do not need these structures.

D. Prokaryotic cells are larger than eukaryotic cells because they must perform all life processes in a single cell.

1. C

2. D

3. D

4. B

5. B

6. B

7. A

8. A

9. C

10. --

11. D

12. B

Cells

Contains Golgi body Lacks membrane-bound organelles

Contains mitochondria Contains cytoplasm

Contains ribosomes Contains lysosomes

Contains chloroplasts Contains nucleus

Contains cell membrane Hereditary information is stored in DNA

Only unicellular Unicellular or multicellular

Divide by binary fission Divides by mitosis

Contains a plasmid Bacteria is an example

1 Prokaryotic and Eukaryotic Cells

Cells Contains Golgi body Contains mitochondria Contains chloroplasts Contains lysosomes Contains nucleus Unicellular or multicellular Divides by mitosis Eukaryotic Cell Both Hereditary information is stored in DNA Contains cytoplasm Contains cell membrane Contains ribosomes Prokaryotic Cell Only unicellular Divide by binary fission Contains a plasmid Lacks membrane-bound organelles Bacteria is an example

1 Prokaryotic and Eukaryotic Cells

Cells, continued

Answer the questions below.

1. Which type of cells lack a nucleus? Prokaryotic

2. Which type of cells contain ribosomes? Prokaryotic and eukaryotic

3. Which type of cells contain membrane-bound organelles? Eukaryotic

4. Why is a microscope needed to see a prokaryotic cell? Prokaryotic cells are unicellular and are so small that the individual organism cannot be seen by the naked eye.

5. What is wrong with this statement: “All multicellular organisms are eukaryotic and all single-celled organisms are prokaryotic.” The incorrect portion of the sentence is “all single-celled organisms are prokaryotic.” Prokaryotic cells are single-celled organisms, but not all single-celled organisms are prokaryotic. Some single-celled organisms, such as yeast, amoeba, or paramecium, are eukaryotic. Prokaryotic and Eukaryotic Cells

Cells, continued Using all of the following terms in the word bank, complete the graphic organizer.

Word Bank

cell DNA energy eukaryotic heredity lysosomes nucleus prokaryotic ribosomes

No 1. cell membrane-bound organelles Membrane-bound organelles

has Types are has

2. prokaryotic 3. eukaryotic both have contains

has

contains DNA 4. ribosomes has make 5. DNA

proteins mitochondria found in

6. nucleus

in found found

7. lysosome nuclear region produces controls

for 8. energy 9. heredity

digesting material Prokaryotic and Eukaryotic Cells

Cells Eukaryotic Cell Both Prokaryotic Cell

1 Prokaryotic and Eukaryotic Cells

Cells, continued

Answer the questions below.

1. Which type of cells lack a nucleus?

2. Which type of cells contain ribosomes?

3. Which type of cells contain membrane-bound organelles?

4. Why is a microscope needed to see a prokaryotic cell?

5. What is wrong with this statement: “All multicellular organisms are eukaryotic and all single-celled organisms are prokaryotic.”

2 Prokaryotic and Eukaryotic Cells

Cells, continued

Directions: Using all of the following terms in the word bank, complete the graphic organizer.

Word Bank cell DNA energy eukaryotic heredity lysosomes nucleus prokaryotic ribosomes

No 1. ______membrane-bound organelles Membrane-bound organelles

has Types are has

2.______3.______both have contains

has

contains 4. ______has DNA make 5. ______

proteins mitochondria found in

in found found

7.______nuclear region produces controls

for 8.______9 ______.

digesting material

2 Prokaryotic and Eukaryotic Cells

cells cell theory composition hereditary metabolism organelles organisms pre-existing

CLOZE 1

Robert Hooke is credited for the discovery of ______. It took over 150 years and the work of many scientists for the development of the ______.

The cell theory was developed by Theodor Schwann, Matthias Schleiden, and Rudolph

Virchow. It states that ______are the basic units of life; all living

______are composed of one or more cells; and new cells arise from ______cells. The theory further explains that cells contain

______information that is passed from cell to cell during cell division. All cells have the same basic chemical ______, and all cells have an energy flow within them called ______.

1 Prokaryotic and Eukaryotic Cells

INSTRUCTIONS: Use the words in the box below to fill in the blanks based on what you have learned about prokaryotic and eukaryotic cells. Words may be used more than once or not used at all. Word Bank atoms bacteria cells eukaryotic organelle organisms prokaryotic rod shape spherical

CLOZE 2

There are two types of cells. ______cells are simple cells that lack a membrane-bound nucleus. ______cells are more complex cells because they contain membrane-bound organelles. ______cells are much smaller than eukaryotic cells. An example of prokaryotic cells is

______. Bacteria are often classified by their

______. The bacteria that are called bacillus have a ______shape, those that are ______are called cocci, and those that are spiral are called spirochetes.

2 Prokaryotic and Eukaryotic Cells

INSTRUCTIONS: Use the words in the box below to fill in the blanks based on what you have learned about prokaryotic and eukaryotic cells. Words may be used more than once or not used at all. Word Bank cell membrane cell wall centrioles chloroplasts Golgi body lysosome mitochondria nucleus organelles vacuole

CLOZE 3

The eukaryotic cells are found in protists, fungi, plants, and animals. All plant and animal cells contain some similar ______within their cells. Each organelle has a specific function in the cell. The ______controls the activities of the cell; it acts very much like the brain of the cell. The ______produces the energy storing compound ATP. The garbage-disposal organelle in the cell is the

______because it will digest foreign material and the broken-down parts within a cell. The ______packages the materials in the cell before secreting them outside the cell. The envelope that surrounds the cell is known as the

______. Plants contain some organelles that animal cells do not have. Plants contain ______which store the green pigment called chlorophyll. Plants require large amounts of water to live; the water is stored in the large central

______. Plant cells must be rigid so they have an additional layer that surrounds the cell membrane called the ______.

3 1C.3 Viruses

The characteristics of viruses differ greatly from those of living organisms. Viruses are not cells; they contain a nucleic acid core surrounded by a protein coat and are only capable of replicating while inside of a host cell. Virus Structure & Reproduction

All viruses are surrounded by a protective coat made of proteins. They contain some form of nucleic acid, either DNA or RNA, within their protective coats. Some viruses also have binder proteins on their surface. After infecting a host cell, a virus typically splices its own nucleic acid into that of the host cell. It then uses the cell's ribosomes and organelles to make copies of all the components needed to produce more viruses. The following diagram shows three common types of viruses.

Adapted from image courtesy of the National Institutes of Health

There are two cycles of viral reproduction: the lytic cycle and the lysogenic cycle. In the lytic cycle, a virus will continue to make copies of itself until the host cell bursts. In this way, the virus is able to spread to other cells. Due to this method of reproduction, viruses can cause many diseases in living organisms. However, their ability to insert the nucleic acid they carry into a host cell (which they do during the lysogenic cycle) has made them useful tools for genetic research and gene therapy, the process of replacing a cell's defective genes with functioning ones. Viruses vs. Cells

Characteristics of Viruses • Viruses are not alive. • Viruses must use a host cell to reproduce. • Viruses do not possess organelles or ribosomes. • Viruses do not have their own energy metabolism. • Viruses are surrounded by a protein coat. • Viruses are extraordinarily small.

Characteristics of Both Cells & Viruses • Both cells and viruses contain some form of nucleic aid (DNA or RNA). • Both cells and viruses can infect host cells.

BIO 1C3 Virus Questions Question 1 .

One of the main characteristics of living things is that living things are able to reproduce. Viruses are also able to reproduce, but only by using the reproductive mechanisms of what?

A. RNA

B. a host cell

C. binary fission

D. DNA

Question 2 .

All known viruses can only reproduce inside of host cells. What is one reason why viruses must use living cells to reproduce?

A. Viruses do not have genetic material, such as DNA, that is found in living cells.

B. A virus's ribosomes require substances found in living cells to function.

C. Viruses do not have machinery, such as ribosomes, needed to make proteins.

D. A virus's nucleus does not contain the machinery needed to replicate DNA.

Question 3 .

Which description of a virus is correct?

A. A virus has no cell structure, but it has genes.

B. A virus is a non-cellular structure which replicates itself and its genes.

C. A virus is a cellular organism which transfers its genes into the host cells.

D. A virus has no genes, but it has a cell structure.

Directions: Drag each tile to the correct box.

The diagram below shows the general sizes of atoms, small molecules, proteins, viruses, prokaryotic cells, and eukaryotic cells.

Viruses are non-cellular organisms that differ in structure and complexity from prokaryotic and eukaryotic cells. Arrange the organisms shown below from largest to smallest.

viruses eukaryotic cells prokaryotic cells

> >

Question 5 .

A scientist isolates a disease-causing particle. Which of the following properties would indicate that the particle is a virus and not a bacterium?

A. an absence of cellular machinery

B. a size greater than 400 nm

C. the ability to reproduce independently

D. the presence of DNA

Question 6 .

A scientist was studying how a specific virus infects skin cells. In a lab, the scientist exposed a group of skin cells to the virus. Over time, the number of living skin cells in the group decreased.

Which statement explains why this change occurred?

A. Viruses reproduce outside of cells, creating harmful chemicals that kill the cells.

B. Viruses reproduce inside of their host cells, eventually killing the cells.

C. Viruses reproduce before they enter cells, and the new viruses infect these cells.

Both viruses and cells are able to replicate their genetic material. What is the main difference in their replication processes?

A. Viruses can replicate independently, whereas cells require assistance.

B. Viruses require host cells, whereas cells provide their own replication mechanisms.

C. Viral replication always takes longer than the replication of cellular genetic material.

D. Viral replication does not use any enzymes, whereas cells use enzymes during the replication process.

Question 8 .

Cells are the basic units of life. Viruses differ from cells in many key ways. Which of the following is true?

A. Cells contain organelles, whereas viruses do not contain organelles.

B. Cells cannot maintain homeostasis, whereas viruses can maintain homeostasis.

C. Cells contain nucleic acids, whereas viruses do not contain nucleic acids.

D. Cells do not contain ribosomes, whereas viruses do contain ribosomes.

Question 9 .

The diagram below shows two different types of life cycles that occur at the microscopic level. Each shows a single occurrence of a life cycle.

Which of the following is true?

A. Both life cycle X and life cycle Y must represent virus life cycles because only viruses can reproduce

B. Life cycle Y must represent a virus life cycle because a host cell is required for reproduction.

C. Life cycle X must represent a virus life cycle because it is able to reproduce by splitting in two.

D. Neither life cycle X nor life cycle Y can represent a virus life cycle because both result in multiple offspring.

Which of the following statements regarding the genetic material of cells and viruses is true?

A. The nucleotides found in cells are different from the nucleotides found in viruses.

B. The characteristics of cells are encoded in genes, but viruses do not have their own genes.

C. Viral genes may be encoded by DNA or RNA, but cellular genes are always encoded by DNA.

D. The genes of both viruses and cells are enclosed within a nucleus.

Question 11 .

Both viruses and cells contain

I. nuclei. II. genetic material. III. mitochondria. IV. cell membranes.

A. II and III only

B. I, II, III and IV

C. I and II only

D. II only

Question 12 .

Which of the following best describes viral reproduction?

A. The genetic material of a virus enters a living host cell and combines with the cell's nucleotides in order to form a hybrid cell that is capable of asexual reproduction.

B. The chromosomes of a virus line up and condense into rod-like structures inside of the virus's capsid, then slowly divide as a viral envelope forms around each chromosome.

C. The genetic material of a virus enters a living host cell and takes over the translational and transcriptional mechanisms of the cell in order to replicate the virus's nucleic acids.

D. The chromosomes of a virus replicate themselves inside of the virus's capsid, then line up and slowly divide as a viral envelope forms around each set.

A virus reproduces by

A. binary fission.

B. releasing spores.

C. converting RNA to DNA.

D. taking over host cells.

Question 14 .

The image below shows a virus and a cell with some of their features labeled.

What is one way that the structure of a virus differs from that of a cell?

A. Viruses do not have organelles needed to replicate.

B. Viruses do not have their own genetic material.

C. Viruses do not have molecules that interact with cells.

D. Viruses do not have a protective outer covering.

Question 15 .

Both viruses and cells are able to replicate their genetic material. What is the main difference in their replication processes?

A. Viral replication always takes longer than the replication of cellular genetic material.

B. Viral replication does not use any enzymes, whereas cells use enzymes during the replication process.

C. Viruses can replicate independently, whereas cells require assistance.

D. Viruses require host cells, whereas cells provide their own replication mechanisms.

1. B

2. C

3. A

4. --

5. A

6. B

7. B

8. A

9. B

10. C

11. D

12. C

13. D

14. A

15. D

Viral Replication and Treatment

1 Viruses have been in the news alot lately, from the West Nile virus, to H1N1, to the bird flu. But, what exactly is a virus, and why is there such concern over the spread of these pathogens? The concern has to do with the structure and reproductive cycle of these disease-causing agents. Viruses are not structured Like other biological organisms. In fact, viruses are not considered biological organisms at all. Let us take a closer look at the structure and reproductive systems of viruses. Then we can discuss why these factors make viruses so difficult to treat.

2 Most biological cells consist of a membrane that encloses genetic material in the form of a double-helix strand of DNA. This is true whether the cell is a prokaryotic bacteria, or a eukaryotic cell in a plant, animal, fungus, or protist. Viruses are different. First of all, viruses do not have cell membranes. The material inside the virus is enclosed in a protein shell called a capsid. Within the capsid is another structure called the viral envelope. Second, viruses do not always contain a double-helix strand of DNA. The genetic material inside the virus can come in a variety of forms, from a single strand of DNA to a strand of RNA. Third, viruses have no mechanisms for metabolism. They also do not have ribosomes. But, what truly distinguishes viruses from other biological structures is that viruses cannot replicate on their own. They can only reproduce within another cell, or a host cell. This is why many do not consider viruses to be living cells at all.

3 Viruses do not have metabolism, while all bacteria and other cells do. Also, viruses (unlike other biological cells) rely on other organisms to survive and replicate. They are considered a type of parasite because they need another organism to survive. Let us look at a specific type of virus, the bacteriophages, or phages. These types of viruses infect bacteria and are highly structured. Their replication methods are well documented. There are two main ways that these types of viruses can replicate within a host organism. Both of these methods make it very difficult to treat and destroy the virus once it has entered the host cell.

4 The first type of replication cycle seen in phages is the lytic cycle. Let us assume that this virus is infecting an E. coli bacterium. The phage has specific structures that fit into receptors on the plasma membrane of its host cell. It will land on the surface of the E. coli and inject its genetic material straight into the cell. The genetic material of the virus will form a circle and take control of the protein synthesis “machinery” of the host cell.

1 Viruses

At this point, the new genetic material will direct the host cell to start replicating viral parts from the host cell’s molecules. The viral components will be replicated in pieces. They will then assemble within the cell. Once the cell produces 100 to 200 phage products, the cell will burst (lyse). This kills the host cell and releases the newly formed viruses, which will then infect other nearby cells.

5 The second type of replication cycle is the lysogenic cycle. In this cycle, the host cell is not killed. Instead, it is used to produce more of the viral genome. As with the lytic cycle, the virus will attach to the host’s receptors and release its genetic information into the host cell. However, the viral genome will then become incorporated into the host cell’s genome. Host cells with embedded viral genomes are called lysogens. Each time the host cell reproduces, it copies the viral genome and passes this information to each daughter cell. In this way, the information for creating more viruses is carried in a host organism without killing the host organism. However, at certain points, the viral replication cycle can switch from lysogenic to lytic and back again.

5 The viral replication cycle is the reason that viruses are so difficult to treat. Once the host cells are infected with the viral genetic material, it is almost impossible to remove. In other words, viral infections can not currently be cured. They can, however, be treated with medicines to lessen the symptoms. Often, certain lymphocytes in the body’s immune system make enough antibodies to destroy more viruses than are being made. In this way, the disease is overcome. Sometimes viral infections can be prevented by immunizations or vaccines. People are exposed to pieces of specific disease-causing viruses. The body’s immune system is triggered to prepare to fight the actual specific virus if it encounters one in the future. This is why many people in the United States are vaccinated against such viral diseases as chicken pox, the measles, and the flu. Unfortunately, HIV, the human immunodeficiency virus, infects and causes the death of the very cells that form antibodies to protect you. That is why people who are infected with HIV become sick due to infections that otherwise healthy people could successfully fight.

2 Viruses

1 In which replication cycle is the viral genome reproduced without damage to the host cell?

A The lytic cycle

B The attachment cycle

C The parasitic cycle

D The lysogenic cycle

2 Which of the following statements is false?

A Viruses have metabolism.

B Viral infections can be prevented with vaccines.

C Viruses are a type of parasite.

D Viral replication cycles can switch from lysogenic to lytic and back again.

3 Considering the information given in paragraph 1, we know that viruses —

A are all of the following.

B are disease-causing pathogens.

C are not considered biological organisms.

D cause a great deal of concern.

3 Viruses

4 A virus is a pathogen that contains several components. Which of the following could NOT be a component of a virus?

A A strand of RNA

B A protein shell

C A ribosome

D A viral envelope

5 How do immunizations work with viruses?

A They cure the person by killing the virus cells and preventing the symptoms.

B They show the body virus pieces to prepare it to fight that virus in the future.

C They treat all of the symptoms of the virus so that they are not as severe.

D They provide a chemical that keeps any virus from infecting the cells.

6 What is the main reason that viruses are not considered to be living organisms?

A They are too small to be living.

B They do not have DNA.

C They need the host cell to replicate.

D They kill the host cells.

4 Viruses

7 Why is the human immunodeficiency virus so deadly?

A It cannot be broken into pieces to make antibodies.

B It is too small to identify the white blood cells.

C It is not recognized as a virus by the body.

D It kills the cells that make antibodies.

5 Viruses

INSTRUCTIONS: Use the words in the box below to fill in the blanks based on what you have learned about viruses. Words may be used more than once or not used at all.

Word Bank capsid DNA facultative microscope non living nucleic acid obligate protein reproduce RNA

CLOZE 1

A virus is ______because it does not possess all the characteristics of

living things. A virus is unable to ______on its own; it must be within

a host cell. Because a virus cannot live independently of a host, it is considered to be a

______parasite. The structure of a virus consists of only one type of

______that is surrounded by a protein coat called an

______. Viruses cannot be seen by a compound light

______because they are so small.

1 Viruses

INSTRUCTIONS: Use the words in the box below to fill in the blanks based on what you have learned about viruses. Words may be used more than once or not used at all.

Word Bank burst lysis lysogenic cycle lytic cycle not living nucleic acid reproduce shrivel

CLOZE 2

When a virus reproduces within a host, it undergoes one of two processes. It can replicate itself, causing the cell to ______, releasing many viruses into the body to attack more cells. The scientific name for a cell bursting is called ______; therefore, this type of viral reproduction is called the ______. In the other type of reproductive process, the virus will remain dormant in the body by incorporating its nucleic acids with the cell’s nucleic acids in the

______.

2 Viruses

INSTRUCTIONS: Use the words in the box below to fill in the blanks based on what you have learned about viruses. Words may be used more than once or not used at all.

Word Bank antibiotics bacteriophages cure diseases HIV inhibiting retroviruses RNA tumor viral

CLOZE 3

Because viruses are parasitic to an organism, they cause ______when they infect a cell. There are many types of viruses. Some viruses have been known to transform a cell into a cancer cell, resulting in the organism forming a

______. Viruses that attack bacteria are known as

______. Some viruses contain RNA instead of DNA; these viruses are called ______. One of the most dangerous retroviruses that is well-known in the United States is the ______virus. Chemicals can be used to help control the viral replication of the HIV virus by ______the reverse transcriptase and preventing the RNA from being transcribed into DNA. Although chemicals such as AZT help to control the virus, the chemical is not a ______.

Viruses cannot be cured by ______.

3 BIO 1D Cell Transport

In order for cells to function properly, they must be able to transport materials, such as water and nutrients, in through their cell membranes, and they must be able to transport materials, such as wastes and excess substances, out through their cell membranes.

Materials can enter and exit through the cell membrane by passive transport and active transport. The Cell Membrane

The cell membrane, or plasma membrane, is made up of phospholipid molecules. These molecules have a hydrophilic ("water-loving") head and a hydrophobic ("water-fearing") tail. The hydrophilic heads face outward, and the hydrophobic tails face inward.

This arrangement causes the cell membrane to be semi-permeable. That is, only some substances can pass directly through the cell membrane.

The cell membrane controls the movement of substances into and out of the cell. Passive Transport

Passive transport is a type of cell transport that does not require the cell to expend energy. Diffusion, facilitated diffusion, and osmosis are types of passive transport. • Diffusion, or simple diffusion, involves the movement of material along a concentration gradient. That is, materials move across the cell membrane from an area of high concentration to an area of low

concentration.

Diffusion will continue across a semi-permeable membrane until particles are equally concentrated on both sides of the membrane. Small molecules, such as oxygen, ethanol, and carbon dioxide, easily diffuse across membranes.

• Some molecules cannot simply diffuse across the cell membrane because they are too large or because they have a chemical structure that prevents them from passing directly through the cell membrane.

Facilitated diffusion is a type of diffusion that uses special transport proteins to transfer molecules across cell membranes. Like diffusion, facilitated diffusion involves the movement of material along a concentration gradient, so no energy is required.

Image courtesy of Wikipedia Glucose is an example of a molecule that is transported by facilitated diffusion.

• Osmosis is a type of diffusion that specifically involves the movement of water across a semi-permeable membrane. During osmosis, water moves from areas of high concentration to areas of low concentration, so energy is not expended.

Cells react differently when placed in solutions with different concentrations.

When the water concentration is the same on the inside and outside of a cell, there is no net movement of water.

When the water concentration is greater inside the cell than it is outside of the cell, water moves out of the cell, and the cell shrivels.

When the water concentration is greater outside of the cell than it is inside the cell, water moves into the cell, and the cell may burst, or lyse. Lysis occurs more frequently in animal cells than plant cells, since animal cells do not have a cell wall. Active Transport

Active transport is a type of cell transport that requires a cell to expend energy. Active transport typically occurs when substances try to move against a concentration gradient (i.e., from an area of low concentration to an area of high concentration) or when molecules are too large to undergo facilitated diffusion. Cell membrane pumps, endocytosis, and exocytosis are types of active transport. • Cell membrane pumps are protein molecules that are embedded in the cell membrane. These molecules use energy to pump substances across the cell membrane against the concentration gradient.

The sodium-potassium pump is an example of a cell membrane pump. The sodium-potassium pump is found in almost all animal cells, and it plays a vital role in transporting nerve impulses.

Image courtesy of Wikipedia • Endocytosis is the process through which large molecules are transported into a cell. During endocytosis, the cell membrane surrounds a molecule and forms a vesicle. The vesicle then pinches off of the cell membrane, so its contents can be released inside of the cell.

• Exocytosis is the process through which large molecules are transported out of a cell. During exocytosis, a molecule is packaged into a vesicle. Then, the vesicle fuses with the cell membrane and expels its contents outside of the cell.

The Cell Membrane & Osmosis

In order for a cell to function properly, the cell membrane controls what goes in and out of the cell. The Cell Membrane & Homeostasis

Through cellular activities and responses, organisms can maintain internal stability in a wide range of external conditions. This process is called homeostasis. One of the features that allows cells to perform their necessary activities is their selectively permeable (or semipermeable) cell membranes. These membranes are located beneath the cell walls of plant cells, and they form the outer boundary of the cell in animal cells. The semi-permeability of the membrane permits cells to control what comes into the cell and what goes out. In this way, they take in nutrients and other materials and expel wastes and cell products. The Lipid Bilayer & the Fluid Mosaic Model

Two layers of phospholipid molecules form the lipid bilayer of the cell membrane.

A structure called the lipid bilayer makes up the vast majority of the cell membrane. The lipid bilayer is formed from two layers of phospholipids and has a unique structure: the hydrophilic ("water-loving") heads of the phospholipids face outward (toward the exterior and interior of the cell), and the hydrophobic ("water-fearing") tails face inward. This arrangement allows the cell membrane to control the movement of substances in and out of the cell. In fact, due to this arrangement, polar molecules or large nonpolar molecules are unable to go across the cell membrane unless they pass through special protein channels, or their diffusion must be facilitated by carrier proteins.

The cell membrane is composed of lipids, proteins, and carbohydrates.

The structure and function of a cell membrane is described by the fluid mosaic model. According to this model, the membrane is like a mosaic because it is made up of many different parts, including different types of carbohydrates, proteins, and lipids. Also, according to this model, the membrane is considered to be fluid because the structures within the membrane can move. Osmosis & Homeostasis

Water is an essential component of plant and animal materials and crucial for the maintenance of homeostasis in the cell. It provides a soluble environment for chemical processes, serves as a reactant in some chemical reactions, and provides hydration that maintains cell shape. Osmosis is a type of diffusion that specifically involves the movement of water across a selectively permeable membrane. During osmosis, water moves from areas of high concentration to areas of low concentration, so energy is not expended.

When concentrations of solute molecules, such as salt or sugar, are not the same on both sides of the cell membrane, water will move across the barrier until the concentration of solutes is balanced. This is the basic mechanism of osmosis. Cells can be in one of three different osmotic states depending on their environment, as shown below.

• A hypertonic solution is one in which the water concentration outside the cell is lower than the water concentration inside the cell, so water leaves the cell more rapidly than it enters. This causes the cell to lose volume and shrivel.

When a cell is placed in a hypertonic solution, the net movement of water is out of the cell.

Both plant and animal cells are negatively impacted by hypertonic environments. More specifically, plant cells experience plasmolysis, or wilting, which can kill the plant. • An isotonic solution is one in which the aqueous environment around a cell has the same concentration of water as the cell. As a result, water flows into the cell at the same rate that it flows out, so the size and shape of the cell does not change.

When a cell is placed in an isotonic solution, there is no net movement of water.

Animal cells thrive in isotonic solutions because the balance of water aids the cell in energy production and waste removal. In contrast, plant cells tend to become limp, or flaccid, in isotonic solutions. • A hypotonic solution is one in which the water concentration outside the cell is higher than the water concentration inside the cell, so water enters the cell more rapidly than it leaves.

When a cell is placed in a hypotonic solution, the net movement of water is into the cell. Because they lack the extra support provided by a cell wall, hypotonic solutions cause animal cells to eventually lyse, or rupture. A plant cell, on the other hand, thrives in a hypotonic environment. The cell wall is able to contain the turgid (very firm) plasma membrane. This helps plants support the weight of their stems and stalks.

BIO 1D Question 1 .

Homeostasis refers to the necessity of an organism to maintain constant or stable internal conditions. What structure helps cells maintain homeostasis by regulating the movement of materials into and out of a cell?

A. mitochondrion

B. cell membrane

C. chloroplast

D. nuclear membrane

Question 2 .

Directions: Select ALL the correct answers.

Which of the following statements correctly describes the function of the cell membrane?

synthesizes proteins for the cell

prevents harmful materials from entering the cell

regulates uptake of materials needed by the cell

removes waste materials from the cell

creates energy used by the cell

Question 3 .

Directions: Select the correct image.

The images below show red blood cells surrounded by three different solutions. Each solution was prepared by adding a different amount of a particular solute (sodium chloride) to pure water. In which image is the concentration of solute outside the cells about the same as the concentration of solute inside the cells?

In carrying out normal activities, cells use oxygen and produce carbon dioxide. The concentration of oxygen is higher in the blood than inside the cell, so oxygen moves into the cell. Similarly, carbon dioxide moves out of the cell into the blood because the concentration of carbon dioxide inside the cell is greater than the concentration outside the cell.

How do the small molecules of oxygen and carbon dioxide move through the cell membrane?

A. active transport by endocytosis

B. passive transport by osmosis

C. active transport by carrier proteins

D. passive transport by diffusion

Question 5 .

Directions: Select the correct image.

The images below show red blood cells surrounded by three different solutions. Each solution was prepared by adding a different amount of a particular solute (sodium chloride) to pure water. In which image is the concentration of solute outside the cells greater than the concentration of solute inside the cells?

Question 6 .

In animals, glucose is absorbed from the gut into intestinal cells against its concentration gradient. This one-way process requires energy to work. Which of the following best describes how glucose is absorbed into intestinal cells?

A. by diffusion

B. by a buffer

C. by active transport

D. by osmosis

Cells use ______to take in large molecules or other cells.

A. passive transport by osmosis

B. active transport by carrier proteins

C. active transport by endocytosis

D. passive transport by diffusion

Question 8 .

If the water concentration inside a cell is higher than the water concentration outside the cell, water flows out of the cell. This method of molecular transport is called

A. exocytosis.

B. a sodium pump.

C. osmosis.

D. endocytosis.

Question 9 .

Examine the following diagrams of plant cells. Each cell has been placed in a different solution.

1 2 3

The cell in diagram 2 has been placed in a solution that contains ______the interior of the cell.

A. water that is warmer than

B. a lower concentration of water than

C. water that is cooler than

D. the same concentration of water as

The diagram below shows plant cells submerged in solutions with different concentrations of sugar.

In diagram 2, water is flowing by osmosis both into and out of the cell because the concentration of water

A. inside the cell is higher than in the surrounding solution.

B. is the same both inside and outside the cell.

C. forces waste products to leave the cell.

D. inside the cell is lower than in the surrounding solution.

Question 11 .

In a laboratory, red blood cells are placed into a solution of water and sodium chloride. The concentration of sodium chloride inside of the red blood cells is lower than that in the solution. Which of the following will most likely to happen to the red blood cells?

A. The cells will not change because the net flow of water will be zero.

B. The cells will burst because there is no change in osmotic pressure.

C. The cells will shrink because the net flow of water will be from the cells into the solution.

D. The cells will swell because the net flow of water will be from the solution into the cells.

Question 12 .

Directions: Select the correct image.

The images below show red blood cells surrounded by three different solutions. Each solution was prepared by adding a different amount of a particular solute (sodium chloride) to pure water. In which image is the concentration of solute outside the cells less than the concentration of solute inside the cells?

Active transport requires energy because it usually involves the movement of

A. substances that can easily pass through the cell membrane, such as water.

B. substances in the gas phase, such as oxygen and carbon dioxide.

C. substances from an area of high concentration to an area of low concentration.

D. substances from an area of low concentration to an area of high concentration.

Question 14 .

Look at the diagram below.

The yellow oval represents a cell with a semi-permeable membrane. The small, black dots represent molecules of water, and the larger, blue dots represent a solute such as sugar or salt. The membrane allows small molecules such as water to pass through, but it does not allow larger molecules such as solute to pass.

What will happen to the substances in this diagram to bring the concentrations closer to equilibrium?

A. Water will flow out of the cell and into the surrounding environment.

B. The solute will flow into the cell from the surrounding environment.

C. Nothing will change because it is already in equilibrium.

D. Water will flow into the cell from the surrounding environment.

The following diagram is a model of the cell membrane. Though small, nonpolar molecules are usually able to pass freely across the cell membrane, larger molecules and ions can only enter and exit cells through carrier proteins or channel proteins.

Using the model above for reference, what effect would the removal of carrier proteins likely have on cell transport?

A. The number of protein channels in the membrane would increase.

B. The movement of glucose molecules into the cell would decrease.

C. The concentration of glucose molecules outside of the cell would decrease.

D. The movement of sodium ions out of the cell would increase.

Question 16 .

Cell membranes (plasma membranes) help organisms maintain homeostasis by controlling what substances may enter or leave cells. Some substances can cross a cell membrane through passive transport, while other substances can only cross a cell membrane through active transport. What is the difference between active and passive cellular transport?

A. Active transport is the only form of transport that requires the use of protein carriers.

B. Active transport requires the cell to expend energy, while passive transport does not.

C. Passive transport is the only form of transport that requires the use of protein carriers.

D. Active transport requires the cell to form vesicles, while passive transport is done through osmosis.

Question 17 .

Living organisms are only able to function and thrive if they can maintain constant or stable internal conditions. This ability is known as ______.

A. cell differentiation

B. homeostasis

C. endocytosis

D. natural selection

The fluid mosaic model shown above describes the structure and function of

A. chloroplasts.

B. chromosomes.

C. cell membranes.

D. nuclei.

1. B

2. --

3. --

4. D

5. --

6. C

7. C

8. C

9. D

10. B

11. C

12. --

13. D

14. A

15. B

16. B

17. B

18. C

Multicellular organisms possess many different types of cells. These different cell types carry out specialized functions that are necessary in order for the organism to survive. The process by which a cell becomes specialized is known as cell differentiation. Cells Vary in Shape & Size

All organisms are made of cells. Although most are fairly small and can often only be seen with the aid of a microscope, cells do vary in shape and size. Bacteria, for example, may be only one to ten micrometers in diameter. Animal cells tend to be approximately ten to thirty micrometers in diameter. Plant cells tend to be larger than animal cells, and they generally range from ten to one hundred micrometers in diameter.

Living cells vary in size, shape, and function. Several different types of cells are shown here. Specialized Cells Cooperate

In unicellular organisms (organisms that consist of a single cell), all of the tasks needed for the organism to survive can be carried out by its one cell. But in complex, multicellular organisms, different cells are needed to perform different, specialized functions.

Having many different kinds of cells that each specialize in a different process allows multicellular organisms to perform many different functions more efficiently and at the same time. The cells of multicellular organisms can even send chemical signals to one another to help coordinate their actions. Cell Division & Differentiation

In sexually-reproducing organisms, such as humans, offspring are formed when a sperm cell unites with an egg cell during fertilization. The fertilized egg, or zygote, then undergoes several cycles of cell division until a large ball of identical cells is produced. Eventually, the large ball of identical cells undergoes cell differentiation (also called cell specialization). During this process, cells become specialized to perform different functions.

Cell differentiation is responsible for the many different types of cells found in multicellular organisms. Embryonic Development

As it continues to divide, the mass of cells, now called an embryo, goes through several developmental stages. At the gastrula stage, two cavities form in the embryo, and three different types of cells can be observed there—the ectoderm, the mesoderm, and the endoderm.

These three types of cells form the primary germ layers. The cells in these three layers later differentiate further into the highly specialized types of cells that make up a complete organism— muscle, nerve, blood, bone, and skin cells.

• The cells of the ectoderm differentiate to form the skin and nervous system of the organism.

• The cells of the endoderm eventually become the organism's digestive tract lining.

• The cells of the mesoderm become the organism's muscles, blood, and reproductive organs. The Role of DNA in Cell Differentiation

With very few exceptions, the DNA contained in every cell of a multicellular organism is exactly the same. How is it possible, then, for the cells of an organism to vary so widely in size, shape, and function? Cell differentiation is usually due to different cells exhibiting different patterns of gene expression. Gene expression is the process by which DNA is made into a functional gene product, such as RNA or a protein. Although each of an organism's cells contains the same DNA, some of the cell's genes have been activated (essentially, turned on), while others have been deactivated (turned off). This means that, in all mature cells, only a portion of the entire genome of an organism is expressed at any given time. Undifferentiated cells are called stem cells, and all stem cells have the potential to develop into any kind of body cell. Once a cell differentiates, however, all of its descendants will be of the same type and have the same activated genes.

So, what causes a cell to differentiate? Although the mechanisms involved in cell differentiation are complex, the process begins when hormones and other signaling molecules are received by the cell from other cells and from the organism's environment. These signals influence gene expression in the cell, resulting in dramatic changes to the cell's size, shape, metabolic activity, and responsiveness to new signals. Examples of Differentiated Cells

Different types of cells often look very different, but the size and shape of each cell helps it perform its specialized role in the body. The list below discusses some examples of differentiated cells and their functions. • Nerve cells relay electrochemical signals to other cells. The structure of a nerve cell allows the cell to more easily send and receive signals to and from all parts of the body. • Red blood cells carry oxygen to all parts of the body as they move in the blood stream. The smooth, round shape of red blood cells allows the cells to flow smoothly through blood vessels. Mature red blood cells do not possess a nucleus, which increases the amount of oxygen they can carry. • White blood cells are many times larger than red blood cells. They are equipped with a number of capabilities that help them fight disease in the body. • Muscle cells help the body move. These cells have a long, thin shape and structures that allow the cells to shorten or lengthen as they contract or relax. • Fat cells store fat until it is needed. These cells have large storage spaces that can expand to hold large amounts of fat. • Bone cells have rigid shapes that lock with other bone cells. This extra strength gives the body support and a place for muscles to attach. • Skin cells protect and cover the body. They are often flat in shape and work with nerve cells to receive signals from the external environment. • Reproductive cells, such as sperm and egg cells, allow sexually-reproducing organisms to pass genetic information to their offspring.

BIO 1E Cell cycle Question 1 .

At a point during a cell's development, it begins to differentiate. How does differentiation occur?

A. The number of chromosomes in the cell is reduced by half; this action triggers the specialization of the cell.

B. Certain genes are turned on and others are turned off; this action produces adult cells that are specialized.

C. As a cell matures, genes that are not necessary to its function are ejected out of the cell through active transport.

D. A developing cell's function is determined by the number of organelles that are contained in the cell.

Question 2 .

A diagram of the cell cycle is shown below.

Which of the following statements best describes what happens during the S phase of the cell cycle?

A. The cell's chromosomes separate.

B. The contents of the cell divide.

C. The cell's DNA is replicated.

D. The cell prepares for mitosis.

Question 3 .

During which stage of the cell cycle does the cell replicate (copy) its DNA?

A. meiosis

B. cytokinesis

C. mitosis

D. interphase

Body cells are known as somatic cells.

How does one somatic cell compare to the other somatic cells of an individual organism?

A. They contain the same genetic information and descend from the same cell.

B. They contain completely unique information and descend from the same cell.

C. They are all exactly identical to each other.

D. They are all completely different from each other.

Question 5 .

The diagram below shows the process of mitosis.

Mitosis is a form of

A. cell division.

B. cell fertilization.

C. cell differentiation.

D. cell specialization.

Question 6 .

Cancer is a disease that usually results when

A. a person has a severe allergic reaction.

B. a bacterium enters the body through a person's skin.

C. mutations cause a person's body cells to divide uncontrollably.

D. a person has limited exposure to sunlight.

An animal was injured while hunting for prey. The animal's body needs to produce more cells to heal the injury. How will this happen?

A. New cells are produced through meiosis, where only half of the chromosomes were copied, so the cells are different from each other.

B. New cells are produced through mitosis, where each chromosome was copied exactly, so the cells produced are identical to each other.

C. New cells are produced through meiosis, where each chromosome was copied exactly, so the cells produced are identical to each other.

D. New cells are produced through mitosis, where only half of the chromosomes were copied, so the cells are different from each other.

Question 8 .

The following diagram shows the processes of fertilization and cell specialization.

Which of the following statements is implied by the diagram?

A. Specialized cells are produced immediately following fertilization, or the fusion of a sperm cell with an egg cell.

B. Specialized cells, such as bone cells, skin cells, red blood cells, and muscle cells, cannot be produced from a single cell.

C. Even though all the cells in an individual organism come from a single cell, they can specialize into different types of cells.

D. Since all of the cells in an individual organism come from a single cell, they must all be identical.

In sexually-reproducing organisms, a sperm cell unites with an egg cell during fertilization.

Then, the fertilized egg, or zygote, undergoes ______to form a massive ball of identical cells. Finally, the cells become specialized in structure and function through the process of ______.

A. cell differentiation; cell division

B. cell division; cell differentiation

C. mitosis; meiosis

D. meiosis; mitosis

The following diagram shows how cells differentiate after fertilization.

Which of the following best describes how a wide variety of specialized cells can originate from the same undifferentiated mass of cells?

A. All cells contain the same DNA, but only specific parts of the DNA are activated to determine a cell's specialization.

B. Cells can change from one specialization to another depending on the needs of the organism.

C. After fertilization and cellular division, each cell contains different DNA which forms a different type of specialized cell.

D. Each type of specialized cell is contained within the sex cells before fertilization occurs.

Directions: Drag each tile to the correct box.

The stages of mitosis are shown below, but they are not in the correct order. Arrange the stages in the order they occur.

↓

Question 12 .

Which of the following provides the best evidence for the idea that multicellular organisms are composed of highly organized arrangements of differentiated cells?

A. A frog cell obtains energy from the bonds of food molecules through cellular respiration.

B. The chloroplasts of a plant cell capture light energy that can be used to make food.

C. Sheets of bone cells in a rabbit's body are connected to muscle cells that allow movement.

D. A mouse cell divides into two identical daughter cells through the process of mitosis.

Examine the graph below.

According to the graph, what happens once cells reach a certain size?

A. The cell releases fluid, so it can shrink in size.

B. The cell divides to become two smaller cells.

C. The cells fuse to become one large cell.

D. The cell dies, and two new cells spontaneously appear.

Question 14 .

Examine the picture of the two plants below:

The plant on the left is the parent plant. The plant on the right is the parent's offspring. The offspring is genetically identical to the parent. How did the parent plant reproduce?

A. The plant reproduced through asexual reproduction.

B. The plant reproduced through both asexual and sexual reproduction.

C. The plant reproduced through sexual reproduction.

D. There is not enough information to tell how the plant reproduced.

The diagram below shows a bacterial cell undergoing binary fission.

Which of the following statements best demonstrates that genetic continuity is maintained during binary fission?

A. The offspring produced through binary fission are also able to reproduce asexually.

B. Binary fission is a form of reproduction that results in two unicellular organisms.

C. The offspring produced through binary fission are identical to each other and to the parent organism.

D. Binary fission is a form of reproduction that allows an organism to reproduce without needing to find a mate.

Question 16 .

Extra tissue has formed in an organism due to uncontrolled cell growth. Which of these most likely caused the extra tissue to form?

A. The organism experienced a growth spurt.

B. The organism suffered an injury.

C. A mutation occurred in the genes that control cell division.

D. A mutation occurred that caused an increased rate of cell death.

The cytoplasm and two nuclei that are formed during mitosis are separated into two identical daughter cells during ______.

A. meiosis

B. interphase

C. prophase

D. cytokinesis

Question 18 .

A skin cell has just divided. In which order will its daughter cells undergo the next steps of the cell cycle?

A. separation of chromosomes → cell growth and DNA replication → separation of cell contents

B. separation of cell contents → separation of chromosomes → cell growth and DNA replication

C. cell growth and DNA replication → separation of cell contents → separation of chromosomes

D. cell growth and DNA replication → separation of chromosomes → separation of cell contents

Question 19 .

The elephant has 56 chromosomes in its body cells. When the elephant's body cells divide by mitosis, how many chromosomes will each daughter cell have?

A. 56

B. 168

C. 28

D. 112

Examine the diagram below:

Ciliates are protists that are able to reproduce both sexually and asexually. Both of these forms of ciliate reproduction are shown in the diagram.

Which type of reproduction is represented in Process A?

A. budding

B. sexual reproduction

C. fission

D. fragmentation

Question 21 .

Due to a mutation, an autosomal cell in a multicellular organism does not receive the normal signal to stop dividing. What effect will this most likely have on the organism?

A. Its cells will become inactive.

B. It will experience tumor growth.

C. It will age at an increased rate.

D. It will be unable to reproduce.

Question 22 .

During the cell cycle,

A. DNA is replicated directly after the completion of mitosis.

B. DNA is replicated before mitosis begins.

C. DNA is replicated during mitosis.

D. DNA is replicated once before mitosis and again before cytokinesis.

During fertilization in multicellular organisms, a sperm cell fuses with an egg cell to form a zygote. Then, the zygote begins to divide. First, one cell becomes two, then two cells become four, four cells become eight and so on and so forth until a large ball of identical cells is formed.

At this point, the ball begins to change. A space forms in the middle, and the cells are pushed inward to form layers.

If cell differentiation begins after this phase, what most likely triggers this process?

A. the formation of the layers

B. the fusion of a sperm cell with an egg cell

C. the division of the zygote into two cells

D. the division of four cells into eight cells

Question 24 .

The metaphase plate is an imaginary plane along which the centromeres of sister chromatids line up during the early stages of mitosis. A condition called failed alignment occurs when a pair of sister chromatids do not line up on this plate. What is the most likely result of failed alignment during mitosis?

A. The daughter cells will each have several chromosomes that the parent cell did not have.

B. The daughter cells will each be one half of their expected size.

C. One daughter cell will have an extra chromosome, and one will have an absent chromosome.

D. One daughter cell will be functional, and one will be nonfunctional.

Question 25 .

Directions: Select each correct answer. More than one answer may be correct.

Mitosis is a form of cell division in which one cell divides into two new cells. Each new cell has the same number of chromosomes as the original cell. In which of the following processes does mitosis play a vital role?

the production of additional embryonic cells following fertilization

the production of new body cells to replace old cells

the production of gametes for sexual reproduction

Cell division is an example of cellular ______, whereas cell differentiation is an example of cellular ______.

A. development; respiration

B. growth; development

C. respiration; reproduction

D. development; reproduction

Question 27 .

Strawberry plants reproduce by forming stems, or runners, that grow along the ground.

At random intervals along the runner, a new strawberry plant grows. Each new plant is an exact copy of the original plant and has its own roots, leaves, and stems, even though it may still be connected to the original plant by the runner.

This form of asexual reproduction is known as

A. budding.

B. vegetative propagation.

C. mitosis.

D. binary fission.

Question 28 .

Cancer, of all types, is an increasing public health concern. Which of the following best explains what causes cancer?

A. mutations in DNA that codes for proteins that regulate the cell cycle and cell growth

B. crossing over of homologous chromosomes during meiosis

C. the process of asexual reproduction and the resulting diploid cells

D. the formation of haploid daughter cells during mitosis

Some starfish have the ability to shed their arms to escape a predator. If left undisturbed, a shed arm may regrow through cell division into a complete starfish. What form of reproduction is this?

A. binary fission

B. budding

C. vegetative propagation

D. regeneration

Question 30 .

Which of the following correctly describes a type of reproduction?

A. Budding is a type of sexual reproduction.

B. A genetic copy of an organism is made during sexual reproduction.

C. Binary fission is a type of asexual reproduction.

D. Meiosis occurs during the process of asexual reproduction.

Question 31 .

Cells contain specialized parts, known as organelles, to perform specific tasks, such as waste disposal, protein building, and movement. Even though these basic cellular functions occur in all cells,

A. all cells do not perform the same exact functions in multicellular organisms.

B. all cells do not perform the same exact functions in unicellular organisms.

C. the cellular components are not at all related to the overall function of the cell.

D. the cells in unicellular organisms and all the cells in multicellular organisms must perform the same functions.

Question 32 .

Cytokinesis is a process that occurs during the cell cycle. During cytokinesis,

A. the chromosomes of the cell are duplicated.

B. the cytoplasm is divided to form two separate cells.

C. the nuclear material of the cell is divided.

D. the cell grows and performs normal life processes.

All sexually reproducing organisms begin their life cycle as a single cell—a zygote. In multicellular organisms, the zygote divides through the process of mitosis to form the embryonic body.

The diagram below shows the gastrula stage in the embryological development of a sheep.

Three distinct layers are present in the gastrula stage

the endoderm the mesoderm the ectoderm

These layers develop into specific cells within the body through the process of ______.

A. cell implantation

B. cell differentiation

C. fertilization

D. meiosis

The images below show four steps of a single process.

Which of the following sentences would make the most accurate caption for the process shown above?

A. asexual reproduction through budding

B. two gametes fusing to form a fertilized egg

C. meiosis for reproduction through fragmentation

D. asexual reproduction through binary fission

Question 35 .

Through what process do cells become specialized so they can perform specific functions within organisms?

A. differentiation

B. fertilization

C. binary fission

D. mitosis

Question 36 .

Before a cell enters mitosis, what happens to the genetic information in that cell?

A. The information is halved.

B. The information is selectively mutated.

C. The information is duplicated.

D. The information is completely changed.

An apple farmer has found an apple tree that is producing delicious apples with perfect characteristics. How can the farmer reproduce the exact same characteristics in future trees?

A. Take seeds from a variety of trees and plant them in the same type of soil as the original tree.

B. Use plant striking, a type of asexual reproduction in which a part of the parent plant is removed and planted to produce a new plant.

C. Take seeds produced by that apple tree, and plant them next to the parent tree.

D. Either asexual or sexual reproduction will produce a tree with identical apples.

Question 38 .

Multicellular organisms can consist of hundreds or even trillions of cells. Which of the following is the same for nearly every cell that makes up a particular multicellular organism?

A. specialized function

B. cellular size

C. cell type

D. DNA sequence

Question 39 .

A diagram of the cell cycle is shown below.

Which of the following statements best describes what happens during the G1 phase of the cell cycle?

A. The cell prepares for mitosis.

B. The contents of the cell divide.

C. The cell synthesizes proteins.

D. The cell's DNA is replicated.

The yeast in the diagram below is reproducing.

What form of reproduction is the yeast using?

A. budding

B. fission

C. sexual reproduction

D. fragmentation

1. B

2. C

3. D

4. A

5. A

6. C

7. B

8. C

9. B

10. A

11. --

12. C

13. B

14. A

15. C

16. C

17. D

18. D

19. A

20. C

21. B

22. B

23. A

24. C

25. --

26. B

27. B

28. A

29. D

30. C

31. A

32. B

33. B

36. C

37. B

38. D

39. C

40. A

INSTRUCTIONS: Use the words in the box below to fill in the blanks based on what you have learned about cellular differentiation. Words may be used more than once or not used at all.

Word Bank

anaphase binary fission cytokinesis G1 G2 interphase metaphase mitosis prophase replicate synthesis telophase

CLOZE 1 ______is the process of cell division or growing more cells. Before a cell can divide, it must ______its DNA. Prior to replicating the DNA, the chromosomes grow and prepare themselves for DNA replication in the

______phase. The chromosomes replicate themselves in the S or

______phase of the cell cycle. After the S phase, the cell goes through the

______phase where it prepares itself for mitosis. The G1, S, and G2 stages are collectively called ______. The first stage of mitosis involves the condensing of chromosomes and the disappearance of the nuclear envelope; this stage is known as

______. In the ______stage, the sister chromatids align on an equatorial plate. The sister chromatids separate and each chromosome moves to an opposite pole during ______. During ______, the chromatin expands, the nuclear envelope reappears, and the two nuclei appear in the cell. During

______, the cytoplasm divides, and the cell splits into two cells. Mitosis occurs in eukaryotic cells; a similar process called ______occurs in prokaryotic cells.

1 Cellular Differentiation

INSTRUCTIONS: Use the words in the box below to fill in the blanks based on what you have learned about cellular differentiation. Words may be used more than once or not used at all.

Word Bank blood bone epithelium hormone leaf muscle one root stem three

CLOZE 2 Eukaryotes have specialized cells that have only ______function. A plant’s

______cell is used to absorb minerals and water from the soil. The

______cell provides structural support for a plant so that the plant can hold itself up toward the sky. The ______cell contains chloroplasts and conducts photosynthesis. Animals also have specialized cells. ______cells transport gases and nutrients through the body. ______cells produce movement. ______cells such as those found on the outer layer of the skin and organs are used to secrete and absorb materials.

2 Cellular Differentiation

INSTRUCTIONS: Use the words in the box below to fill in the blanks based on what you have learned about cellular differentiation. Words may be used more than once or not used at all.

Word Bank

binary fission inactive RNA genetic cell differentiation cell replication environmental deactivated DNA activated CLOZE 3 Specialized cells were not always specialized; they began their life in a zygote. The process,

______, changed the cell from being less to more specialized.

The changes can be caused by naturally-occurring substances in the body, such as proteins or

DNA, or they can be caused by ______factors, such as chemicals or high temperatures. Results of cell differentiation normally lead to more specialized cells that have a specific function in the organism. All cells contain the same ______, but not every cell will express it the same way. Some cells can be turned on or ______only when their genes are needed to make a certain protein. The rest of the time, the cells are turned off or are ______.

3 Cell Differentiation

Frogs and You

1 Since the 1990s, there has been a sharp increase in the number of frogs found with deformities in the United States. Frogs have been found with three heads or extra sets of legs. Frogs have even been found with smaller frogs growing out of their backs! What could be causing this epidemic of deformities, and why are frogs so susceptible?

2 Frogs are amphibious. Even though many amphibians spend their adult life on land, most spend a significant portion of their life cycle in water. Amphibians go through amazing transformations from egg to tadpole to adult. At each stage, complicated cellular differentiation cycles must occur. Cells must receive messages that trigger specific responses. Specific parts of a cell determine whether that cell will start to divide to form tissues which will become a leg, an arm, or a head. Environmental factors can disrupt the signaling processes. Cells may instead be directed to create four legs, two heads, or perhaps to keep the tadpole tail. So, what could be happening in the water to "confuse" these cellular mechanisms?

2 Some scientists have hypothesized that pesticides are to blame for frog deformities. Other scientists claim that parasites are the ones causing the problem. Interestingly, it turns out that the interaction between pesticides and parasites may be what is to blame for the dramatic increase in deformities. In 2002, a study was published in the Proceedings of the National Academy of Sciences. It examined tadpoles infected with trematode parasites. They developed more frequent and serious deformities when exposed to pesticides in the water run-off from farms, parks, and homes than those that were not exposed to pesticides (Danielson, 2002).

2 Trematodes are the same parasites that can cause "swimmer's itch" in people. The trematode's normal host is a pond snail, but the larvae can infect other animals in the pond, such as frogs. The larvae form cysts that can disrupt cell differentiation in the growing tadpoles. The other problem is pesticides. The most common pesticides used in the U.S. are the weed-killer Atrazine and insecticides Malathion and Esfenvalerate (Danielson, 2002). Users must follow manufacturers' instructions when these pesticides are applied to fields, homes, and parks. Otherwise, these chemicals can sometimes make their way into streams, ponds, and wetlands – homes to most amphibians.

1 Cell Differentiation

5 Extensive research has been done on amphibians and pesticides. According to studies by the manufacturer of Atrazine, presence of the weed-killer alone does not cause deformity in developing frogs (Kloas, et al, 2009). The EPA also says that, though Malathion breaks down quickly, it is toxic to fish and beneficial insects (EPA, 2008). The testing done with Esfenvalerate shows few harmful effects on mammals. However, the testing does show toxic effects on birds, fish, and daphnia that live in the water.

6 But, what is the link between the trematode larvae, pesticides, and frog deformities? Think of all of the developmental steps that a frog must go through from egg to adult. It is easy to see how minor disruptions in their aquatic environment could cause major deformities. Signaling triggers may be turned off, or may go into overdrive.

7 The researchers found that the pesticides in the water had reduced the amount of white blood cells found in tadpoles compared with other tadpoles that did not have exposure to pesticides. White blood cell count is a measure of an animal's immunity. Lower levels of white blood cells mean lower immunity. These white blood cells would normally detect and destroy an invasive trematode larva. But, the pesticides reduced the numbers of white blood cells, reducing the tadpole's immunity. This made it easier for trematode larvae to invade the tadpoles. Therefore, more disruptions were caused in the process of cell differentiation, leading ultimately to more frog deformities.

2 Cell Differentiation

1 Why is frog development susceptible to minor environmental changes?

A They live a significant portion of their life in water.

B They go through many developmental changes.

C They are not adapted to live in aquatic environments.

D Both A and B

2 What are the main factors or causes in the disruption of the frog's cellular processes?

A The disruptions are unexplained.

B Larval cysts disrupt the developmental cycle and pesticides lower white blood cell count.

C Water density and temperature extremes.

D Radiation and global warming.

3 Cell Differentiation

3 The pesticide manufacturers have research which shows that their products do not cause deformities in frogs. Studies by independent researchers show a link between pesticides and frog deformities. How can these two results both be true?

A Manufacturer's tests were done in the absence of parasites.

B Different types of frogs were studied and had different responses to the chemicals.

C They cannot both be true. The independent researchers have made a mistake interpreting their results.

D They cannot both be true. The manufacturers are trying to fool the public into buying their pesticides.

4 Why should consumers read and follow directions on pesticide labels?

A To protect their own health

B To protect the health of amphibians like frogs

C To prevent pesticides from being washed into nearby streams and other waterways

D All of the above

4 Cell Differentiation

5 How did tadpole white blood cell counts affect the number of deformities in the frogs?

A The less white blood cells the frogs had, the more deformities the frogs had.

B The less white blood cells the frogs had, the less deformities the frogs had.

C The number of white blood cells would fluctuate, and deformities would result during these periods.

D White blood cell counts had nothing to do with frog deformities.

6 What impact does knowing what causes the deformities in the frogs have on the environment?

A Provides justification to eliminate trematode parasites from our bodies of water

B Provides evidence that we should not use pesticides since they are damaging the frogs

C Demonstrates that environmental systems are complex and interconnected, so we must seek complex solutions

D Does not make any difference

5 BIO 3A Meiosis

Meiosis is a form of cell division in which unique gametes are produced. Gametes are sex cells—egg and sperm—that contain only half of the genetic material of the parent cell. Meiosis vs. Mitosis

Mitosis is directly involved in the division of a cell's nucleus during the cell cycle. Meiosis, on the other hand, is not directly involved in the cell cycle. Meiosis is a process in which a cell undergoes two successive nuclear divisions.

Organisms are able to grow and new cells are produced as a result of mitosis. Through mitosis, existing cells create identical replicas of themselves. Mitosis is performed in cells so that organisms can grow, old cells can be replaced, and so that some organisms can use asexual reproduction to produce offspring.

Meiosis is a two-step process of cell division that produces four cells that contain half of the number of chromosomes present in the parent cell. Meiosis only occurs in multicellular organisms and is necessary for sexual reproduction.

Step by Step

The major events that occur during meiotic cell division are described below.

Interphase

Chromosomes are copied during interphase prior to the start of meiosis. This short period of interphase is known as the S phase (for synthesis).

Meiosis Begins

Prophase I

During prophase I, homologous chromosomes pair and become tetrads (two chromosomes or four chromatids). Crossing over between homologous chromosomes occurs at this stage.

Metaphase I

After crossing over occurs, homologous chromosomes line-up along the equator.

Anaphase I

Whole chromosomes separate from the tetrad formation and move to opposite sides of the cell. Each chromosome still has two sister chromatids.

Telophase I

During telophase I, a nuclear membrane forms around each set of chromosomes. Each cell now has one set of chromosomes and is haploid (n).

Prophase II

Sister chromatids become short and thick at the beginning of prophase II.

Metaphase II

The chromosomes migrate to the center of the nucleus and line-up along the equator by the end of metaphase II.

Anaphase II

During anaphase II, sister chromatids are pulled apart by microtubules to opposite poles.

Telophase II

A nuclear envelope forms around each set of chromosomes and meiosis II is complete.

Meiosis Ends

Cytokinesis

After meiosis, cytokinesis takes place. During cytokinesis, the cytoplasm and organelles are divided among the four haploid daughter cells. Meiosis and Sexual Reproduction

Sexually-reproducing organisms usually contain two sets of chromosomes in their somatic cells—one set from each parent. A pair of similar chromosomes with the same genes in the same locations is known as a homologous pair, and cells that contain homologous pairs are called diploid. This means that every diploid human cell contains 22 homologous pairs of autosomal (non-sex) chromosomes and 1 pair of sex chromosomes. During meiosis, haploid cells are produced. These resulting haploid cells are called gametes. Female gametes are called eggs, and male gametes are called sperm. Sperm cells and egg cells are both haploid because they only contain half of the genetic information of normal cells.

In the above diagram, a male cell is shown on the left, and a female cell is shown on the right. Through the process of meiosis, sperm cells are formed from the male cell, and egg cells are formed from the female cell. In the final step of the diagram, a haploid sperm cell combines with a haploid egg cell to form a diploid offspring cell. Sexual reproduction is used by most complex organisms, such as humans. During fertilization, the chromosomes from the egg cell combine with the chromosomes from the sperm cell. Since it receives half of its genes from each parent, the offspring is not identical to either parent. In this way, sexual reproduction produces more genetic diversity throughout a species than does asexual reproduction.

Following fertilization, normal mitotic cell division ensues. Chromosomal Crossing Over

Sexual reproduction also introduces genetic diversity because of chromosomal crossing over during meiosis. Each allele that codes for a specific trait is located on a separate chromosome. These chromosomes, known as homologous chromosomes, are similar in shape and size, and the genes that code for particular traits are in the same locations.

During prophase I of meiosis, homologous chromosomes pair up and come into close proximity with one another. While located close together, genes can sometimes be exchanged as the chromosomes cross over one another.

During crossing over, parts of chromosomes may break off and reattach, so one version of a trait may be exchanged for a different version of the same trait (e.g., a blue-eyed gene may be exchanged with a brown- eyed gene).

Because pieces of chromosomes physically relocate, crossing-over can produce allelic combinations in offspring that were not present in either parent, thus increasing genetic diversity in a population. Nondisjunction

Errors that occur during the process of meiosis can cause chromosomal mutations, which affect groups of genes or entire chromosomes. Nondisjunction is one type of chromosomal mutation. Nondisjunction occurs when chromosomes do not separate correctly during cell division. The resulting daughter cells will either be missing chromosomes or have extra copies of chromosomes, conditions called aneuploidy. Nondisjunction can occur if homologous chromosomes fail to separate during meiosis I, or if sister chromatids fail to separate in meiosis II or during mitosis.

The images below compare normal cell division to cell division in which nondisjunction has occurred.

Notice the abnormal number of chromosomes in the daughter cells on the right. One daughter cell has 2 copies of the chromosome whereas the second cell is missing a copy.

Nondisjunction can result in cells that have one chromosome missing, a condition called monosomy, or one extra chromosome, a condition called trisomy. Most monosomies are lethal during development.

Some chromosomal mutations occur in autosomal (non-sex) chromosomes. • Trisomy 21, or Down syndrome, is an example of an abnormality that occurs when an extra copy of chromosome 21 is passed on to an offspring. People with Down syndrome typically have distinct physical characteristics, such as an enlarged tongue, and they may have intellectual disabilities and speech impairments.

Some chromosomal mutations occur in the sex chromosomes. • Klinefelter's syndrome, for example, is an abnormality in which a male has two X chromosomes (XXY). Males with Klinefelter's syndrome may be infertile, or have reduced fertility, and they may be at greater risk for other diseases, such as male breast cancer and osteoporosis. • Trisomy X is an abnormality in which a female has three X chromosomes (XXX). Females with trisomy X often have learning disabilities and may be taller than normal, but they can usually undergo normal sexual development and conceive children. • Turner syndrome is an abnormality in which a female only receives one complete X chromosome. Women with Turner syndrome may be infertile and/or have other health problems. Turner syndrome is the only monosomy known to be survivable in humans.

All of the above abnormalities are examples of genetic diseases caused by nondisjunction.

Karyotypes

A karyotype is a complete set of chromosomes that constitutes the entire genome of an organism. Normal Karyotypes

Humans normally have forty-six chromosomes. Forty-four are autosomal chromosomes and two are sex chromosomes. These forty-six chromosomes make up the normal human karyotype. A normal human female karyotype contains 22 pairs of autosomal chromosomes and one pair of sex chromosomes (XX). A normal human male karyotype contains 22 pairs of autosomal chromosomes and one pair of sex chromosomes (XY).

The normal human karyotype contains forty-six chromosomes.

Image courtesy of the U.S. National Library of Medicine

The differences in sex chromosomes of mammals are relatively easy to identify. Y-chromosomes are always significantly smaller than X-chromosomes because Y-chromosomes carry much less genetic information. In fact, Y-chromosomes only contain traits that code for male sexual characteristics while X-chromosomes carry information that all individuals need to survive. Abnormal Karyotypes

Abnormal karyotypes can result in developmental abnormalities. For example, in humans, Down syndrome is caused by an extra copy (or trisomy) of chromosome 21, resulting in three copies of this chromosome being present. Since there is an extra copy of chromosome 21, there are forty-five autosomal chromosomes and two sex chromosomes present.

This karyotype is from a human male with Down syndrome. Notice that it contains an extra copy of C21, resulting in a total of forty-seven chromosomes.

Image courtesy of the Human Genome Project

The disease Cri du chat, which causes children to have a cat-like cry, is caused by the deletion of part of chromosome 5. Down syndrome and cri du chat are both caused by an individual's abnormal karyotype. Some chromosomal abnormalities occur in the sex chromosomes. Trisomy X, for example, is a type of chromosomal abnormality in which a female has three X chromosomes (XXX). Individuals with trisomy X usually undergo normal development. Sometimes, however, women with trisomy X have learning disabilities and may be taller than normal, but they do typically undergo normal sexual development and are able to conceive children. Turner syndrome, on the other hand, is caused by a female only receiving one complete X chromosome and can result in infertility and other health problems.

While some diseases caused by mutations have only minor effects, many can cause serious problems. Examining an individual's karyotype can help lead to the diagnosis of genetic diseases such as the ones discussed above.

BIO 3A Meiosis 1 Question 1 .

During sexual reproduction, gametes, or sex cells, are produced through the process of meiosis.

How many chromosomes should be in each cell labeled with an X?

A. 16

B. 4

C. 8

D. 32

The diagram below shows the process of meiosis.

Which of the following best describes how the process of meiosis helps preserve genetic continuity from one generation to the next?

A. Although daughter cells produced during meiosis contain more genetic information than their parent cell, all the genetic information they contain was duplicated from the parent cell.

B. Although daughter cells produced during meiosis contain less genetic information than their parent cell, all the genetic information they contain came from the parent cell.

C. Daughter cells produced during meiosis contain more genetic information than their parent cell, and not all of the genetic information present came from the parent cell.

D. Daughter cells produced during meiosis contain less genetic information than their parent cell, but not all of this genetic information came from the parent cell.

Question 3 .

What is the main function of meiosis?

A. to produce a clone of an organism in asexual reproduction

B. to produce more embryonic cells following fertilization

C. to produce more body cells within an organism

D. to produce gametes for sexual reproduction

Animal # of Chromosomes in Body Cells Ferret 40 Giraffe 62 Gorilla 48 African hedgehog 90 Kangaroo 12 Spotted skunk 64

A ferret sex cell divides by meiosis. The daughter cells produced each have ______chromosomes.

A. 20

B. 40

C. 10

D. 60

Question 5 .

During meiosis, homologous chromosomes frequently exchange portions of their DNA. This process increases the number of different genotypes that an offspring can inherit. What is the name of this process?

A. genetic transfer

B. transduction

C. crossing-over

D. mutation

Question 6 .

Which of the following is a process during meiosis that leads to genetic variation?

A. DNA organizes into chromosomes within the nucleus

B. cellular material replicates before separation

C. genes independently separate from one another

D. the nuclear envelope breaks down within the cell

An animal was injured while hunting for prey. The animal's body needs to produce more cells to heal the injury. How will this happen?

A. New cells are produced through mitosis, where each chromosome was copied exactly, so the cells produced are identical to each other.

B. New cells are produced through mitosis, where only half of the chromosomes were copied, so the cells are different from each other.

C. New cells are produced through meiosis, where only half of the chromosomes were copied, so the cells are different from each other.

D. New cells are produced through meiosis, where each chromosome was copied exactly, so the cells produced are identical to each other.

Question 8 .

______is a source of genetic variation that involves the swapping of sections of chromosomes during meiosis.

A. Translation

B. Crossing over

C. Fertilization

D. Transcription

Question 9 .

Humans possess two alleles, or variations, for each gene. The alleles may be the same, or they may be different.

When humans reproduce, their alleles are separated and independently sorted into different gametes, or sex cells. So, when sex cells randomly combine during fertilization to produce offspring, there is

A. a high probability of producing a clone.

B. an increase in genetic variation.

C. a decreased risk of mutation.

D. a low probability of survival.

Genes can sometimes be exchanged between homologous chromosome pairs. This process is known as crossing-over.

Which of the following statements is true of crossing-over?

A. Crossing-over contributes to genetic diversity or variation.

B. Crossing-over always results in a non-beneficial mutation.

C. The gene for eye color can be exchanged with the gene for hair color during crossing- over.

D. Only one gene may be exchanged at a time during crossing-over.

Question 11 .

Meiosis is the process of cell division that produces gametes. Gametes in humans typically contain 23 chromosomes each. In some cases, homologous chromosomes fail to separate, resulting in gametes with a different number of chromosomes. Which of the following best describes the process in which homologous chromosomes fail to separate?

A. independent assortment

B. nondisjunction

C. crossing over

D. gene mutation

Question 12 .

Directions: Select each correct answer. More than one answer may be correct.

During meiosis, genetic diversity results from which of the following processes?

independent assortment of chromosomes

replication of the cell's DNA

recombination via crossing over

What is occurring in the diagram below?

A. Alleles are independently assorting.

B. Sister chromatids are separating.

C. Segments of DNA are crossing over.

D. Genes are replicating.

Question 14 .

Which of the following is displayed in the above diagram?

A. the transfer of genetic information from parents to offspring through sexual reproduction and the processes of meiosis and fertilization

B. the transfer of genetic information from parents to offspring through asexual reproduction and the processes of mitosis and binary fission

C. the formation of diploid gametes through asexual reproduction and the processes of spermatogenesis and oogenesis

D. the formation of haploid spores through sexual reproduction and the processes of sporogenesis and alternation of generations

Through the process of meiosis, sex cells are produced that are

A. unique with a diploid set of genetic information.

B. unique with a haploid set of genetic information.

C. identical with a diploid set of genetic information.

D. identical with a haploid set of genetic information.

Question 16 .

Meiosis I is often referred to as reduction division because it results in the reduction of the chromosome number from diploid to haploid. The chromosomes that remain in each cell are made of sister chromatids. During meiosis II, what will happen to the sister chromatids?

A. They will duplicate and then separate.

B. They will stay together to form new cells.

C. They will exchange segments of DNA.

D. They will separate into different cells.

Question 17 .

Which of the following is true of the daughter cells produced during asexual reproduction?

A. The genetic information in parent cells is removed completely and given to daughter cells.

B. The genetic information in parent cells is copied exactly and passed to daughter cells.

C. The genetic information in parent cells is altered significantly and passed to daughter cells.

D. The genetic information in parent cells is completely different from that of the daughter cells.

Which of the following statements is true of the process shown below?

A. The cells formed at the end of the process contain the same number of chromosomes as the original cells.

B. The cells formed at the end of the process only have half of the chromosomes as the original cells.

C. The cells formed at the end of the process do not contain any of the genetic material from the original cells.

D. The cells formed at the end of the process are identical to the original cells.

Question 19 .

The diagram below depicts a cellular process.

The process shown above occurs during

A. diffusion.

B. asexual reproduction.

C. active transport.

D. sexual reproduction.

During normal meiosis, homologous chromosomes pair up and separate so that each gamete receives a copy of every chromosome.

Sometimes an error is made during this separation and homologous chromosomes fail to separate. This results in one gamete that has two copies of the chromosome, and another gamete that does not have the chromosome at all.

This type of error is known as ______and usually results in zygotes that either do not develop to term or have severe abnormalities.

A. chromosome translocation

B. chromosome insertion

C. chromosome inversion

D. chromosome nondisjunction

1. A

2. B

3. D

4. A

5. C

6. C

7. A

8. B

9. B

10. A

11. B

12. --

13. C

14. A

15. B

16. D

17. B

18. B

19. D

20. D

Triple X syndrome, or trisomy X, occurs when a female has an extra X chromosome in each of her cells. This results when the mother's reproductive cells divide improperly, and two X chromosome are moved into one gamete. When that gamete is fertilized and the father's DNA and X chromosome are combined with the mother's, that gives the cell three X chromosomes instead of two.

Triple X syndrome occurs because of ______.

A. point mutations

B. deletions

C. nondisjunction

D. crossing over

Question 2 .

What is the name of the process that appears in the diagram below?

A. meiosis

B. mitosis

C. differentiation

D. fertilization

A karyotype is an image of an organism's genes. An example is shown below.

By grouping images of a fetus' homologous pairs together and arranging them by shape and size, scientists can easily see whether the baby has

A. a thyroid disorder.

B. Down's syndrome, which results from having the wrong number of chromosomes.

C. a specific allele that codes for blue eyes.

D. an increased chance of developing skin cancer later in life.

Question 4 .

Which of the following correctly describes how the daughter cells produced during mitosis and meiosis compare to their parent cell?

A. Meiosis produces four cells with half the number of chromosomes as the parent cell, whereas mitosis produces two cells with the same number of chromosomes as the parent cell.

B. Meiosis produces two cells with half the number of chromosomes as the parent cell, whereas mitosis produces four cells with the same number of chromosomes as the parent cell.

C. Meiosis produces four cells with twice the number of chromosomes as the parent cell, whereas mitosis produces two cells with half the number of chromosomes as the parent cell.

D. Meiosis produces two cells with twice the number of chromosomes as the parent cell, whereas mitosis produces four cells with half the number of chromosomes as the parent cell.

Klinefelter syndrome is a chromosomal condition that affects males. This syndrome can cause hormonal and physical symptoms. The image below models the karyotype of an individual diagnosed with Klinefelter syndrome.

What claim about the cause of Klinefelter syndrome is best supported by the karyotype?

A. An error in mitosis that results in too many sex chromosomes causes Klinefelter syndrome.

B. An error in meiosis that results in a missing Y chromosome causes Klinefelter syndrome.

C. An error in mitosis that results in absent sex chromosomes causes Klinefelter syndrome.

D. An error in meiosis that results in an additional X chromosome causes Klinefelter syndrome.

Types of Chromosome Disorders

Disease Characteristics Cause Cri-du-chat deletion of parts of chromosome 5 Syndrome improperly developed larynx (Cry of the babies cry like distressed cats Cat) severe mental retardation small round faces small cranium

Edward's extra chromosome 18 Syndrome severe mental retardation (Trisomy 18) elongated skull very narrow pelvis feet with round bottoms two central fingers grasped by thumb and little finger death in early infancy

extra chromosome 21 mild to severe retardation short height Down broad hands Syndome stubby fingers and toes (Trisomy 21) round face large protruding tongue speech difficulties

Down extra chromosome 21 attached to Syndrome same as Trisomy 21 chromosome 14 (14-21 Translocation) Turner's lack of a second sex chromosome Syndrome female appearance (XO) infertility

Klinefelter's extra X chromosome Syndrome female characteristics (XXY) infertility

The table above describes different types of chromosome disorders. Which diseases are caused by an extra chromosome?

A. Down Syndrome, Turner's Syndrome, Klinefelter's Syndrome

B. Edward's Syndrome, Down Syndrome, Klinefelter's Syndrome

C. Cri-du-chat Syndrome, Turner's Syndrome, Klinefelter's Syndrome

D. Edward's Syndrome, Cri-du-chat Syndrome, Turner's Syndrome

By the end of mitosis, ______cells are produced, whereas by the end of meiosis, ______cells are produced.

A. two; four

B. four; two

C. three; one

D. one; three

Question 8 .

The zygote divides and produces more cells through the process of ______.

A. meiosis

B. mitosis

C. implantation

D. specialization

Question 9 .

Daughter cells produced when cells undergo mitosis are genetically ______, and daughter cells produced when cells undergo meiosis are genetically ______.

A. flawed, perfect

B. diverse, identical

C. identical, diverse

D. perfect, flawed

An animal was injured while hunting for prey. The animal's body needs to produce more cells to heal the injury. How will this happen?

A. New cells are produced through meiosis, where only half of the chromosomes were copied, so the cells are different from each other.

B. New cells are produced through mitosis, where each chromosome was copied exactly, so the cells produced are identical to each other.

C. New cells are produced through meiosis, where each chromosome was copied exactly, so the cells produced are identical to each other.

D. New cells are produced through mitosis, where only half of the chromosomes were copied, so the cells are different from each other.

Question 11 .

How are the processes of mitosis and meiosis similar to each other?

A. Both processes begin with similar events, including chromosome replication.

B. Both processes end with the same number of chromosomes present in each cell.

C. Both processes involve only one division of cellular materials.

D. Both processes result in the same number of cells produced.

Question 12 .

When a body cell divides through the process of mitosis, the chromosomes in the daughter cells

A. represent only the healthiest chromosomes from the parent cell.

B. are formed when chromosomes from the parent cell cross over.

C. represent only half of the chromosomes in the parent cell.

D. are identical to the chromosomes of the parent cell.

Types of Chromosome Disorders

extra chromosome 21 mild to severe retardation short height Down broad hands Syndome stubby fingers and toes (Trisomy 21) round face large protruding tongue speech difficulties

Down extra chromosome 21 attached to Syndrome same as Trisomy 21 chromosome 14 (14-21 Translocation) Turner's lack of a second sex chromosome Syndrome female appearance (XO) infertility

Klinefelter's extra X chromosome Syndrome female characteristics (XXY) infertility

A cat's coloring is mostly determined by genes on their X chromosomes, which contain alleles for colors, such as black, orange, gray, and cream. The allele for white fur is located on a different gene.

Calico cats, by definition, must display three different colors in their fur - white plus two of the other colors. This is easily possible in female cats, because females normally possess two X chromosomes. However, this occurs rarely in male cats, because males typically possess only one X chromosome plus one Y chromosome.

What must be the genetic make-up of a male calico cat, and what type of chromosome disorder does this most resemble?

A. XX, Down's syndrome

B. XYY, Cri-du-chat syndrome

Question 14 .

Most plants and animals in the world reproduce by sexual reproduction. Which process is responsible for the genetic variation found in organisms that reproduce this way?

A. synthesis

B. cytokinesis

C. meiosis

D. mitosis

Question 15 .

What is the main function of meiosis?

A. to produce more body cells within an organism

B. to produce a clone of an organism in asexual reproduction

C. to produce gametes for sexual reproduction

D. to produce more embryonic cells following fertilization

Question 16 .

Mitosis and meiosis are methods of cell division.

Which of the following is true of these two methods?

A. Meiosis involves only one division, while mitosis involves two divisions.

B. Mitosis involves two or more divisions, while meiosis involves exactly two divisions.

C. Mitosis involves only one division, while meiosis involves two divisions.

D. Meiosis involves two or more divisions, while mitosis involves exactly two divisions.

Turner syndrome is a chromosomal condition that only affects females. This syndrome causes physical and hormonal symptoms. The image below models the karyotype of an individual with Turner syndrome.

Which of the following claims about the cause of Turner syndrome is best supported by the karyotype?

A. Turner syndrome is the result of an error in mitosis, since affected individuals have a single missing sex chromosome.

B. Turner syndrome is the result of an error in mitosis, since affected individuals have half as many nonsex chromosomes as unaffected individuals.

C. Turner syndrome is the result of an error in meiosis, since affected individuals have a single missing sex chromosome.

D. Turner syndrome is the result of an error in meiosis, since affected individuals have half as many nonsex chromosomes as unaffected individuals.

Question 18 .

Mitosis and meiosis are processes vital to the survival and reproduction of an organism. What process takes place in meiosis but not mitosis?

A. DNA replication

B. crossing over

C. sister chromatids separating

D. DNA condensing into chromosomes

1. C

2. B

3. B

4. A

5. D

6. B

7. A

8. B

9. C

10. B

11. A

12. D

13. D

14. C

15. C

16. C

17. C

18. B

Part I: Word Scramble

Directions: Use the clues to help you unscramble each word or phrase. Write the unscrambled word or phrase in the space provided. 1. SIOCRSNG VROE ______Exchanging segments of genes between homologous chromosomes that results in new combinations of genes

2. ASXULE ORENROTIUCPD ______The process in which two parents contribute genetic information to form an offspring

3. EOMHMROCOSS ______A strand of DNA wrapped around proteins; carries genetic information

4. LAPOHID ______Having only one set of each chromosome

5. IESIOSM ______The process in which haploid cells are formed from a parent cell

6. MATEEG ______The sex cells such as the sperm and egg

7. CGEENTI IRVTIAONA ______The diversity in gene frequency in a population

8. ENGE ______Unit of heredity

1 Meiosis

Attachment: Student Worksheet

1. Why is it important that the daughter cells are genetically different after meiosis? ______Crossing over enables the daughter cells to be genetically different from each other, which ______leads to greater variety in our species. ______

2. Why is it important that the DNA is replicated during Interphase? ______If______the DNA did not replicate during interphase, there would be the incorrect number of chromosomes______in each cell after mitosis and meiosis. ______

3. If a liver cell contains 46 chromosomes, how many chromosomes will the following cells contain? a. Sperm _____23 b. Heart _____46 c. Zygote _____46 23 d. Egg _____

4. What does the picture below represent? Label the 3 individual cells and specify if they are haploid or diploid. ______Fertilization Egg Zygote Haploid Sperm Haploid Diploid n 2n n + →

5. Does meiosis increase or decrease biodiversity? Explain. ______Meiosis increases biodiversity because the chromosomes randomly sort and also go ______through crossing over. ______

1 912.L 16.16 Meiosis

✓ Key Student Handout

Using all of the following terms in the word bank, complete the graphic organizer.

2 cell divisions 4 daughter cells Egg cells

Half the # of chromosomes Genetic diversity Crossing over

Sperm cells Gametes Haploid

Correct # of chromosomes To in zygote ensure Half the # of the chromosomes

with Haploid 4 2 cell daughter that divisions cells are has Genetically

produces different

Meiosis because of

increases Takes place in Gametes Crossing Genetic Which because over are diversity of

Sperm Egg cells cells

2 Meiosis

Student Handout

1. Why is it important that the daughter cells are genetically different after meiosis? ______

2. Why is it important that the DNA is replicated during Interphase? ______

3. If a liver cell contains 46 chromosomes, how many chromosomes will the following cells contain? a. Sperm _____ b. Heart _____ c. Zygote _____ d. Egg _____

4. What does the picture below represent? Label the 3 individual cells and specify if they are haploid or diploid. ______

n 2n n + →

5. Does meiosis increase or decrease biodiversity? Explain. ______

1 Meiosis

Student Handout

Using all of the following terms in the word bank, complete the graphic organizer.

2 cell divisions 4 daughter cells Egg cells

Half the # of chromosomes Genetic diversity Crossing over

Sperm cells Gametes Haploid

Correct # of chromosomes To in zygote ensure the

with

that are

has Genetically

produces different

Meiosis because of

increases Takes place in

Which because

are of

2 Compare and Contrast Mitosis and Meiosis

Part I: Crossword

Directions: Use the clues to fill in the crossword puzzle with the correct words.

ACROSS:

1. A type of reproduction that produces offspring identical to the parent 2. An alteration in the DNA sequence 3. A strand of DNA wrapped around proteins; carries genetic information

DOWN:

1. Cell division that results in diploid cells identical to the parent cell 2. Cell division that results in haploid cells 3. Having only one set of each chromosome 4. Having two sets of each chromosome 5. A type of reproduction that involves the fusion of gametes 6. Diversity

1 BIO 3 B 2&3 Mendel's Laws of Genetics

Gregor Mendel's studies with pea plants formed the basis of three laws governing inheritance. Mendel's Experiments

During the 1800s, Gregor Mendel studied genetic traits in pea plants. He selected seven different traits to study, including plant height, pea pod color, and flower color. Each of the traits that Mendel studied had two possible alleles, such as tall or dwarf for height and purple or white for flower color.

The seven traits of pea plants studied by Gregor Mendel during his genetic experiments.

Mendel began his experiments by obtaining pure lines of pea plants. These pure lines were groups that produced offspring with the same traits. For example, Mendel's pure line plants with purple flowers produced offspring that all had purple flowers. Mendel knew his lines were pure because each generation kept passing on the same traits to its offspring, but he did not yet know how these traits were passed. He would later understand that these pure lines were homozygous for several traits.

Test Cross

After obtaining the pure lines, Mendel crossed a pure line that had purple flowers with a pure line that had white flowers. He called this the P generation for parent generation. Once the pollinated flowers produced

seeds, Mendel planted them. The cross of purple and white flowers resulted in F1 generation offspring that all had purple flowers (100%).

Next, Mendel crossed two of the offspring from the F1 generation. Both parents had purple flowers, but

about ¾ of the resulting F2 generation offspring had purple flowers, and about ¼ had white flowers.

Based on his data analysis, Gregor Mendel formulated three laws governing inheritance: 1. The Law of Dominance 2. The Law of Segregation 3. The Law of Independent Assortment Law of Dominance

The law of dominance states that when an organism has two or more alleles for a trait, the allele that is expressed over the other alleles is considered dominant. The other alleles are considered recessive.

In Mendel's pea experiments discussed above, the allele for white flowers was recessive to the allele for violet flowers because the allele for violet flowers masks the allele that codes for white flowers. Example 1:

A man and his wife have four children, all with freckles. The man does not have any freckles, but the wife does have freckles.

Why do all of the children have freckles?

All of the children have freckles because they inherited a dominant allele for freckles from their mother. From the Law of Dominance, it can be assumed that if the parents have different alleles for the same trait, but all of the offspring have the same allele for that trait, the inherited allele is dominant. Law of Segregation

The law of segregation states that different alleles for the same trait separate when gametes are formed. Thus, a mother that is heterozygous for brown eyes (Bb) could pass either a dominant brown allele (B) or a recessive blue allele (b) for eye color to her offspring. Example 2:

A plant with a red flower and a plant with a white flower are crossed, resulting in all red flowers. The offspring are heterozygous for flower color.

What allele(s) for flower color can the offspring plant pass on to its own offspring?

The plant can pass on the allele for red or white flower color to its offspring. A heterozygous organism has both a dominant and a recessive allele. Since the alleles separate into different gametes, an offspring could receive a gamete with one allele or the other. Law of Independent Assortment

The law of independent assortment states that when pairs of alleles separate, they do so independently of each other. Thus, the alleles for hair color and the alleles for eye color in humans are not inherited together. Example 3:

Margie's father is heterozygous for brown hair, a dominant trait, and homozygous for blue eyes, a recessive trait. Margie's mother is homozygous for blonde hair, a recessive trait, and heterozygous for brown eyes, a dominant trait.

Is it possible for Margie to inherit brown hair and brown eyes?

Yes. Since the alleles for each trait separate into gametes independent of each other, it is possible to inherit some traits from one parent and some from the other. Margie could inherit any one of several combinations of traits from her parents (blonde hair and blue eyes, brown hair and blue eyes, or blonde hair and brown eyes). Demonstration of Mendel's Laws

If a breeding experiment only studies one trait, it is known as a monohybrid cross. If two traits are studied, it is known as a dihybrid cross. The chart below shows all of the possible variations of offspring that could be produced from a cross between two pea plants that are both heterozygous for pod form and color. Because two traits are considered, this is an example of a dihybrid cross.

Punnett Squares

A Punnett square is a chart which predicts all of the possible gene combinations from two parents for a particular trait.

Punnett squares are named for the English geneticist Reginald Punnett, who discovered some of the basic principles of genetics, including sex-linkage and sex-determination. In a Punnett square, one parent's alleles are written across the top of a grid and the other parent's alleles are written down the left side of the grid. Then, the predicted genotypes of the offspring are determined inside the grid, like a multiplication table.

In the example below, two parents that are both heterozygous (Bb) for a coat color trait are crossed.

Since black coat color (B) is dominant over brown (b), the resulting progeny will approximately be: o 3:4 (75%) black coated ▪ 1:4 (25%) homozygous dominant (BB) ▪ 1:2 (50%) heterozygous (Bb) o 1:4 (25%) homozygous recessive (bb) and brown coated. This is an example of a monohybrid cross because there is only one characteristic present (coat color). However, Punnett squares can also be used to predict the gene combinations of multiple linked traits.

During meiosis, alleles are separated and assorted independently. This results in greater variation among offspring.

BIO 3B1&2 Question 1 .

Directions: Select each correct answer.

Examine the Punnett square below, which represents a cross between a male and a female pear tree. B B B ? ? b ? ? What are the possible genetic variations of offspring in this cross?

Question 2 .

Directions: Select the correct Punnett square.

Which Punnett square shows the results of a cross between two heterozygous parents?

Question 3 .

Directions: Type your answer in the box. Use numerals, not words.

If a homozygous dominant parent and a heterozygous parent are crossed, what percentage of the offspring are expected to be homozygous recessive?

Directions: Type your answer in the box. Use numerals, not words.

If a homozygous dominant parent and a heterozygous parent are crossed, what percentage of the offspring are expected to be heterozygous?

Question 5 .

According to Mendel's Law of Segregation, meiosis involves the separation of a parent organism's alleles in order to form gametes. Since the alleles separate into different gametes, only one allele passes from each parent on to an offspring. This segregation of alleles during meiosis

A. decreases the genetic variability of the offspring.

B. increases the genetic variability of the offspring.

C. increases the chance that an offspring will receive a dominant allele.

D. decreases the chance that an offspring will receive a dominant allele.

Question 6 .

What is the importance of understanding Mendel's laws of segregation and independent assortment?

A. The probability of crossing-over can be calculated.

B. The amount of genetic variation is reduced.

C. The rate of genetic mutation decreases.

D. The inherited traits of offspring can be predicted.

Question 7 .

Gregor Mendel developed several laws of heredity over the course of his genetic research. What does the first law of heredity, the law of segregation, state about genes?

A. Dominant alleles are always more likely to be inherited.

B. Two alleles for a trait separate when gametes are formed.

C. Mutations can only occur in heterozygous organisms.

D. Alleles of different genes separate independently of one another during gamete formation.

Guinea pig coat color is determined by a single gene. The allele for black coat color is dominant to brown. In a cross between two black-haired guinea pigs, 20 offspring are born. If both parents were heterozygous, probability would predict that approximately how many of the 20 offspring would have brown hair?

A. 0

B. 15

C. 5

D. 10

Question 9 .

A cross between two squash plants that produce yellow squash results in 124 offspring: 93 produce yellow squash and 31 produce green squash. What are the likely genotypes of the plants that were crossed?

A. both YY

B. both Yy

C. both yy

D. one YY, one Yy

Question 10 .

Directions: Select the correct Punnett square.

Which Punnett square shows the results of a cross between one homozygous dominant parent and one heterozygous parent?

Gregor Mendel was an Austrian monk who lived in the 1800s. Mendel is known as the "father of modern genetics" as a result of discovering two important laws - the law of segregation and the law of independent assortment.

According to Mendel's law of segregation, different alleles are separated into different gametes, or sex cells. According to the Mendel's law of independent assortment,

A. traits are sorted so the gametes from each parent are identical to each other.

B. only one version of each trait can be separated at a time.

C. similar traits must be separated into the same gamete.

D. the separation of one trait does not influence the separation of another trait.

Question 12 .

Carla receives an allele for blue eyes from her mother, and an allele for brown eyes from her father.

If brown eye color is a dominant trait and blue eye color is a recessive trait, what can be determined about the color of Carla's eyes?

A. Carla has blue eyes.

B. Carla has green eyes.

C. Carla's eye color can not be determined.

D. Carla has brown eyes.

Question 13 .

A certain type of flower has two alleles for color (blue, purple), and two alleles for stem height (tall, short). A tall blue flower and a short purple flower are crossed, resulting in tall blue flowers, short blue flowers, tall purple flowers, and short purple flowers.

What law does this example demonstrate?

A. law of multiple alleles

B. law of genetic inheritance

C. law of independent assortment

D. law of segregation

Mendel's laws of heredity can be used to predict the results of simple genetic crosses. For example, if 2 pea plants that are heterozygous for yellow seed color (Yy) are crossed, there is a 25% chance that their offspring will express the recessive trait for green seed color (yy).

The above example shows how ______govern simple genetic recombinations.

A. the laws of thermodynamics

B. Newton's laws

C. the laws of natural selection

D. the laws of probability

Question 15 .

Directions: Type your answer in the box. Use numerals, not words.

If a homozygous dominant parent and a heterozygous parent are crossed, what percentage of the offspring are expected to be homozygous dominant?

Question 16 .

Jose is growing pea plants in his garden. He notices that some plants have green pods, while others have yellow pods. He researches the species he planted and finds that green pods are dominant to yellow pods.

According to Mendel's law (principle) of dominance, which of the following statements can be said with certainty?

I. The plants with yellow pods do not have an allele for green pods. II. None of the plants with green pods has an allele for yellow pods. III. The plants with yellow pods are displaying incomplete dominance. IV. The plants with green pods might be homozygous or heterozygous for pod color.

A. I and IV only

B. III and IV only

C. III only

D. II only

Sarah is doing an experiment on pea plants. She is studying the color of the pea plants. Sarah has noticed that many pea plants have purple flowers and many have white flowers.

Sarah crosses a homozygous white flower and a homozygous purple flower. The cross results in all purple flowers.

What is true of the color of pea plants?

A. Purple flowers and white flowers are recessive to red.

B. White flowers are dominant to purple flowers.

C. Purple flowers are dominant to white flowers.

D. White flowers and purple flowers are codominant.

Question 18 .

A student crosses two homozygous plants, one with green pods and the other with yellow pods. If yellow is dominant over green, what phenotypic results will the student find in the offspring?

A. 75% green, 25% yellow

B. 75% yellow, 25% green

C. 100% yellow

D. 100% green

Question 19 .

In pea plants, tall (T) plants are dominant over short (t) plants. If a heterozygous (Tt) pea plant is crossed with a homozygous dominant (TT) pea plant, all of the resulting pea plants should be tall (TT or Tt). Each plant will receive a dominant allele from the homozygous dominant plant, while they could receive either a dominant or recessive allele from the heterozygous plant.

The fact that each plant gets only one allele from each parent plant is detailed in the law of ______.

A. segregation

B. multiple alleles

C. genetic inheritance

D. independent assortment

A student crosses two pea plants. In this species, the allele for axial flowers is dominant to the allele for terminal flowers. One of the plants that the student uses in the cross is homozygous dominant for axial flowers. The other is heterozygous, which means that it has one allele for axial flowers and one allele for terminal flowers.

If the student examines 200 offspring pea plants from this cross, which of the following is a reasonable result?

A. 98 with axial flowers, 102 with terminal flowers

B. 200 with axial flowers, 0 with terminal flowers

C. 47 with axial flowers, 153 with terminal flowers

D. 149 with axial flowers, 51 with terminal flowers

1. --

2. --

3. --

4. --

5. B

6. D

7. B

8. C

9. B

10. --

11. D

12. D

13. C

14. D

15. --

16. A

17. C

18. C

19. A

20. B

The study of how genetic traits are inherited is called genetics. Incomplete Dominance

Some alleles produce intermediate traits. That is, if one allele is incompletely dominant over the other, then a phenotype that is intermediate between the two variations can be observed.

For example, some flowering plants have an allele for red (R) color and an allele for white (r) color. However, when the plant is a heterozygote (Rr), the plant produces pink flowers rather than red or white.

Pink flowers are a result of incomplete dominance. Whenever expressed traits show a blending of two alleles, it is usually due to incomplete dominance.

Codominance & Multiple Alleles

Codominance occurs when two alleles are equally dominant. In these circumstances, the alleles are expressed simultaneously, resulting in organisms that have some kind of mixed pattern. For example, a flowering plant with codominant color genes might exhibit white and red speckled flowers in the heterozygote. In addition, some gene loci may have multiple alleles, or more than two different alleles present in varying amounts in a given population. When there are multiple alleles, some may be dominant, others recessive, and still others may be incompletely dominant to one another. The ABO blood group is a good example of a gene locus with codominance and multiple alleles.

The alleles for A blood proteins and B blood proteins are codominant to each other. Unlike incomplete dominance, there is no blending. Someone with AB bloodtype will produce both A proteins and B proteins.

Image is courtesy of NIH and Wikipedia. Polygenic Inheritance

Sometimes a particular phenotype may be determined by more than one gene. This is referred to as polygenic inheritance, where more than one gene locus has a similar and additive effect on the same trait. Traits that are coded for by many genes tend to have large variations.

Skin color, for example, is determined by three separate gene loci in humans. Each gene locus codes for slightly different traits that have an additive effect on how light or dark skin color is. Sex Determination & Sex-linked Traits

In the cells of a sexually-reproducing organisms, a pair of similar chromosomes with the same genes in the same locations is known as a homologous pair. This means that every normal human body cell contains 22 homologous pairs of autosomal chromosomes and 1 pair of sex chromosomes.

An individual's sex is determined by its combination of sex chromosomes. Females have two X chromosomes (XX), and males have an X chromosome and a Y chromosome (XY).

Sex-linked traits are those carried on the sex chromosomes. Though the Y chromosome is also a sex chromosome, it only carries traits that produce male sexual characteristics. So, the term sex-linked generally refers to traits found on the X chromosome. Human males with an XY genotype always inherit the X chromosome from the mother and the Y chromosome from the father. Since they only receive one X chromosome, XY males inherit sex-linked traits from their mothers. Females, on the other hand, receive one X chromosome from each parent. Thus, they inherit sex-linked traits from both parents.

Recessive, sex-linked traits are more common in boys than girls. This is due to the fact boys only have one copy of the X chromosome. Girls have two copies of the X chromosome, and so they have to inherit two copies of a recessive trait in order for it to be expressed.

Some examples of recessive sex-linked disorders include: • hemophilia • colorblindness • Duchenne muscular dystrophy

Males inherit recessive, sex-linked traits from their mothers.

The daughters of affected males will all become carriers. The sons will be unaffected because they do not inherit X chromosomes from their father.

Pedigrees

A pedigree chart shows how members of a certain family are related to each other, and it shows which members of the family express a certain trait or set of traits. Pedigree Symbols

In order to properly read and analyze pedigree charts, it is first necessary to understand the symbols.

Symbol Description

unaffected female

unaffected male

affected female

affected male

female carrier

male carrier

mating couple

siblings

Reading Pedigrees

Cystic fibrosis (CF) is an autosomal recessive disease, which means only individuals that inherit two copies of the allele will have the disease. And since the gene is located on an autosome, males and females have equal chances of inheriting the disease.

The following pedigree traces the incidences of cystic fibrosis through three generations of a family.

According to the chart, both parents from the first generation are carriers for the disease. As carriers, they have a 1:4 or 25% chance of having a child with cystic fibrosis. While one daughter is not affected, two of their children are carriers of the disease, and one son has the disease.

Because both parents must be carriers of the CF gene, none of the third generation offspring have the disorder.

BIO 3B3&4 Question 1 .

The pedigree shown above is based on a family with freckles (filled circles or squares) or lacking freckles (empty circles or squares). Freckles are determined by one gene locus. Which of the following statements about freckles is most likely to be correct?

A. Freckles are a sex-linked dominant allele.

B. Freckles are an autosomal recessive allele.

C. Freckles are a sex-linked recessive allele.

D. Freckles are an autosomal dominant allele.

Question 2 .

The pedigree shown below depicts a family and their hair color.

Blond hair is represented by the filled circles, and brown hair is represented by the empty circles. From this pedigree, what can be said about blond hair color?

A. Blond hair is a sex-linked recessive allele.

B. Blond hair is a sex-linked dominant allele.

C. Blond hair is an autosomal recessive allele.

D. Blond hair is an autosomal dominant allele.

Lisa breeds snakes. She bred a solid brown male python with a tan female python whose body was covered with a black diamond pattern. Upon hatching, all of the baby pythons were brown with a faint diamond pattern.

Which of the following inheritance patterns most likely determined the color of Lisa's baby pythons?

A. autosomal dominant-recessive

B. incomplete dominance

C. sex-linked

D. codominance

Question 4 .

A pedigree chart is a diagram that shows how members of a family are related to one another. It may also show which members of a family express a certain genetic trait.

In a pedigree chart, females are represented by circles and males are represented by squares. A horizontal line between a male and a female indicates a couple with offspring, and a vertical line connects the couple to their child or children. Siblings are denoted by branches off the vertical line. Each separate generation is represented by a Roman numeral.

An example of a pedigree chart is shown below.

Which of the following is true about persons A and G?

A. Person G is the grandson of person A.

B. They are not genetically related.

C. They are females with sickle-cell disease.

D. They are males without sickle-cell disease.

Question 5 .

A female dog affected by the recessive, X-linked disorder hemophilia mates with an unaffected male. If this cross results in a single male puppy, what is the probability that the puppy will be affected by hemophilia?

A. 50%

B. 0%

C. 100%

D. 25%

Which of the following best describes a sex-linked trait?

A. a trait determined by a gene located on an individual's X or Y chromosome

B. a trait whose expression depends on whether an individual is male or female

C. a trait determined by a gene located on an individual's Y chromosome only

D. a trait determined by a gene located on an individual's X chromosome only

Question 7 .

Trey goes to a rabbit farm to look at a litter of newborn rabbits. The newborns are all different colors. They are gray, black, white, light brown, and dark brown.

What type of inheritance pattern are these rabbits likely displaying?

A. dominant-recessive

B. codominance

C. multiple alleles

D. incomplete dominance

Question 8 .

If a mother has type A blood and her son has type B blood, which of the following two blood types are both possibilities for the father?

A. AB and O

B. A and B

C. B and AB

D. O and A

Question 9 .

A recessive gene located on the X chromosome is the cause of hemophilia in affected individuals. Males are more likely to have hemophilia than females because

A. females have no copies of the X chromosome.

B. males have only one copy of the X chromosome.

C. males have two copies of the X chromosome.

D. hemophilia is associated with high testosterone levels.

Punnett squares depict the genotypes of two parents and are used to predict the inherited traits of offspring. Which of the following would be the missing predicted trait in the table below?

A. OO

B. AO

C. AA

D. OA

Question 11 .

A certain species of pea plant can either be tall or short. The allele for being tall is dominant to the allele for being short. If a heterozygous tall pea plant is crossed with a homozygous short pea plant, which of the following phenotypic ratios will most likely occur in the first generation?

A. 100% tall : 0% short

B. 25% tall : 75% short

C. 75% tall : 25% short

D. 50% tall : 50% short

A pedigree chart is a diagram that shows how members of a family are related to one another. It may also show which members of a family express a certain genetic trait.

An example of a pedigree chart is shown below.

How can a pedigree be a helpful tool for future parents?

A. A pedigree chart an eliminate the possibility of parents passing any genetic disease to their child.

B. A pedigree chart can predict all of the child's future characteristics, such as height and musical ability.

C. A pedigree chart can provide the complete DNA sequence of their future child.

D. A pedigree chart can help measure the likelihood of their child inheriting certain genetic diseases.

Question 13 .

A(n) ______is a characteristic arising from genes located on gender-determining chromosomes.

A. allele

B. genotype

C. sex-linked trait

D. autosomal trait

Cats have a gene that codes for the color of their fur.

Suppose that a certain breed of cat can have black, gray, or white fur. Black fur is dominant, white fur is recessive, and gray fur is intermediate (i.e., cats with gray fur possess one allele for black fur and one for white fur).

If a gray cat and a white cat have kittens, what phenotypes could the kittens exhibit?

A. gray or white fur

B. only gray fur

C. black, gray, or white fur

D. black or white fur

Question 15 .

Rhesus macaques are monkeys whose ABO blood group functions just like the ABO blood group seen in humans. Jennifer is trying to determine the blood types of two Rhesus macaques she cares for at the zoo. She knows that the blood type of their only offspring is O.

After asking her coworker, she finds out that the mother's blood type is A. However, her coworker cannot remember the blood type of the father.

Which of the following blood types could the father have?

I. A II. B III. AB IV. O

A. I or III only

B. II or III only

C. I, II, III, or IV

D. I, II, or IV only

A pedigree chart is a diagram that shows how members of a family are related to one another. It may also show which members of a family express a certain genetic trait.

An example of a pedigree chart is shown below.

Which two individuals are not genetically related to each other?

A. J and G

B. D and F

C. B and H

D. D and E

Question 17 .

The above pedigree shows a particular inherited trait. The first-generation father passes the trait on to all his daughters and none of his sons. His daughters pass the trait on to half of their children regardless of gender. Based on this information, which of the following statements about the expressed trait is most likely correct?

A. It is an autosomal dominant allele.

B. It is a sex-linked recessive allele.

C. It is an autosomal recessive allele.

D. It is a sex-linked dominant allele.

Directions: Select all the correct mating pairs.

Chimpanzees are primates whose ABO blood group functions just like the ABO blood group seen in humans. If a juvenile chimpanzee has type O blood, which of the following mating pairs could be the chimpanzee's parents?

Question 19 .

Which of the following is an example of incomplete dominance?

A. Crossing two short pea plants produces only short pea plants.

B. A plant with red flowers and a plant with white flowers produce a plant with pink flowers.

C. Sons are more likely than daughters to inherit colorblindness.

D. A cow with red coat and a cow with white coat produce a cow with a red and white spotted coat.

Question 20 .

Mrs. Smith has blood type A. Her father has blood type A, and her mother has blood type B. If Mr. Smith has blood type AB, what is the probability that they will have a child with blood type AB?

A. 25%

B. 50%

C. 0%

D. 100%

1. D

2. C

3. B

4. C

5. C

6. A

7. C

8. C

9. B

10. A

11. D

12. D

13. C

14. A

15. D

16. B

17. D

18. --

19. B

20. A

Part I: Secret Spelling

1. GENES 2. PUNNETT SQUARE 3. TRAIT 4. GENETICS 5. MENDEL 6. DOMINANT

Secret Word: ENIGMA

Part II: Picture Descriptions

1. This squirrel has a genetic mutation that makes it albino (white). This is a recessive trait that may impact survival due to decreased camouflage abilities.

2. Three peas display the dominant trait of smooth, and one displays the recessive trait of wrinkled. This is mostly like the result of crossing two heterozygous parents, as seen in a Punnett square where 75% would have the phenotype smooth.

3. Variation between parent and offspring are explained by genetic recombination through meiosis and any mutation that may have taken place.

1 Mendel's Law

Part I: Secret Word

Directions: Use the clues to identify the words. If you identify the words correctly, the circled letters will spell out a word.

1. Portions of DNA that code for a specific protein

______E ___

2. A tool that can be used to predict the traits of offspring

______U ______

3. A physical attribute

___ R ______

4. The study of patterns of inheritance

______N ______

5. Studied pea plants to observe how traits were inherited

______D ______

6. The allele that produces the same phenotype where it is homozygous or heterozygous

______T

Secret Word: ______

1 Mendel's Law

Part II: Picture Descriptions

Directions: Use the vocabulary words associated with each picture to describe what is happening.

1. Words: mutation, recessive, environmental factors, trait ______

2. Words: traits, genetics, Punnett square, phenotype ______

3. Words: traits, genetic, meiosis ______

2 Mendel’s Law

Student Worksheet

Answer the questions below.

1. If blue color is dominant to yellow color in morning glory plants, what is the genotype of a heterozygous blue morning glory plant?

2. Which feature allows a picture to be taken of the chromosomes so that they can be paired with their matching chromosome?

3. What allows us to map our traits through our family?

4. What is the difference between codominance and incomplete dominance?

5. Two brown mice mate, producing eleven brown offspring and three albino offspring. What are the genotypes of the parents? Provide evidence to support your answer.

6. What explains the ability of allele pairs to separate randomly, or segregate, from each other during the making of gametes (egg and sperm)?

1 Mendel’s Law

Student Worksheet

Using all of the following terms in the word bank, complete the graphic organizer.

Word Bank Multiple alleles Monohybrid cross Sex-linked traits Polygenic inheritance Phenotype Punnett square Genotype Dihybrid cross Incomplete dominance Gregor Mendel Codominance

1. 2. No dominant allele

Blood type 3. Hemophilia Non-Mendelian Genetics Genetics Hair color

4. Both alleles Father of dominant 5. 6. l

predicted using offspring 8.

9. 10. 11.

2 Mendel’s Law

Square Vocabulary

This model serves as the pieces to cut out as well as the key.

representation of traits of representation Codominance TT or tt or TT Red + White = Pink Graphic Law of Segregation alleles for a trait More than two G fertilization. Multiple Alleles from each other during

Dominant Recessive Heterozygous Allele pairs separate randomly

Tt g Incomplete dominance G representation of traits Karyotype Graphic Pedigree Picture of Dominant chromosomes

TT or tt Codominance Red + White = Pink

Both traits appear traits Both Incomplete dominance Incomplete Homozygous Profile of one’s DNA Gregor Mendel Pedigree Homozygous Father of genetics DNA fingerprinting Recessive Heterozygous Gregor Mendel

Vocabulary Square

Procedure: Print the Square Vocabulary, cut the pieces apart Each student correctly match the term to its definition or to an example of the term. When the group has used all of the pieces it will form a large square, check the answers.

Once you answer the questions on the Student Worksheets, have them place the pieces back in the correct envelopes and return them.

Mendel’s Law

Student Worksheet

Answer the questions below.

If blue color is dominant to yellow color in morning glory plants, what is the genotype of a heterozygous blue morning glory plant?

✓ Bb; students may choose to use another letter to represent “blue.” The answer must contain both the capital and lowercase of the letter.

2. Which feature allows a picture to be taken of chromosomes so that they can be paired with their matching chromosome?

✓ Karyotype

3. What allows us to map the inheritance of traits through our family?

✓ Pedigree

4. What is the difference between codominance and incomplete dominance?

✓ Codominance occurs when neither trait can dominate the other; for example, a yellow flower is fertilized by a pink flower, so the resulting flower will contain both pink and yellow colors. Incomplete dominance is when there is a blending of the phenotypes; for example, when a white flower is fertilized by a red flower, resulting in pink flowers.

5. Two brown mice mate, producing eleven brown offspring and three albino offspring. What are the genotypes of the parents? Provide evidence to support your answer.

✓ The genotype for both parents is Bb. Both parents must possess a recessive allele if they produce any offspring that are albino. However, since both parents are brown, they must also possess the dominant allele.

✓ Students may also use a Punnett square to prove their answer.

6. What explains the ability of allele pairs to separate randomly, or segregate, from each other during the making of gametes (egg and sperm)?

✓ Law of segregation

1 Mendel’s Law

Student Worksheet

Using all of the following terms in the word bank, complete the graphic organizer.

Word Bank Multiple alleles Monohybrid cross Sex-linked traits Polygenic inheritance Phenotype Punnett square Genotype Dihybrid cross Incomplete dominance Gregor Mendel Codominance

1. Incomplete dominance 2. Multiple alleles No dominant allele

Blood Hemophilia type 3. Sex-linked traits Non-Mendelian Genetics Genetics

Hair color 4. Polygenic inheritance Both alleles dominant Father of

5. Codominance 6. Gregorl Mendel

7. Phenotype

predicted using offspring 8. Punnett square

9. Genotype 10. Dihybrid cross 11. Monohybrid cross

2 BIO 3C Genetic Material

Genetic material is encoded in genes, which are segments of DNA. DNA, in turn, is organized into chromosomes, which make up an organism's genome.

This organization provides an efficient way for genes to be accessed and expressed. Organization of Genetic Material

gene → DNA molecule → chromosome → genome It is important to know how genetic material is organized. The genome of an organism refers to its complete genetic makeup and includes the organism's entire set of chromosomes. The total number of chromosomes in a normal human is 46: 23 chromosomes from the mother and 23 from the father. Chromosomes, Genes, & DNA

Genetic information is encoded in DNA. DNA is located in the chromosomes of cells. Chromosomes appear very dark (when viewed under a microscope) and are located in the cell nucleus, if the cell has one.

A gene is a section of DNA located on a chromosome.

Adapted from image courtesy of NIH.

A section of a chromosome that controls a particular trait is a gene. Genes are a kind of blueprint for an organism. They contain all the information necessary to build, repair, and keep the organism running, including how to make all the different proteins and other materials the body needs.

Transcription, Translation & Protein Synthesis

Genes are used by the cell to synthesize proteins. In order to produce a protein, genes must be transcribed and translated by the machinery of the cell. Gene Expression The use of genes to produce proteins is called gene expression. Two main processes are involved in gene expression: transcription and translation. 1. During transcription, DNA in the nucleus of a cell is copied into messenger RNA molecules. 2. The messenger RNA then moves into the cell's cytoplasm and attaches to a ribosome, where it is translated into a protein. Central Dogma of Molecular Biology

Once DNA is transcribed into messenger RNA and translated into a protein, the process cannot be reversed. That is, information cannot be transferred from the protein back to the nucleic acid. This is the central dogma of molecular biology. Transcription The sequence of nitrogenous bases in a gene provides the genetic instructions needed to construct a protein. Transcription occurs when a series of chemical signals within the cell causes the gene for a specific protein to "turn on," or become active. During transcription, a segment of DNA is transcribed, or copied, to produce a complementary strand of messenger RNA (mRNA). Transcription occurs in the nucleus of the cell. The three main processes that occur during transcription are described below. 1. Initiation — During initiation, enzymes bind to a DNA sequence and unwind the double helix to expose a strand of nucleotides. 2. Elongation — As the DNA molecule unwinds, an enzyme called RNA polymerase pairs complementary RNA nucleotides with the DNA nucleotides on one of the exposed strands. Adenine (A) on DNA pairs with uracil (U) on RNA, cytosine (C) pairs with guanine (G), and thymine (T) pairs with adenine (A). For example, if the DNA strand reads 'ACG,' the complementary RNA strand would read 'UGC.' 3. Termination — Once the gene is transcribed, the new RNA molecule breaks away and the DNA strands are wound back together.

During transcription, a DNA molecule is unwound, and an RNA strand is synthesized using an exposed DNA strand as a template.

Now that transcription is completed, the RNA molecule moves to the cytoplasm of the cell, where it will be translated into a protein. Translation Translation occurs in cell organelles called ribosomes. Ribosomes contain proteins and a type of RNA called ribosomal RNA (rRNA). It is a major component of cellular ribosomes and it can act as a catalyst in chemical reactions. During translation, an mRNA strand is used to synthesize a chain of amino acid residues called a polypeptide. When mRNA leaves the nucleus, it travels until it reaches a ribosome. Each three-base segment of the mRNA strand is called a codon. A polypeptide is formed by matching the anticodon of a transfer RNA (tRNA) molecule—each of which carries a specific amino acid—to the corresponding codon on the mRNA strand. Later, the polypeptide will fold into a functional protein. The steps of translation are shown below. 1. A ribosome attaches to the 5' end of the mRNA strand. 2. Transfer RNA (tRNA) molecules carrying amino acids approach the ribosome. 3. The tRNA molecule whose anticodon corresponds to the first codon on the mRNA strand quickly attaches at the ribosome. 4. A new tRNA molecule carrying another amino acid attaches to the next codon on the mRNA strand. 5. As amino acids are added next to each other, peptide bonds form between them. 6. The previous tRNA molecule detaches from the mRNA strand and departs from the ribosome, leaving its amino acid behind. 7. The chain of amino acid residues continues to grow until the ribosome reaches a stop codon at the 3' end of the mRNA strand. This signals that no more amino acids should be added. The result is a polypeptide.

During translation, tRNA molecules bring amino acids to the ribosome, where they are linked together by peptide bonds to form a polypeptide. Codons & the Genetic Code How exactly does a sequence of nucleotides result in a chain of amino acids? The answer lies in the genetic code (or triplet code), which determines which amino acid corresponds with each three-base codon. Because codons contain three nitrogenous bases, the genetic code could theoretically produce 64 amino acids (four possible bases in the first position multiplied by four in the second position and four in the third). However, most amino acids are coded for by more than one codon. Consequently, the genetic code can only produce 20 different amino acids. While this phenomenon may seem inefficient at first glance, such redundancies often allow cells to produce the correct protein even if a gene has been affected by a mutation. For example, suppose a mutation caused a CUU codon to change to CUC, CUA, or CUG. In all three cases, the correct amino acid, leucine, would be produced.

The genetic code is shown in the table above. To determine which amino acid corresponds to a codon, find the row matching the first RNA base, the column matching the second base, and the specific codon containing the third base.

An mRNA transcript must have distinct starting and ending points, which are indicated by a start codon (AUG, which codes for methionine) and a stop codon (UAA, UAG, or UGA). As with all nucleic acid sequences, codons are transcribed and translated in the 5'→3' direction. Gene Sequence Determines Protein Structure The final structure of a protein is determined by the sequence of its amino acid residues. In turn, the amino acid sequence is determined by the original gene sequence that was transcribed and translated. Once a chain of amino acid residues is produced, it undergoes a series of folds, bends, and twists to arrive at its final structure. There are four distinct levels of protein structure:

Primary Structure — The primary structure of a protein is simply its linear amino acid sequence (polypeptide). Each type of protein has a unique primary structure that distinguishes it from every other protein. Secondary Structure — In certain places, hydrogen bonding causes the polypeptide to twist into structures called alpha helices or fold into structures called beta sheets. Most proteins contain both of these structures. Tertiary Structure — Tertiary structure refers to the tightly compacted form of a single protein molecule. This three-dimensional structure is primarily determined by the hydrophobic (water repelling) amino acid residues in the polypeptide, which naturally face inward, while hydrophilic amino acid residues face outward. Quaternary Structure — Many proteins are actually composed of multiple subunits. When these subunits (each of which is translated separately) come together, the protein achieves quaternary structure. As shown in the diagram, the oxygen-carrying protein hemoglobin is made up of four distinct subunits.

Proteins and Life The process of protein synthesis produces the proteins that carry out the functions needed for life. These functions include breaking down food, protecting a body from bacteria and viruses, and moving muscles. This is a small list of the life functions carried out by proteins. These functions are performed by specialized cells, which synthesize the specific proteins needed to perform a function. The genes that are expressed by a specialized cell determine the proteins that the cell can synthesize. The structure of a protein determines its function. Specialized cells and the proteins that they synthesize are essential for life.

BIO 3C1&2 Question 1 .

The genetic information that is passed from a parent to its offspring is found in ______.

A. DNA molecules

B. carbon atoms

C. amino acids

D. hydrogen bonds

Question 2 .

Which of the following best describes a gene?

A. a sequence of amino acids that codes for a protein product

B. an expressed trait that makes up a DNA sequence

C. a chain of proteins that make up a DNA sequence

D. a region of DNA that codes for a protein product

Question 3 .

When a cell needs a particular protein synthesized, messenger RNA (mRNA) is produced from DNA through transcription.

How is genetic information "read" from mRNA?

A. as ribose

B. as codons

C. as uracil

D. as amino acids

The table shows the amino acids produced by different sequences in the genetic code.

According to the table, which nucleotide sequences code for the amino acid leucine (Leu)?

A. UUA and UUG only

B. CUU, CUC, CUA, CUG, UUA, and UUG only

C. CUU, CUC, CUA, and CUG only

D. AAA and AAG only

Question 5 .

Which of the following describes the role of proteins?

A. They contain all the genetic information of an organism.

B. They produce the energy the cell needs to function.

C. They take the message of RNA back to the nucleus of the cell.

D. They lead to a particular function and trait in an organism.

The image below models a segment of DNA.

The label above each section of the model of DNA shows that segment's role within a particular cell.

Which of the following best describes the function of DNA within a cell?

A. The segments of DNA can have different functions within a cell.

B. Each segment of DNA has the same regulatory function within a cell.

C. All segments of DNA code for proteins within a cell.

D. Every segment of DNA must have a function within a cell.

Question 7 .

The table below shows the codons that make up the genetic code and the sequence of nucleotides that corresponds to them. To determine which amino acid corresponds to a codon, find the row matching the first RNA nucleotide, the column matching the second nucleotide, and the specific codon containing the third nucleotide.

What sequence of amino acids would be coded by the following set of nucleotides? AGU AUA UCG CGU UGU

A. Ser, Met, Leu, Gln, Cys

B. Arg, Leu, Ser, Asn, Stop

C. Arg, Thr, Lys, Thr, Gly

D. Ser, Ile, Ser, Arg, Cys

Which of these is true about DNA, proteins, and the expression of genetic traits?

A. Enzymes break down DNA, releasing amino acids that join to form proteins and express various traits.

B. Genes in DNA code for the production of proteins, which cause traits to be expressed.

C. DNA is mutated by a chemical passed from parents to offspring to form proteins that express traits.

D. Proteins bind to DNA, which activates them and forces them to express certain traits.

Question 9 .

The shape of a protein is determined by

A. the type of cell in which the protein was synthesized.

B. the sequence of amino acids that compose the polypeptide.

C. the lipid concentration in the immediate environment.

D. all of these

Question 10 .

Translation involves the assembling of proteins. Which of the following forms of RNA is responsible for carrying a formed amino acid to the protein assembly site during translation?

A. tRNA

B. mRNA

C. rRNA

D. RNA polymerase

Question 11 .

The DNA of a cell is organized into structures. What are these structures called?

A. nuclei

B. vacuoles

C. chromosomes

D. mitochondria

Which of the following is a true statement about codons?

A. In translation, an mRNA codon is recognized by its complementary tRNA.

B. In translation, an mRNA codon is recognized by its complementary amino acid.

C. A codon is a sequence of three amino acids.

D. A codon is a sequence of four nitrogenous bases.

Question 13 .

Which of the following best describes the product of DNA transcription?

A. a protein

B. an RNA molecule

C. a DNA molecule

D. a chromosome

Question 14 .

The cells within an organism contain the same DNA. However, many of the cells within an organism have different functions. For example, a kidney cell has a much different function than an eye cell.

What causes cells to have different functions despite having the same DNA?

A. Errors in the DNA cause some genes to be turned off.

B. Different genes are turned on in different cells.

C. Some cells have more than one copy of the DNA.

D. Every cell has different genes.

The image below is a model showing how chromosomes and DNA are structured within a cell.

Which letter represents a gene?

A. X

B. Y

C. Z

D. W

Question 16 .

All cells contain DNA, which provides information for the cells to make

A. different kinds of DNA.

B. different kinds of proteins.

C. new types of genes.

D. new types of organisms.

Question 17 .

In eukaryotic organisms, DNA transcription occurs in the ______of a cell.

A. ribosome

B. nucleus

C. cytoplasm

D. mitochondria

Which of the following are involved in RNA translation?

I. mRNA II. tRNA III. ribosomes IV. amino acids

A. I, III, and IV only

B. II, III, and IV only

C. I, II, III, and IV

D. III and IV only

Question 19 .

Ribosomes create, or synthesize, proteins through the use of DNA and RNA. Which of these is a step in protein synthesis?

A. The ribosome starts decoding when it attaches to the mRNA.

B. When the ribosome reads the last mRNA codon, it signals the end of translation.

C. The ribosome moves down the mRNA strand from one codon to the next as the tRNA brings each corresponding amino acid.

D. all of these

The codon chart below shows how different combinations of mRNA nucleotides code for various amino acids.

Which amino acids are coded for by an mRNA segment that reads AUC CGU?

A. tyrosine and alanine

B. tyrosine and arginine

C. isoleucine and alanine

D. isoleucine and arginine

Question 21 .

Which of the following correctly organizes genetic material from the broadest category to the most specific category?

A. genome chromosome DNA molecule gene

B. gene chromosome DNA molecule genome

C. genome chromosome gene DNA molecule

D. genome DNA molecule chromosome gene

Directions: Drag the nitrogenous bases to the correct locations on the image. Each base can be used more than once, but not all bases must be used.

Sections of a DNA strand and an incomplete RNA strand are shown in the diagram below. During RNA transcription, a DNA template strand is used to produce an RNA strand. Simulate the process of transcription by adding the remaining complementary nitrogenous bases to the RNA strand.

Question 23 .

What sequence of amino acids would be coded by the following set of nucleotides? AUG CCU ACG UGG GAC

A. Met, His, Ile, Stop, Asn

B. Ile, Pro, Leu, Cys, Glu

C. Met, Pro, Thr, Trp, Asp

Which of the following is true regarding the process shown above?

A. The process shown above is known as translation and involves the production of proteins from RNA.

B. The process shown above is known as replication and involves the production of DNA from RNA.

C. The process shown above is known as cloning and involves the production of RNA from protein molecules.

D. The process shown above is known as transcription and involves the production of proteins from DNA.

Question 25 .

Which of the following best describes the process of transcription during protein synthesis?

A. to pair tRNA with mRNA

B. to produce anticodons that will be delivered to the ribosome

C. to deliver amino acids to the nucleus

D. to make an RNA copy of a gene's DNA sequence

Question 26 .

Proteins play a vital role in all cells. In fact, cells need thousands of proteins in order to function properly. What primarily directs the synthesis of proteins?

A. the cytoplasm found throughout a cell

B. the folding patterns of strands of RNA

C. the genetic information stored in DNA

D. the energy that is stored in mitochondria

The picture below shows the process of transcription.

During transcription, enzymes bind to a molecule of DNA. Then, the enzymes unwind and separate the DNA's double helical strands. As the molecule unwinds, complementary nucleotides pair with one of the DNA strands to form

A. an RNA molecule.

B. an identical strand of DNA.

C. a protein molecule.

D. a DNA polymerase.

Question 28 .

Every trait you see on an organism is a result of that organism's DNA instructing the organism's cells. How does the information stored in DNA's nucleotides translate into traits such as eye color and ear shape?

A. Traits are determined by the presence or absence of lac operons along a series of nucleotides.

B. Traits are determined by codons that are broken apart to form proteins.

C. Traits are determined by a group of enzymes known as DNA helicases.

D. Traits are determined by proteins that are built according to the instructions stored in genes.

Question 29 .

DNA contains all the information a cell needs in order to make certain proteins. Where are the protein-synthesizing instructions stored on a DNA molecule?

A. Every gene on certain chromosomes codes for the production of different kinds of uracil, which then promotes protein synthesis.

B. The phosphate group in a strand of DNA codes for the production of amino acids.

C. The deoxyribose portion of certain genes codes for the production of certain proteins.

D. Certain sequences of nucleotides code for the production of specific proteins.

In which of the following ways does genetic information typically flow in an organism?

A. proteins RNA DNA

B. DNA RNA proteins

C. RNA proteins DNA

D. DNA proteins RNA

1. A

2. D

3. B

4. B

5. D

6. A

7. D

8. B

9. B

10. A

11. C

12. A

13. B

14. B

15. C

16. B

17. B

18. C

19. D

20. D

21. A

22. --

23. C

24. A

25. D

26. C

27. A

28. D

29. D

30. B

DNA

Answer the questions below.

1. Which nitrogenous base is the complementary base for thymine?

Adenine

2. Which nitrogenous base is the complementary base for guanine?

Cytosine

3. Which parts of a nucleotide make up the backbone of the DNA helix?

Deoxyribose sugar and phosphate group

4. The DNA molecule is in the shape of a double helix and coils itself upon histone proteins. Why are these features important to DNA?

The length of the DNA would be too long to fit into the nucleus of the cell if it were not able to twist, bend, and spiral upon itself or the histone proteins.

5. What type of bond can be found between complementary nitrogenous bases? Why is this type of bond significant to the DNA?

There are hydrogen bonds between the complementary bases. These bonds are very important because they are weak bonds and are, therefore are easily broken. This quality allows the DNA to “unzip” itself during replication. DNA

DNA, continued

3. phosphate

1. condense 2. double helix makes up backbone

deoxyribose why sugar shape is

4. histone coiled contain made of around DNA contain

5. nucleotides carries

6. hereditary information contain nitrogenous bases on 8. adenine

7. genes pairs with

thymine guanine pairs with 9. cytosine DNA

DNA

Answer the questions below.

Which nitrogenous base is the complementary base for thymine?

Which nitrogenous base is the complementary base for guanine?

Which parts of a nucleotide make up the backbone of the DNA helix?

The DNA molecule is in the shape of a double helix and coils itself upon histone proteins. Why are these features important to DNA?

What type of bond can be found between complementary nitrogenous bases? Why is this type of bond significant to the DNA?

1 DNA

DNA, continued

Using all of the following terms in the word bank, complete the graphic organizer.

Word Bank adenine condense cytosine double helix genes hereditary information histones nucleotides phosphate

3.______

1.______2.______makes up backbone deoxyribose sugar why shape is coiled 4.______contain around made of DNA contain

5. ______carries

6.______contain nitrogenous bases using 8.______

7.______pairs with

thymine guanine pairs with 9.______

2 DNA

INSTRUCTIONS: Use the words in the box below to fill in the blanks based on what you have learned about DNA. Words may be used more than once or not used at all.

Word Bank

adenine backbone deoxyribose guanine helix inheritance hydrogen nucleotides phosphate strands

CLOZE 1 The building blocks of DNA are called ______. Nucleotides consist of three main parts: a sugar, a______group, and a nitrogenous base.

The sugar is ______; it is a pentose sugar, which means it has five carbon atoms. There are four nitrogenous bases that can be found in DNA: adenine, thymine, cytosine, and ______. DNA’s ______is made of the sugars and phosphates, while the nitrogenous bases create the inner piece of the structure.

DNA is made of two ______. These strands are linked together by weak

______bonds between the nitrogenous bases forming the structure that resembles a twisted ladder or double ______. Each nitrogenous base has its own complementary base: ______bonds with thymine and cytosine bonds with guanine.

1 DNA

INSTRUCTIONS: Use the words in the box below to fill in the blanks based on what you have learned about DNA. Words may be used more than once or not used at all.

Word Bank bond genes heredity histone hydrogen nitrogenous nucleus polynucleotide protein sequence

CLOZE 2 DNA carries the genetic information that controls ______. The portions of

DNA that carry the genetic information are called ______, the basic unit of inheritance. Each gene codes for a specific ______that determines the physical characteristics of an organism. DNA molecules are very long, but they have a special technique that allows them to fit into the cells. The DNA helix is able to twist so it wraps itself around ______proteins, causing the molecule to become super-coiled. DNA is found in the ______of a eukaryotic cell or floating throughout a prokaryotic cell. Whether the cell is from an animal, a plant, a protist, a fungus, or a bacterium, they all contain DNA. This DNA is similar regardless of the organism; it contains the same

______bases. The differences within the organisms are determined by the number of genes and the ______of the nitrogenous bases that create those genes.

2 DNA

INSTRUCTIONS: Use the words in the box below to fill in the blanks based on what you have learned about DNA. Words may be used more than once or not used at all.

Word Bank adenine amino acids cytosine genes heredity hydrogen nucleotides organisms thymine uracil

CLOZE 3 There are 5 different nitrogenous bases that can be found in nucleic acids. The base,

______, is found only in DNA. The base that is found only in RNA is

______. The other three bases can be found in both DNA and

RNA. ______is hydrogen bonded to thymine in DNA and to uracil in

RNA. ______is hydrogen bonded to guanine in both DNA and RNA.

Portions of DNA contain the template for a protein; the nitrogenous bases determine the

______that make up the protein. These portions of DNA are called

______and are known as the basic unit of inheritance.

3 DNA

Triangle Vocabulary

This model serves as the pieces to cut out as well as the Answer Key.

thymine sugar

shape double helix double

deoxyribosesugar

deoxyribose

guanine guanine

cytosine

backbone adenine

sugar- phosphate sugar-

thymine sugar- phosphate sugar-

histone

thymine cytosine

protein protein guanine

adenine histone double helix double

shape backbone adenine

1 Finish BIO 3C.3 Gene Mutations

A change in the sequence of an organism's genetic material is known as a mutation. Genetic Instructions & Codons

The sequence of the nucleotides within a strand of DNA provides the genetic instructions needed to construct proteins. In order to express these proteins, a segment of DNA must first be transcribed, or copied, to a complementary strand of messenger RNA (mRNA). After transcription, the mRNA moves from the nucleus to the cytosol where the mRNA's codons, or triplet nucleotide sequences, are translated into functional proteins. Each codon corresponds to a specific amino acid which can then be joined together to form long chains that make up protein molecules. DNA sequences make up the genetic code of an organism and determine which traits the organism will exhibit. Proteins carry out the instructions coded by these DNA sequences.

This chart shows the codons that code for specific amino acids. Sources of Mutations

Mutations can occur randomly during DNA replication when base pairs are inserted, deleted, or substituted, or they can be caused by environmental factors, such as overexposure to radiation or toxic chemicals. ORIGINAL DNA

Mutations can occur in any cell in an organism's body, but they can only be passed on to an organism's offspring if the mutation occurs in the sex cells (gametes) of the organism. If a mutation occurs in the body cells of an organism, such as skin cells, bone cells, muscle cells, and nerve cells, it cannot be passed on to potential offspring. These mutations can only be passed on to the mutant body cells' daughter cells (cells that are produced when the mutant cell divides). Spontaneous Mutations — Mutations that occur during DNA replication are said to be spontaneous. Cells have a mechanism that essentially proofreads and repairs strands during replication. DNA polymerase is responsible for adding new nucleotides to a DNA strand. In almost all cases, it only adds a nucleotide if the previous nucleotide correctly pairs with its complementary base. If a nucleotide is mismatched, the DNA polymerase will backtrack and correct the error. As a result, only one in many millions of errors make it to the final stage of replication and become mutations. Induced Mutations — Mutations can be also be induced by environmental factors, such as overexposure to radiation or toxic chemicals. Any factor that is a potential source of mutations is known as a mutagen. Point Mutations

A point mutation is a mutation caused by the substitution of a single base pair for another. Some genetic diseases, like cystic fibrosis, color blindness, hemophilia, and sickle cell anemia, can occur as a result of a point mutation.

The image below demonstrates an example of a point mutation. Notice how the substitution of a single base pair results in a different amino acid. The remainder of the protein sequence remains unchanged.

A silent mutation is a specific type of point mutation. Because many amino acids have more than one codon, it is possible for a mutation in a single base pair to have no effect on the polypeptide sequence.

The example below shows a silent mutation. Though the second codon, or triplet code, has changed, the amino acid sequence of the resulting protein is the same as that coded for by the normal mRNA strand.

A nonsense mutation changes an amino acid codon into a stop codon. This causes the normal polypeptide sequence and the resulting protein to be shorter than usual. Almost all truncated proteins are nonfunctional and may lead to serious genetic conditions.

Frameshift Mutations A frameshift mutation is caused by the addition or removal of one or more base pairs so that the reading frame of a codon sequence is shifted. The addition of nucleotides to a sequence is called an insertion. The removal of nucleotides from a sequence is called a deletion.

Since a codon is a sequence of three nucleotides that code for a specific amino acid, any insertion or deletion of nucleotide base pairs that are not in multiples of three will cause a frameshift mutation. Insertions or deletions in multiples of three will cause a protein to be shorter or longer than normal, but the entire sequence of the amino acids will not be shifted.

The image below shows how insertions and deletions affect the polypeptide sequence.

Effects of Mutations

Proteins determine the traits and activities, and therefore the phenotype, of a cell. If a sequence of DNA is changed, the result can be a change to the type of protein that is formed or the amount of protein produced. The outcome of such changes can vary from beneficial to neutral to negative depending on the effect they have on the protein being produced.

Neutral Effect - A mutation is neutral if it has no noticeable effect on the phenotype of an organism. The mutation, for example, may have occurred in a section of DNA that does not code for proteins, or it may have occurred in a protein-coding region but does not alter the amino acid sequence of the protein. Beneficial Effect - Some mutations actually enhance an organism's ability to survive. Those beneficial changes can be maintained through natural selection and result in evolutionary change. An example of a beneficial mutation is one that gives some bacteria the ability to resist antibiotics. Those bacteria are able to survive and pass this resistant trait on to their offspring. In a similar way, some insects and other organisms have the ability to resist pesticides as a result of mutations. An example of a different kind of benefit occurs when a mutation for a disorder gives an individual an advantage against another disorder. Sickle cell disease results from a mutation that affects the shape of red blood cells. People with sickle cell disease are born with two mutated copies of the gene that codes for the hemoglobin protein, which causes their red blood cells to become sickle- shaped. Individuals with the disease often suffer pain in their extremities due to the build-up of these cells in the blood vessels. The shape of the blood cells also reduces the amount of oxygen transported in the blood. Sickle cells, however, are not good hosts for malaria parasites, so people with sickle-cell disease (homozygous for the trait) or carriers (heterozygous for the trait) have increased resistance to malaria.

People who are homozygous for normal red blood cells are excellent hosts for malaria and therefore contract the disease at a higher rate. Therefore, heterozygotes, who retain the benefit of the sickle cell gene but do not develop sickle cell disease, are more likely to survive than their homozygous counterparts in regions where malaria is endemic.

Negative Effect — Mutations that cause disease or increase the likelihood of developing disease by leading to non-functional or dysfunctional proteins are considered negative. For example, cystic fibrosis is a genetic disorder affecting the respiratory and digestive systems. People with this disorder inherit a faulty chromosome #7. This chromosome produces a protein that transports sodium chloride through the plasma membrane. If the protein does not function properly, the movement is blocked and a thick, sticky mucous forms on the outside of the cell. Cells in the lungs are most seriously affected, increasing the risk of infection. In addition, ducts in the pancreas can become blocked so digestive enzymes are prevented from reaching the small intestine.

BIO 3C3 Question 1 .

A codon is a set of three nucleotides that correspond to a specific amino acid. The table below shows various DNA codons and their corresponding amino acids.

Amino Acid DNA Codon(s) Alanine GCT, GCC, GCA, GCG Arginine AGA, AGG, CGT, CGC, CGA, CGG Asparagine AAT, AAC Aspartic Acid GAT, GAC Cysteine TGT, TGC Glutamic Acid GAA, GAG Glutamine CAA, CAG Glycine GGT, GGC, GGA, GGG Histadine CAT, CAC Isoleucine ATT, ATC, ATA Leucine CTT, CTC, CTA, CTG, TTA, TTG Lysine AAA, AAG Methionine (Start) ATG Phenylalanine TTT, TTC Proline CCT, CCC, CCA, CCG Serine TCT, TCC, TCA, TCG, AGT, AGC Threonine ACT, ACC, ACA, ACG Tryptophan TGG Tyrosine TAT, TAC Valine GTT, GTC, GTA, GTG Stop TAA, TAG, TGA

Two strands of DNA are identical except for one codon. As a result, they code for slightly different proteins. Based on the information in the table above, which of the following statements could be true?

A. One strand contains a CAC codon instead of CTC.

B. One strand contains a ACG codon instead of ACA.

C. One strand contains a CCC codon instead of CCA.

D. One strand contains a CGC codon instead of CGG.

Dr. Stevens is examining the DNA sequences of a group of mice. He notices that in one of the mice, one nucleotide has been substituted with another in the part of the DNA sequence that codes for fur color. However, despite the substitution, the mouse still has the same fur color as the other mice that have the typical DNA sequence.

What best explains why the nucleotide substitution in the mouse does not change its phenotype?

A. Substitutions in the nucleotides in the DNA of the mouse can affect its genotype but rarely affect its phenotype.

B. The substituted nucleotide produces codons that correspond to the same amino acid that is found in the other mice.

C. The mouse has a completely different DNA sequence than the other mice.

D. DNA sequences do not determine the color of a mouse's fur.

Question 3 .

Some mice have inherited a genetic mutation that causes them to have a band of white fur around the middle of their bodies. What is most likely true about an ancestor of these mice?

A. A change in its environment changed the DNA of only part of its body.

B. A change in its fur color modified the structure of its DNA.

C. A change in its food source affected only the fur around its stomach.

D. A change in its DNA resulted in a modified protein that controls fur color.

The codon chart relates amino acids to the mRNA codons that specify them.

mRNA Codon Chart

Image courtesy of NIH

A DNA triplet has the sequence 3′-ATC-5′. After a single base mutation, the DNA triplet produces an mRNA codon that specifies the amino acid tryptophan (Trp).

What mutation did the DNA triplet undergo?

A. The nucleotide A was replaced with C.

B. The nucleotide C was replaced with G.

C. The nucleotide A was replaced with T.

D. The nucleotide T was replaced with C.

Question 5 .

A mutation in a plant's cell changes the gene that codes for a certain protein, and as a result the cell can no longer make the protein. The gene sequences before and after the mutation are shown in the following table.

Sequence before the mutation: A–T–T–A–T–C–A–T–A Sequence after the mutation: A–T–T–T–A–G–A–T–C–A–T–A

What kind of mutation is shown in the table?

A. substitution

B. deletion

C. insertion

D. frameshift

In what way can DNA segments be changed such that genes are altered or mutated?

I. New DNA segments can be inserted. II. New DNA segments can be substituted. III. DNA segments can be deleted.

A. I and II only

B. I, II, and III

C. II and III only

D. I only

Question 7 .

The chart below shows the codons that make up the genetic code and the sequence of nucleotides that corresponds to them.

A mistake during DNA replication leads to a mutation in the nucleotide sequence shown below.

What kind of mutation will result from the mistake made during DNA replication in the nucleotide sequence above?

A. a chromosomal mutation

B. a silent mutation

C. a frame shift mutation

D. a nonsense mutation

A sequence of DNA in the nucleus of a cell is given below. CAG TGT ATC The cell is exposed to radiation and the sequence of DNA mutates as shown below. CAG ATG TAT C What type of mutation occurred in the DNA sequence?

A. addition

B. duplication

C. deletion

D. substitution

Question 9 .

Directions: Select each correct answer. More than one answer may be correct.

Mutations occur when segments of DNA are accidentally rearranged through the deletion, insertion, or substitution of one or more nucleotides. The diagram below shows how a nucleotide sequence can be changed by these mutations.

If one or more of these mutations occurs in the genes of reproductive cells, how might the traits of offspring be affected?

They may not be affected at all.

They may receive a benefit.

They may be harmed.

Question 10 .

A genetic mutation that causes a codon that should code for a specific amino acid to be changed into a stop codon results in a shortened protein product and is known as

A. a frame shift mutation.

B. a chromosomal mutation.

C. a silent mutation.

D. a nonsense mutation.

Mutations can occur randomly during DNA replication. Suppose DNA replication is occurring in a cell. If DNA replication occurs correctly, the following strand will be produced.

If a substitution mutation occurs during DNA replication, which of these could represent the mutated strand produced instead?

Question 12 .

Mutations can occur randomly during DNA replication. Suppose DNA replication is occurring in a cell. If DNA replication occurs correctly, the following strand will be produced.

If a point mutation occurs during DNA replication, which of these could represent the mutated strand produced instead?

Question 13 .

Chromosomes contain genes, and genes determine an organism's characteristics. Sometimes mutations occur in which the sequence of nucleotides within a gene becomes altered. Which of the following describes how a gene mutation would most likely affect an organism?

A. It would cause different proteins to be produced during translation.

B. It would cause the codons produced to be more or less than 3 nucletoides in length.

C. It would cause the wrong type of nucleic acid to be incorporated into the organism's genes.

D. It would cause the sugar-phosphate backbone of all of the organism's DNA to be modified.

The chart below shows the codons that make up the genetic code and the sequence of nucleotides that corresponds to them.

A mistake during DNA replication leads to a mutation in the nucleotide sequence shown below.

What kind of mutation will result from the mistake made during DNA replication in the nucleotide sequence above?

A. nonsense mutation

B. chromosomal mutation

C. silent mutation

D. frame shift mutation

Question 15 .

A mutation in a bacteria cell changes the gene that codes for a certain protein, and as a result the bacteria produces a different protein. The gene sequences before and after the mutation are shown in the table below.

Sequence before the mutation: A–T–A–G–G–C–G–G–C–T–A–G Sequence after the mutation: A–T–A–G–G–C–T–A–G

What type of mutation caused the cells to start making a different protein?

A. frameshift

B. deletion

C. insertion

A researcher is investigating a short DNA segment within a gene. When translated, the DNA segment produces a peptide chain with the sequence Met-Ala-Pro-Gly-Ser. The researcher has identified an insertion mutation that changes this segment of DNA to the segment given.

Mutated DNA segment: 3′-TACCCGAGGGCCTTC-5′

mRNA Codon Chart

Image courtesy of NIH

According to the mRNA codon chart, what is the sequence of the peptide chain produced when the mutated DNA segment is translated?

A. Met-Pro-Arg-Ala-Phe

B. Met-Gly-Ser-Arg-Lys

C. Met-Pro-Arg-Ala-Lys

D. Met-Cys-Ser-Arg-Tyr

Directions: Select ALL the correct answers.

An mRNA codon chart is shown below.

Suppose a DNA triplet has the sequence 3′-ATG-5′. Which of these three possible mutations of the triplet will stop translation?

3′-ATT-5′

3′-ACG-5′

3′-ATC-5′

A codon is a set of three nucleotides that correspond to a specific amino acid. The table below shows various DNA codons and their corresponding amino acids.

In the DNA strand below, two nucleotides were reversed during replication.

What will happen when the replicated DNA strand is translated into a protein?

A. Tyrosine will be added instead of isoleucine.

B. Nothing will happen.

C. No amino acids will be added at all.

D. The same amino acid, isoleucine, will be added.

Question 19 .

Which of the following mutations is most likely to result in a heritable change?

A. radiation from x-rays causes a mutation in a brain cell

B. ultraviolet light from the Sun causes a mutation in a skin cell

C. a chemical in cigarette smoke causes a mutation in a lung cell

A genetic mutation that does not result in a change in the amino acid sequence of the resulting protein is called

A. a nonsense mutation.

B. a chromosomal mutation.

C. a frame shift mutation.

D. a silent mutation.

1. A

2. B

3. D

4. D

5. C

6. B

7. D

8. A

9. --

10. D

11. D

12. A

13. A

14. C

15. B

16. B

17. --

18. A

19. D

20. D

Name: ______Block: ______Date: ______

Worksheet: Mutations Practice

There are three ways that DNA can be altered when a mutation (change in DNA sequence) occurs. 1. Substitution – one base-pairs is replaced by another: Example: G to C or A to G C G T C 2. Insertion – one or more base pairs is added to a sequence: Example: CGATGG –– CGAATGG GCTACC GCTTACC 3. Deletion – one or more base pairs is lost from a sequence: Example: CGATGG –– CATGG GCTACC GTACC There are five possible results of a mutation. 1. Silent mutation: When a base pair is substituted but the change still codes for the same amino acid in the sequence: Example: TCT and TCC both code for the amino acid Serine 2. Substitution: When a base pair is substituted and the new codon codes for a different amino acid: Example: TCT codes for Serine and CCT codes for Proline 3. Premature Stop: When a substitution results in the formation of a STOP codon before all of the codons have been read and translated by the ribosome. Example: GTGGTCCGAAACACC –– GTGGTCTGAAACACC Val-Val-Pro-Asn-Thr Val-Val-STOP 4. Codon Deletion or Insertion: A whole new amino acid is added, or one is missing from the mutant proton: Example: GTGGTCCGAAACACC –– GTGGTCTGCCGAAACACC Val-Val-Pro-Asn-Thr Val-Val-Cys-Pro-Asn-Thr 5. Frame Shift: When a deletion or insertion results in a different base pait being the beginning of the next codon, changing the whole sequence of amino acids Example: GTGGTCCGAAACACCT –– GTGGTCGAAACACCT Val-Val-Pro-Asn-Thr Val-Val-Glu-Thr-Pro

Ms. DR’s Biology 621

Name: ______Block: ______Date: ______

1. Below is the base sequence for the normal protein for normal hemoglobin and the base sequence for the sickle cell hemoglobin.

Normal: GGG CTT CTT TTT Sickle: GGG CAT CTT TTT

a. Transcribe and translate the normal and sickle cell DNA.

b. Identify this as a point or frameshift mutation. Explain.

c. If the base sequence read GGG CTT CTT AAA instead, would this result in sickle cell hemoglobin? Explain.

Ms. DR’s Biology 621

Name: ______Block: ______Date: ______

2. There are several types of genetic mutations. List two. What do they have in common? How are they different? Give an example of each.

3. A geneticist found that a particular mutation had no effect on the protein coded by a gene. What do you think is the most likely type of mutation in this gene? Why?

4. Name one amino acid that has more than one codon. Name an amino acid that has only one codon

5. Look at the following sequence: THE FAT CAT ATE THE RAT. Delete the first H and regroup the letters in groups of three- write out the new groups of three. Does the sentence still make sense? What type of mutation is this an example of?

You have a DNA sequence that codes for a protein and is 105 nucleotides long. A frameshift mutation occurs at the 85th base- how many amino acids will be correct in this protein?

6. Given the following three mRNA sequences, 2 code for the same protein. Which two?

#1. AGU UUA GCA ACG AGA UCA

#2 UCG CUA GCG ACC AGU UCA

#3 AGC CUC GCC ACU CGU AGU

Ms. DR’s Biology 621

Name: ______Block: ______Date: ______

Original DNA Sequence: T A C A C C T T G G C G A C G A C T mRNA Sequence: Amino Acid Sequence:

Mutated DNA Sequence #1: T A C A T C T T G G C G A C G A C T What’s the mRNA sequence? (Circle the change) What will be the amino acid sequence? Will there likely be effects? What kind of mutation is this?

Mutated DNA Sequence #2: T A C G A C C T T G G C G A C G A C T What’s the mRNA sequence? (Circle the change) What will be the amino acid sequence? Will there likely be effects? What kind of mutation is this?

Mutated DNA Sequence #3: T A C A C C T T A G C G A C G A C T What’s the mRNA sequence? (Circle the change) What will be the amino acid sequence? Will there likely be effects? What kind of mutation is this?

Mutated DNA Sequence #4: T A C A C C T T G G C G A C T A C T What’s the mRNA sequence? (Circle the change) What will be the amino acid sequence? Will there likely be effects? What kind of mutation is this?

Mutated DNA Sequence #5: T A C A C C T T G G G A C G A C T What will be the corresponding mRNA sequence? What will be the amino acid sequence? Will there likely be effects? What kind of mutation is this?

Ms. DR’s Biology 621

Name: ______Block: ______Date: ______

1. Which type of mutation is responsible for new variations (alleles) of a trait? 2. Which type of mutation results in abnormal amino acid sequence? 3. Which type of mutation stops the translation of the mRNA?

DNA Technology

DNA technology includes methods used to investigate an organism's genetic material and methods used to alter an organism's genetic material in order to produce a desired trait or outcome. DNA Technology Farmers and ranchers were perhaps the first genetic engineers. By selecting certain crops or animals to breed based on their desirable traits (e.g. the strongest bull, the fastest horse, the most disease-resistant corn, the largest tomato, etc.), farmers and ranchers were unknowingly practicing a form of artificial selection known as selective breeding. Over time, the frequency of desired traits in a selectively bred population increases, while the frequency of unwanted traits decreases.

Although selective breeding had been around for centuries, it was Charles Darwin's studies on evolution and Gregor Mendel's discovery of genetic alleles that helped to explain the scientific mechanisms behind the manipulation of genes. Once people realized the potential of such practices, the field of genetic engineering was born. The Human Genome Project In 1980, scientists began mapping the human genome. The Human Genome Project was a thirteen-year-long research effort that included scientists from several countries around the world. The main goal of the Human Genome Project was to sequence all of the base pairs that compose human DNA. This process is called DNA sequencing, while the process of determining all of the base pairs that make up a specific gene is called gene sequencing. Scientists hoped that a greater knowledge of how genes control biological processes in the human body would help them alleviate or even cure certain diseases. The following video discusses the results of the Human Genome Project, their potential applications, and the possible implications of this knowledge on society. Clip provided by Education Clip Library with permission from ITN Source The information uncovered by the Human Genome Project has equipped researchers and doctors with many new tools. Current applications of genetic engineering attempt to not only improve the quality of life of humans, but to reveal useful genetic information that can be used to help prevent or treat disease.

The completion of the Human Genome Project has enabled individualized gene sequencing. The data collected from gene sequencing has led to the identification of genes associated with certain diseases. Now, individuals can have their genomes sequenced to screen for the presence of these disease alleles. The identification of disease alleles has allowed scientists to begin developing gene therapy techniques. These techniques, many of which are still in experimental stages, involve targeting or replacing the genes involved with diseases. Scientists are working on several approaches to gene therapy: o Replacing mutated or non-functioning genes with a healthy copy. o Inactivating genes that are working incorrectly. o Inserting a new gene to help an individual fight a disease. The Human Genome Project has also made human transcriptomic and proteomic studies possible. A transcriptome shows all of the RNA transcripts produced by an individual, while a proteome shows all of the proteins produced by an individual. Combining transcriptomic and proteomic studies allows scientists to identify the functions of certain genes, along with factors that regulate gene expression. Such studies can also be used to investigate how gene expression is altered in individuals with certain diseases or conditions. This information can ultimately be used to diagnose diseases or design treatment methods for them. Other applications of the Human Genome Project include recombinant DNA technology, cloning, and DNA fingerprinting. Recombinant DNA Technology In the mid 1980s, a researcher named Paul Boyer and his colleagues discovered a class of enzymes that are able to cut DNA sequences at different points, much like scissors. Using these restriction enzymes, specific sequences can be cut from a length of DNA. Combined with the knowledge gained from the Human Genome Project, this technique revolutionized genetic engineering and led to recombinant DNA technology. Recombinant DNA technology involves the alteration of an organism's original genetic material through the insertion or substitution of DNA segments (or gene splicing). Typically, these modifications are made in order to somehow enhance the organism. For example, crops, such as tomatoes, corn, and cotton, or animals, such as cattle and sheep, can be genetically modified to be more resistant to diseases that often affect them. Genetic modification requires extensive knowledge of an organism's genome, however, because genes cannot be safely manipulated without knowing the potential outcome of such changes — and even then, the long-term consequences are often unknown. In many applications of recombinant DNA technology, genetic material from one organism is transferred into the DNA of a different organism in order to produce some desired outcome. One of the most famous examples of this technique involved the insertion of a human gene into bacteria for the purpose of producing inexpensive human insulin — an achievement that greatly improved the treatment of people with diabetes. When the genetically modified organism carries DNA from two different species, it is called a transgenic organism. An example of recombinant DNA technology using a bacterium is shown below.

Once its genetic material is altered, the bacterium will begin to produce the desired gene product.

A promising application of recombinant DNA technology involves the insertion of human gene sequences into an individual's cells and tissues to replace a defective or mutant allele. This process is known as gene therapy. To deliver the functional gene, scientists usually splice it into the genetic material of a virus that has been rendered harmless. Early studies have confirmed that gene therapy has the potential to cure certain genetic disorders. Genetic Fingerprinting In 1983, a biochemist named Kary Mullis invented a technique called the polymerase chain reaction (PCR) that would go on to be indispensable in the field of biotechnology. PCR enables very small samples of DNA to be multiplied by a factor of millions in a very short time. The technique involves isolating the desired DNA sequence, then using special DNA polymerase enzymes to copy the sequence. Each copy is then copied, amplifying the DNA sample exponentially. A few of the many applications of PCR technology include generating sufficient DNA samples for genome sequencing and the diagnosis of genetic disease, but perhaps the most well known use of PCR is for genetic fingerprinting. Genetic fingerprinting (or DNA profiling) is the use of genetic markers to create a profile of an individual's DNA. This technology was developed in 1984 by a man named Sir Alec Jeffreys. Genetic fingerprints can be compared to confirm the identity of an individual (thus the name fingerprint) or to determine the relatedness between two individuals. To obtain a genetic fingerprint, a sequence of DNA that is highly variable in humans is obtained from an individual and cut into pieces with very specific restriction enzymes. Gel electrophoresis is then used to create the fingerprint. In gel electrophoresis, a sample of DNA is placed in a gel tray and an electric current is applied to the gel. This causes the electrically charged DNA fragments to be pulled through the gel at different rates depending on their size. Because the gel impedes the movement of the fragments, smaller fragments move faster and farther than larger ones. The gel is then viewed under ultraviolet light to reveal the final locations of the fragments in the gel, called "bands."

During gel electrophoresis, samples of DNA are placed into a gel medium and exposed to an electric current.

If two individuals have similar DNA sequences, the restriction enzymes will have cut their sequences in similar places, and the genetic fingerprints of the individuals will look very similar. The more bands the individuals share, the higher their degree of relatedness. If the genetic fingerprints are identical, then the DNA used to create them must have come from the same individual. Genetic fingerprinting technology is so sensitive that it is now routinely used by forensic scientists to confirm or rule out the presence of a suspect at a crime scene.

Genetic fingerprinting is a powerful tool that can show the degree of relatedness among several individuals. Cloning The process through which an existing cell, tissue, organ, or organism is used to artificially produce a genetically identical copy is known as cloning. In 1996, a group of scientists in Edinburgh, Scotland announced they had successfully cloned the first mammal — a sheep by the name of Dolly. This was achieved by implanting the nucleus of a donor adult cell in a developing egg cell, ultimately resulting in the birth of an animal with DNA identical to that of the donor cell. Cloning is a scientific breakthrough that holds the potential for many beneficial applications, such as cloning organs for transplant recipients or cloning animals to save endangered species, but the technology is not yet perfect. Dolly only lived six years before she had to be euthanized from complications of advanced lung disease and arthritis. Many cloned organisms exhibit a higher rate of genetic disorders and health problems. These concerns, as well as the unease many people have about cloning humans, have made cloning a controversial technology. With additional research, however, cloning may have many important medical and agricultural applications in the future.

These four clones were made using Dolly's DNA. Genetically, they are identical to the original Dolly.

Ethics of Biotechnology

Ethics concern the difference between fair and unfair, good and bad, or responsible and irresponsible actions. As biotechnology is developed, there may be ethical arguments to be considered regarding their application. Ethics and Science There are ethical limits on the kinds of research scientists can perform. It is unethical for scientists to perform experiments that could harm human beings unless the subjects are voluntary and are fully knowledgeable of any possible consequences from the experiments. There are many laws that govern the use of humans in experiments. Ethical concerns have been raised along with the advancement of biotechnology. The application of biotechnology has both benefits and drawbacks. As new technologies and methods are developed, there are also ethical arguments for and against their use. Stem Cells Stem cells are undifferentiated cells that have the potential to become specialized in structure or function. Stem cells are primarily found in embryos, although they can also be found in adults (e.g., in bone marrow). Adult stem cells are harder to isolate than embryonic stem cells, however.

Since stem cells have the potential to become any type of cell, scientists hope that by injecting or transplanting stem cells into diseased or damaged tissue, the stem cells can replace abnormal or missing cells. For example, stem cells may some day be used to replace damaged heart muscle tissue or brain tissue. Some success has been seen with bone marrow transplants, a form of stem cell therapy that is used to replace cells that are damaged during cancer treatments. Bone marrow transplants have also been used for years to treat leukemia, sickle cell anemia, and disorders affecting the immune system.

Although there are many potential benefits to stem cell research, there is also much controversy regarding the ethical use of stem cells. This controversy results from different opinions on the acquisition and use of embryonic stem cells for scientific and medical studies. Obtaining these cells typically requires the destruction of an early-stage embryo, which some individuals view as a human life. Also, to be useful in scientific and medical studies, researchers would need to create clones of the stem cells. While this type of cloning would be simply for research and the development of therapies, some worry that it would lead to greater acceptance of cloning for reproductive purposes. To date, representatives from the political and scientific communities have not succeeded in persuading dissenters that scientific use of cloning will not lead to the reckless, unethical use of the technique. Genetically Modified Organisms Genetically modified organisms are organisms whose DNA has been altered or manipulated. All genetic modification techniques involve inserting, deleting, or substituting DNA segments into an organism's natural genomic material. Typically these modifications are made in order to somehow enhance the organism. For example, crops, such as tomatoes, corn, and cotton, or animals, such as cattle and sheep, can be genetically modified to be more resistant to diseases that often infect them. Genetic modification techniques require extensive knowledge of the organism's genome, however, because genes cannot be safely manipulated if the traits that they express are unknown.

Even complete understanding of gene functionality cannot prevent problems from occurring. There are still risks involved with the introduction of genetically modified organisms. Engineered crops pose the danger of spreading and reproducing with wild types. In addition, the modifications may not necessarily work. Just as insects can become resistant to chemical pesticides, there is the same risk that they could become resistant to chemicals produced due to the insertion of genes from other organisms.

BIO 3C4 Question 1 .

Recently, scientists have genetically engineered fruit crops to contain vaccines. How might these fruit crops most likely benefit society?

A. They could help eradicate all infectious diseases in the world.

B. They could make it cheaper and easier to administer vaccines.

C. They could make fruit crops more productive than they were before.

D. They could encourage people to eat healthier food.

Question 2 .

What was produced as a result of the Human Genome Project?

A. mutant cells containing human DNA

B. clones using human embryonic DNA

C. stem cells from the human genome

D. a gene map of the human genome

Question 3 .

Severe Combined Immunodeficiency (SCID) is a group of genetic disorders characterized by a lack of functional immune cells in the body. In one type of SCID, a person inherits a mutation in the gene that makes ADA, an enzyme needed for the production of white blood cells. A person who inherits this mutation cannot produce enough healthy white blood cells to protect themselves against disease. How could scientists use gene therapy to effectively treat this type of SCID?

A. Scientists could transplant new genes into the person's genome to deactivate the mutated SCID genes.

B. Scientists could delete the mutated ADA gene from the DNA sequence of a person with SCID.

C. Scientists could sequence a person's genome to determine the location of the mutated ADA gene.

D. Scientists could use stem cells to transplant healthy white blood cells into people who have SCID.

A new species has been discovered. Scientists have obtained a DNA profile of the organism and are comparing it to the profiles of other known species.

The new species is most closely related to the

A. koala bear.

B. aardvark.

C. wren.

D. guinea pig.

Question 5 .

Gel electrophoresis is a process that allows scientists to compare the DNA of organisms. The first step of gel electrophoresis is to use enzymes to cut DNA into different-sized fragments, and the next step involves using an electric current to push the DNA fragments along a gel. Which of the following statements correctly describes how the DNA fragments travel along the gel?

A. Long DNA fragments move farther along the gel than shorter DNA fragments.

B. Neutral DNA fragments move farther along the gel than positively charged DNA fragments.

C. Short DNA fragments move along the gel faster than longer DNA fragments.

D. Positively charged DNA fragments move along the gel faster than neutral DNA fragments.

Stem cells are undifferentiated cells. They have the potential to become any type of cell in the body. They are already used in treating many diseases, and scientists hope to learn how to use them to regenerate damaged or destroyed parts of the body.

Which of the following sources of stem cells presents the greatest ethical problems or controversies?

A. Stem cells can be created from many types of cells in adults, such as skin cells.

B. Stem cells can be harvested from umbilical cord blood after the birth of a baby.

C. Stem cells can be harvested from certain tissues and organs in adults, such as bone marrow.

D. Stem cells can be harvested by destroying human embryos.

Question 7 .

Which of the following is an example of a beneficial application of transgenic organisms?

A. using DNA fingerprinting techniques to identify a person

B. cloning human stem cells to produce human tissue

C. inserting genes for disease resistance into a tomato plant's genome

D. sequencing DNA to identify gene mutations that may cause disease

Question 8 .

Many scientists believe that stem cells might be useful for treating certain human diseases in the future. Stem cells are cells that

A. are modified viruses that can be used to transfer genetic information.

B. have the potential to differentiate into various specialized cell types.

C. are very small and can only be found in plants.

D. lack the ability to undergo cell division through mitosis.

Question 9 .

Ethics focuses on moral issues. Using ethics, people attempt to determine what is good and bad or what is right and wrong.

Which of the following questions involves ethical considerations?

A. Should scientists be permitted to genetically modify plants?

B. Should people be permitted to have in vitro fertilization?

C. Should unborn children be tested in the womb for genetic disorders?

D. all of these

Insulin is a hormone that regulates blood sugar levels in the human body. Scientists can synthesize a form of insulin by inserting the human insulin gene into bacterial plasmids. Scientists can then harvest the insulin produced by the bacteria. Which of the following statements best describes this process?

A. Genetic engineering can create transgenic organisms that benefit society.

B. Genetic cloning can create organisms that benefit society.

C. Genetic cloning can create organisms that pose a risk to society.

D. Genetic engineering can create transgenic organisms that pose a risk to society.

Question 11 .

Directions: Select each correct answer.

The Human Genome Project has determined the sequence of base pairs in the entire human genome. How does this project directly impact our understanding of genetic diseases?

It makes it easier to find the genes causing diseases.

It provides a cure for all diseases.

It explains the cause of all genetic diseases.

Question 12 .

Advances in biotechnology, especially regarding genetic testing and gene therapy, now allow for the screening and possible treatment of many genetic disorders. During gene therapy, for example, specific gene sequences are inserted into an individual's cells and tissues to replace a defective or mutant allele.

What have scientists found to be the most efficient and effective way to insert new sequences into an individual?

A. Scientists use viruses to insert specific gene sequences.

B. Scientists inject DNA strands into cells using a syringe.

C. Scientists have created genetically altered foods that release DNA during digestion.

D. Scientists irradiate genes so that they can be absorbed through the skin.

The diagram below shows an example of how DNA fragments can be separated using gel electrophoresis. DNA fragments are loaded into the wells at the top of the diagram.

Which of the following statements correctly describes the DNA fragments?

A. Lane 2 contains the longest DNA fragment.

B. Lane 4 contains the slowest moving DNA fragment.

C. Lane 1 contains the most DNA fragments.

D. Lane 3 contains the shortest DNA fragments.

Question 14 .

Which of the following best describes bacterial transformation?

A. converting one species of bacteria into another species

B. changing the shape of bacteria

C. introducing foreign DNA into bacteria

D. creating a replica of bacterial DNA

Question 15 .

Many scientists believe that stem cell research will one day lead to new treatments for diseases, but some people have ethical concerns about this research. Which of the following characteristics of stem cell research is the most likely source of ethical controversy?

A. Stem cells are often extracted from human embryos.

B. Stem cell research requires specialized equipment.

C. Stem cells can replace damaged cells with healthy cells.

D. Stem cells naturally produce many different cell types.

The diagram below shows a DNA fingerprint from a crime scene, as well as the DNA fingerprints of four suspects.

Based on the DNA fingerprints, which suspect most likely committed the crime?

A. suspect 3

B. suspect 1

C. suspect 2

D. suspect 4

Question 17 .

In the 1920's, a woman by the name of Anna Anderson claimed to be the Grand Duchess Anastasia, the youngest daughter of Tsar Nicholas II. However, DNA testing confirmed that she was not who she claimed to be. Which of the following uses of biotechnology does this example best demonstrate?

A. Biotechnology allows for determining the degree of relatedness among individuals.

B. Biotechnology allows for the screening and possible treatment of genetic disorders.

C. Biotechnology allows for the improved varieties of plants, animals, and medicines.

D. Biotechnology allows for criminals to be captured through forensic testing.

Question 18 .

What type of research is only possible because of the completion of the Human Genome Project?

A. determining whether an individual carries the genes for a particular genetic condition

B. determining the relatedness of species by comparing gene sequences

C. comparing DNA sequences between species so that they can be correctly classified

D. selectively breeding traits that are the most beneficial to society

Stem cells are cells that are undifferentiated, and therefore have the potential to differentiate into a wide variety of specialized cell types.

How might stem cells most likely be used in the future to treat human disease?

A. Stem cells could be used to prevent genetic mutations that occur at birth.

B. Stem cells could be used as vectors to insert genetic information into human DNA.

C. Stem cells could be modified to produce chemicals that kill bacteria and viruses.

D. Stem cells could potentially be used as a source of renewable healthy cells and tissues.

Question 20 .

Biotechnology has given humans the ability to see what a person's genes will be like before they are even born. Why is choosing whether or not to test an unborn child for a genetic disease an ethical decision?

A. Genes carry the information that determines what color eyes the child will have.

B. Genetic testing may lead to difficult questions about what is best for the unborn child.

C. Some people don't like doing medical tests.

D. There are no treatments available for genetic diseases.

1. B

2. D

3. A

4. C

5. C

6. D

7. C

8. B

9. D

10. A

11. --

12. A

13. A

14. C

15. A

16. C

17. A

18. A

19. D

20. B