JMHS Biology Essential Concepts

John Marshall LIFE SCIENCE JMHS Biology Essential Concepts

ThESE PAGES HOLD THE TOOLS NEEDED TO SUCCEED IN BIOLOGY. HOWEVER, YOU WILL BE EXPECTED TO APPLY THESE TOOLS NOT JUST Carry them around. John Marshall Biology Essential Concepts

I. History and Nature of Science

1. A law is a generalization on how some aspect of the natural world behaves under stated circumstances.

2. A theory is defined as a solid explanation of some aspect of the natural world that can incorporate facts, laws, and tested hypotheses. 3. The process of collecting data by taking pictures, writing down what you see, and even taking measurements of what you see is called an observation. When conclusions are drawn by using what you know and what you see, you have developed an inference.

4. The scientific method is a series of steps used to help scientists solve problems.(Identify the Problem, Hypothesis, Experiment, Observation (Data Analysis), and Conclusion)(PHEOC).

Scientists use peer review to discuss and validate results and check for bias.

 When a testable statement about the natural world has been created it is called a hypothesis. (educated guess)  In a controlled experiment there are two test groups. There is an experimental

group and a control group.

 The control (the normal situation) is used to compare against the experimental data collected.

 The independent variable (manipulated variable) is what is changed in an experiment.

 The dependent variable (respondent variable) is what responds to what is changed in an experiment.

 Data collected in an experiment can come in two forms. The first type of data is called quantitative data (number) and revolves around exact objective measurements. These measurements use a measurement tool. The second type of data that can be collected is called qualitative data (description). This type of data is more subjective and less precise and is based on the scientist’s personal observations.

 Data needs to be viewed for sources of error.

5. The metric system is a measurement system that allows all scientists to use common units, which include but are not limited to meters, liters, and grams. The prefixes of the metric system include but are not limited to kilo, hecto, deka, base, deci, centi, and milli. (Other metric units include Celsius, Pascals, Sieverts and Newtons).

6. Graphing is a fundamental part of sharing information/data in a visual way. Pie, Chart,

Line, Bar, Histogram, Pictograph are all types of graphic organizers. Each graph is used for a

specific type of data illustration/interpretation and has its own format. Components of a

good graph are; title, labeled axis, a legend and appropriate units of measure.

7. Anything that causes an organism to react to their environment is called a stimulus (cause). When the organism actually reacts with its stimulus that reaction is termed a response (effect). This helps maintain homeostasis, which is how organisms maintain an internal environment which can be different from what is surrounding them. 8. Characteristics of Life is a set of criteria that allow scientists to determine if something should be considered living or not. They include the following set of criteria:

1) is made of cells 4) has ability to reproduce 7) maintains balance (homeostasis)

2) displays organization 5) has ability to respond to stimulus

3) grows and develops 6) has ability to use energy 8) has ability to adapt/evolve over time Life Science (Ecology Emphasis)

9. Ecology is the study of the relationships of organisms (biotic) with one another and with the environment (abiotic).

10. The levels of organization for ecology are as follows

 Biosphere is the layer around Earth where all living things are located.  Biome is a large area of land or water with similar climate, plants, and animals. The following are some examples of biomes: tropical rainforest, desert, grasslands, deciduous forest, and coniferous forest.  Ecosystem is a community of living (biotic) organisms interacting with the non-living (abiotic) environment.  Community is made of many different populations of organisms interacting with their environment.  Populations are the total count of one species within a given area.  Species is classified as a group of organisms that can successfully mate and produce fertile offspring.

11. Population growth is slowed when an organism runs out of space, food, water, or shelter. Each of these is called a limiting factor. 12. The area in which an organism lives is called a habitat. An example of a habitat is a rabbit living in a log. The job of an organism within its habitat is called its niche. An example of a niche would be a bird eating seeds on the ground.

13. All organisms do not get their energy to live the same way. Organisms that make their own food are called autotrophs. Most organisms that make their own food use the process of photosynthesis. Organisms that can’t make their own food are considered heterotrophs.

14. Once limiting factors slow population growth, the population growth will eventually stop and become balanced. This occurs when the birth rate equals the mortality rate. The population is said to have reached its carrying capacity when this balance is reached. The population graph that shows carrying capacity is considered a logistical growth curve and is “S” shaped. Larger animals usually display this type of growth. Exponential growth occurs when populations double at a very fast rate. Organisms that display this type of growth are small and usually seasonal, such as bugs, bacteria, and small rodents. A graph that shows exponential growth is considered “J” Shape. 15. Energy is transferred in an ecosystem through a food chain starting with the sun releasing its energy to plants (producers). Then primary consumers (herbivores) eat the plants taking a small amount of the plants’ energy. Secondary consumers (carnivores and omnivores) then eat the primary consumers, gaining a small amount of their energy. When food chains overlap in an ecosystem, food webs are created.

16. Populations can change when members of its population leave the area; this is called emigration. New members can also enter a population, this is called immigration. 17. Symbiosis can occur when different species live together in a close association; this includes parasitism, commensalisms, mutualism, and predator/prey relationships.  Parasitism is a relationship when one organism benefits (parasite) and the other is harmed (host).  Commensalism is a relationship when one organism benefits and the other is not affected.  Mutualism is a relationship when both organisms benefit.  Predator/Prey is a relationship when one organism eats (predator) another organism (prey). 18. Biogeochemical Cycles (also known as matter + energy cycles) allow us to visualize how nutrients are recycled within our environment. (ex. Water Cycle, Carbon Oxygen Cycle, Nitrogen Cycle, and the Phosphorous Cycle) 19. The risks associated with environmental factors and personal decisions need to be analyzed to know the effect on personal and community health. These can be labeled as either point or non point sources.  Water quality  Air quality  Soil quality

II. Life Science (Emphasis Biochemistry) 20. The smallest particle of matter is the atom. The atom contains protons and neutrons within the nucleus. The atom also has small particles called electrons that orbit the nucleus. Atoms that have the same number of protons and have different number of neutrons are called isotopes. When matter is made from the same atoms it is called an element. Common biological elements = C-carbon, O-oxygen, H- hydrogen, N-nitrogen, P-phosphorous, S-sulfur 21. Compounds are created when more than one atom bond together. When compounds join together using covalent bonds they are called molecules. Chemical bonding occurs when atoms join together. When the atoms share electrons, covalent bonds are created. These are one of the strongest types of bonds. When atoms join together by transferring electrons to one another, they become attached due to ionic bonds. When atoms lose or gain electrons they are termed ions. A positive ion is called a cation, a negative ion is called an anion. 22. A hydrogen bond is a molecular force that is created when two polar molecules get close to one another, creating a very weak bond. This is a type of Van der Wals Force. Polar Molecules are slightly positive and negative on opposite sides of the molecule. 23. A macromolecule is an extremely large molecule. Macromolecules include proteins, lipids (fats), nucleic acids, and carbohydrates.  Proteins are macromolecules that are building blocks for our bodies. They are created on the ribosomes of our cells. They are built by linking amino acids together.  A lipid is a macromolecule that is used in our body to store energy and create hormones. Lipids are built using two subunits. They are fatty acids and glycerol.  Nucleic acids are macromolecules used in our body to create a genetic blueprint to control the cells functions. This material is made by linking nucleotides together. Nucleic acids help create D.N.A. and R.N.A..  Carbohydrates are macromolecules used to create quick sources of energy for our bodies. A simple sugar called glucose is the building block for this macromolecule. Carbohydrates have two forms: monosaccharides (simple sugars like glucose) and polysaccharides (complex carbohydrates built from simple sugars). Polysaccharides are found in animals as glycogen and are found in plants as starch.

24. When macromolecule subunits are joined together, a water molecule must be taken out. When this occurs it is called dehydration synthesis. When macromolecules are taken apart during digestion, a water molecule must be added to break them apart. This process is called hydrolysis. 25. Enzymes are proteins that speed up chemical reactions. (examples: polymerase, helicase, ligase, pepsin, and amylase). They do this by lowering the activation energy of a chemical reaction. Enzymes are not used or consumed during a reaction but only used to “help along” the reaction. The activation energy is the energy it takes to get a chemical reaction to start. Since enzymes aid in speeding up chemical reactions they are also called catalysts. Enzymes speed up chemical reactions by allowing substrates to attach to them, allowing them to react at a faster rate. When writing out a chemical equation there are two sides to the equation. The left side of the equation is called the reactants or the ingredients for the reaction to take place. The right side of the equation is called the products. This is what is produced from the reactants. 26. There are two different types of chemical reactions, endothermic and exothermic. Exothermic reactions are those that release energy as they occur. Endothermic reactions absorb energy as they occur. 27. Water is important to life for multiple reasons;  Water exhibits cohesion and adhesion. When similar polar molecules are attracted, it is called cohesion. When molecules that are not similar attract, it is called adhesion.  Water has a high specific heat (it takes a lot of energy to change the temperature water).  Water is a good solvent; many organic compounds dissolve in water. Solvent is the name given to something doing the dissolving, Solute is the name given to something being dissolved.  The pH scale, which stands for the potential of hydrogen ions, is a scale that measures the concentration of hydrogen ions (H+) or hydroxyl ions (OH-) in a solution. The scale goes from 0 to 14. The number seven is neutral, meaning the solution has the same number of hydrogen and hydroxyl ions. Water is considered to be neutral. The more acidic a solution is, the more hydrogen ions (H+) it has. The more basic a solution is, the less hydrogen ions (H+) it has.

III. Life Science (Cell Biology Emphasis)

28. The cell theory, which was developed by Rudolph Virchow, Matthias Schleiden and Theodor Schwann, states the following:  all living things are made up of one or more cells  cells are the basic units of life  all cells can only come from other living cells

29. A prokaryote is the simplest of all living cells. The prokaryote contains no nucleus within its cell. Its only genetic information is a circular strand of DNA. Bacteria make up all of the prokaryotes. The prokaryotes can be broken up into two kingdoms: the archeobacteria and the eubacteria. A eukaryote is a more complex cell that has many organelles which include a true nucleus. Eukaryotic cells help create four different kingdoms, the protist, fungi, plant, and animal kingdoms.

30. Cells contain small organ like structures that carry out many important functions for the cell. These small structures are called organelles. The following are some of the more important organelles in a eukaryote:  The nucleus is the control center of the cell. The nucleus is surrounded by a nuclear membrane that protects the DNA and nucleolus that is with the nucleus. This organelle is found in all eukaryotes.

 The cell membrane surrounds all cells. It allows material to be passed in and out of the cell. It is made by a double layer of phospholipids with protein channels extending through both layers..  The cytoplasm is a clear jelly like fluid that is found within all cells. This liquid contains all the organelles found within the cell, but also allows material to pass through it.  The cell wall is a stiff protective coat found on both eukaryotic and prokaryotic  cells. The cell wall can be made of things like chitin and cellulose. The cell wall is not present in animal cells.

 The mitochondria is an organelle that creates energy for both animal and plant cells in the form of ATP. The mitochondria is the site where respiration occurs.  The endoplasmic reticulum is an organelle that is made of networked canals. This organelle’s main job is to transport proteins to the Golgi Body.  Proteins are built on an organelle that is called a ribosome. Ribosomes can be found in prokaryotes and eukaryotes. They are made primarily out of ribosomal RNA.

 Golgi body looks like a bunch of flattened sacs in a cell. The Golgi body’s main job is to package and distribute molecules (proteins) that are created in the cell.

 Lysosomes are small vesicles that contain powerful enzymes that digest old cell parts and foreign material that makes its way into the cell.  Vacuoles are used to store water and waste. In a plant cell it is called the central vacuole and is very large so that it can store a good amount of water. In animal cells they are much smaller, storing mostly waste.  Chloroplasts are organelles that are found only in plant cells. Their main job is to collect sunlight for the process of photosynthesis. These organelles have their own DNA and are thought to have once been symbiotic bacteria.  Centrioles are found only in protist and animal cells. Their job is to aid in cell reproduction.  Cytoskeleton is a support structure in the cell.

31. Passive transport; diffusion occurs when any particle moves from an area of high concentration to an area of low concentration. Osmosis is a special type of diffusion where water moves across a semi-permeable membrane from a high to low concentration. Facilitated Diffusion is nothing more than diffusion with the aid of a protein channel.  Hypertonic = the solute concentration is higher than that on the other side of a membrane.  Hypotonic = the solute concentration is lower than that on the other side of a membrane.  Isotonic = the solute concentration is the same on both sides of a membrane.

32. Active transport occurs when material has to pass into or out of a cell from a low to high concentration. This requires energy from the cell. (Examples include the following: endocytosis, exocytosis, sodium/potassium pump, and proton pump). Endocytosis is a type of bulk transport that allows large molecules to enter a cell. Exocytosis is another type of bulk transport that allows large molecules to exit a cell. 33. Photosynthesis is a process used by plants to create sugar (glucose). This then becomes the plant’s food. This process occurs in the chloroplast of the plants cell. (Sunlight, water, and carbon dioxide are used to produce sugar, water, and oxygen). 34. Cellular Respiration is a process used by both plant and animal cells to produce energy in the form of adenosine tri-phosphate (ATP). This process occurs in the mitochondria of the cell. Respiration uses sugar and oxygen to create energy, and release water and carbon dioxide.

35. Cell Cycle is a series of steps in the life of a cell. These include Interphase (Growth1, Synthesis S, Growth2), Mitosis or Meiosis (see below), and Cytokinesis. (Cytokinesis is the division of the cytoplasm creating new cells).

36. Mitosis (Prophase, Metaphase, Anaphase, Telophase) is a process used by eukaryotes to allow them to grow and heal. Through this process one body cell containing a diploid set of chromosomes will separate and create two new body cells with a diploid set of chromosomes. Body cells include any cell besides gametes.

37. Cancer is the unregulated growth of cells.

38. Meiosis is a process that creates gametes (sex cells). Gametes contain a haploid number of chromosomes which is half the number of the original cell. This occurs so that half the number of chromosomes from the male sperm cell can fertilize the egg cell of a female, which contains a half the number of chromosomes. After fertilization occurs, a zygote is created (first cell of life). (Prophase I, Metaphase I, Anaphase I, Telophase I, Prophase II, Metaphase II, Anaphase II, Telophase II)

39. During prophase I of meiosis a key event that provides genetic diversity is crossing over.

40. There are five levels of organization for multi-celled organisms:  Cells  Tissue (cells working together with a common function)  Organs (made of tissues that have common function)  Organ Systems (made of organs working together)  Organism (made from organ systems working together) IV. Life Science (Mendelian Genetics Emphasis) 41. The passing of traits from one generation to the next is called heredity. 42. In 1860 an Austrian monk named Gregor Mendel was the first documented person to study the genetic traits are inherited. 43. Allele is an alternate form of a gene. It can be dominate or recessive. Examples include T = Tall (dominate), t = short (recessive).

44. The genotype is the gene combination that determines what trait will be expressed on an organism. Genotype of an organism for a specific trait can either be homozygous (purebred), which means the gene combination is the same, or it can be heterozygous (hybrid), which means the gene combination is mixed. The phenotype is the expressed trait that can actually be seen on an organism. This is determined by the genotype for that specific trait. 45. The dominant gene is the strong form of a gene. It is expressed in both homozygous and heterozygous situations. The recessive gene is the weaker form of the gene. It is not expressed unless it is homozygous recessive. When genes for a specific trait are heterozygous and a mixture occurs which creates a phenotype that blends the two genes together, incomplete dominance has occurred. (Example White flowers crossed with Red flowers create pink flowers)When a specific trait has more than one dominant gene, co-dominance can occur. When both dominant genes combine, both genes are expressed individually. This occurs with our blood type. The dominant genes are the A and B blood type. The recessive is the O blood type. Sex-linked traits are those that are linked to the 23rd pair of chromosomes. This pair of chromosomes determines gender. Chromosome pairs 1-22 would instead be considered autosomes. These chromosome pairs have nothing to do with gender.

46. Punnett Square is a tool used to determine the possible genotypes of offspring.

47. Two laws were developed by Gregor Mendel. a. The Law of Segregation states that only one gene for a specific trait can be carried in a gamete, and gametes combine randomly, forming offspring. b. The Law of Independent Assortment states that genes on different chromosomes are inherited independently of one another. V. Life Science (Molecular Genetics Emphasis) 48. James Watson and Francis Crick discovered the structure of Deoxyribonucleic acid (DNA) on February 28th, 1953. They received the Nobel Prize in 1962 with another scientist named Maurice Wilkins. Their discovery would not have occurred without the help of scientist Rosalind Franklin who was taking X-ray diffraction pictures of DNA at the time of their discovery. She later died of cancer at the age of 37 and before they awarded the Nobel Prize. 49. DNA, also known as deoxyribonucleic acid, is a genetic material that forms genes and creates the chromosomes that make us who we are. DNA is made from sugar (deoxyribose), phosphate, and nitrogen bases. These three parts make up a structure called a Nucleotide, which is the building block of DNA. The nitrogen bases are named as follows: Adenine (A), Thymine (T), Cytosine (C), and Guanine (G). These nitrogen bases pair together in the following pairs- A-T and C-G. Genes are segments of DNA that determine our traits. Chromosomes are long strands of DNA made up of many genes that determine our traits. Humans have 23 pairs located in the nucleus of our cells. When mistakes are made during the replication of DNA, mutations can occur. Mutations can cause new phenotypes to occur by either adding, deleting, or recombining the nucleotides which in turn may call for different amino acids. These mutations can be helpful, harmful, or can cause nothing to happen. 50. If a mutation changes the workings of the cell cycle, cancer may result.

51. A pedigree is used to determine patterns in the way traits are expressed over generations in a family tree. 52. DNA replication is the process by which DNA copies itself. This occurs during both mitosis and meiosis. This process occurs during the “S” phase of the cell cycle. 53. Central Dogma of Biology: When DNA splits apart and allows Ribonucleic acid to form in the nucleus of a cell, transcription is taking place. RNA is similar to DNA but is only one strand and contains the nitrogen base uracil (in place of thymine). When the single strand of mRNA lands on a ribosome, it is read. Then tRNA molecules bring specific amino acids depending on the mRNA genetic sequence. Matches are made between the mRNA (codon) and tRNA (anticodon) to determine the amino acid sequence. This process that eventually builds proteins is called translation.

54. Karyotype is a person’s visual display of all 23 pairs of chromosomes. Chromosome pairs 1- 22 are called autosomes. The 23rd pair is called the sex chromosomes.

VI. Life Science (History of Life and Evolution)

55. When living organism change over time, evolution has taken place. When living organisms live or die within their ecosystem based upon their effective or ineffective adaptations, natural selection is said to have taken place. The organisms that live on are able to pass their genetics on to the next generation, while the organisms that die are not. Natural selection is a mechanism that allows evolution to take place. Natural Selection follows these 4 principles:  Variation – a range of traits within the gene pool.  Heritability – traits can be passed on from parents to offspring.  Overproduction – more offspring are produced than can survive.  Reproductive Advantage – some traits allow an organism to find more success in producing offspring. 56. Artificial Selection occurs when humans choose what traits are allowed to be passed on to the next generation. An example of this can include breeding dogs for specific breeds.

57. Charles Darwin developed a theory of evolution based on natural selection which he stated as “Survival of the Fittest.” He was a naturalist on the HMS Beagle. 58. Evidence for Evolution include the following:  Fossil Record  Homologous Structures  Embryological Development (Embryo Structure)  Biochemical Similarities (DNA structure) 59. Anatomically similar structures inherited from a common ancestor are called homologous structures (ex. Common mammal structure). Not all anatomically similar features are evidence of common ancestry. Analogous structures (ex. Bird wing vs. Insect wing) have the same function and may even have a basic structure that is similar. However, they do not come from a common ancestry. 60. The Hardy-Weinberg principle states that unless there is pressure put on the various allele frequencies, evolution will not occur. However, in most cases there is pressure from the environment to choose which allele frequencies will be successful (If it ain’t broke, don’t fix it). 61. Any change in the allele frequencies in a population that is due to chance is called genetic drift. The founder effect is an extreme example of genetic drift. This can occur when a small sample of the population settles away from the larger population. Another example of genetic drift is the bottleneck; this occurs when a population declines to a very low level and then rebounds. The remaining gene pool is limited to what is left after the bottleneck. 62. Gene flow occurs when organisms move between populations or migrate, increasing the size of the gene pool through sexual reproduction. 63. The Hardy-Weinberg principle requires that all individuals in a population be equally adapted to their environment and thus contribute equally to the next generation. Since this never happens, natural selection is always at work. The following are different types of natural selection at work:

 Stabilizing selection: This is the most common type of natural selection, in which the genotypes that code for extreme phenotypes are eliminated by the environment.  Directional selection: This occurs when one extreme of the gene pool is chosen over the other extreme, and the gene pool will shift to one side or the other.  Disruptive selection: This type of natural selection chooses against the middle genotypes. The extremes genotypes are successful in this example.

64. Reproductive Isolating mechanisms can stop gene flow from occurring which in the end can create new species. There are two basic types of isolating mechanisms: they are called pre- zygotic and post-zygotic isolating mechanisms. Pre-zygotic mechanisms stop the sperm and egg from ever meeting. Post-zygotic mechanisms help stop the new zygote from ever being fertile.

65. When a population diverges and becomes reproductively isolated, speciation will occur. These are the two types of speciation:

 Allopatric speciation: Occurs when a population is divided by a geographic barrier and then is reproductively isolated, creating 2 new species.

 Sympatric speciation: Occurs when a population is not divided by a physical barrier.

66. Co-evolution is a term that describes the long term evolutionary adjustments that are made between two species interacting with one another. When two unrelated species develop similar structures (analogous structures) due to similar environments, it is said that convergent evolution has taken place. (Example wings of birds and insects)When one population of a given species becomes separated due to newly created natural barriers, then each population adapts to its different environments over time. Eventually these populations become so different that two new species are created. When this occurs, it is called divergent evolution.

67. Adaptive Radiation occurs when a species discovers a new habitat that contains many niches that need to be filled. The original population quickly radiates (moves) into these new areas and begins to diverge into new species.

VII. Life Science (Classification Emphasis) 68. Taxonomy is the science of classifying living organisms. All living organisms are broken into Taxonomic categories. The most inclusive would be the 3 Major Domains (Archaea, Eubacteria, and Eukarya). The next most inclusive category is the kingdoms. They are as follows: Animal, Plant, Fungi, Protist, Bacteria and Archaea.

69. Cladistics is a method that classifies organisms according to the order that they diverged from a common ancestor. Cladograms and phylogenetic trees are visual diagrams that show how organisms have diverged from their ancestors.

VIII. Life Science ( Bacteria and Virus Emphasis)

70. Bacteria are prokaryotes that are microscopic, unicellular, and are found everywhere. There are two major types of bacteria. There are the archaea which are considered to be our most primitive ancestors because of their similar proteins with the cytoplasm. The other type of bacteria is called eubacteria. These bacteria are found with 3 basic shapes. The shapes are as follows: rod shaped (bacilli), spherical (cocci), and spiral (spirillium). 71. Reproduction for prokaryotes can occur in two different ways, which include binary fission and conjugation. Binary Fission is the division of cells into two genetically identical cells. Conjugation can occur when the pili of two bacteria connect and swap their genetic information. 72. Germ Theory – developed by Louis Pasteur and many other scientists states that all infectious disorders are caused by microorganisms. This was later supported by Robert Koch.

73. Prokaryote structure (Diagram)

74. Viruses are non-living structures that depend on their host to replicate. They are microscopic and are not made of cells. They are made of a protein coat (capsid) and some genetic material inside being either DNA or RNA.

75. Virus reproductive cycles include the Lytic Cycle and the Lysogenic Cycles. The lytic cycle, once set in motion, immediately begins to make virus parts by injecting its genetic material into the DNA of the host cell and forcing it to make the parts. When all the virus parts are created and assembled, they break the cell open. The lysogenic cycle occurs when the virus injects it genetic material into the host’s DNA and then goes dormant. This allows the host cell to go through mitosis and make new cells. Each of those new cells is infected with the virus’s genetic material.

76. Prions are misfolded proteins that can be transmitted between individuals and create illness.

77. The Immune System produces antibodies (chemicals the body produces) to fight antigens (like a foreign substance that is introduced into the body which can cause an immune system response). Vaccines introduce antigens (like weakened or destroyed viruses) so the body will produce antibodies (in preparation for the real thing). Autoimmune disease occur when the body attacks its own cells. Allergic reactions are caused by the body’s immune response to usually harmless environmental substances. IX. Life Science (Emphasis on Plants)

78. Plants are autotrophic eukaryotic organisms made of many cells. They use photosynthesis to make their own food using the sun’s energy. Once the food is made, it is usually stored in the roots of the plants. Cellular respiration can also be used by a plant to burn the glucose (sugar) it produced into energy in the form of ATP.

79. Non-vascular plants do not have any system for transferring water. They need to stay close to a water source because of this. Examples include moss and liverworts.

80. Vascular plants have a defined system to carry both food and water. Xylem tissue carries the water from the roots to the leaves. The phloem tissue is in charge of moving the sugar made in the leaves to store in the roots. Vascular plants are broken into three groups: Ferns, Angiosperms and Gymnosperms.

81. The stoma is a special opening that allows gases like carbon dioxide, water vapor, and oxygen to pass in and out of the leaf of a plant. This opening is found on the underside of most leaves. This reduces the amount of evaporation that can take place. Guard cells are specialized cells that control the opening and closing of the stoma in a plant cell.

82. Tropic Responses are plant growth responses to an external stimulus. Examples include:  Gravitropism is a response to gravity. Roots down, stems up.  Phototropism is a response to light. Plants growing towards the light.

83. Like animals, plants also create hormones which are used to control metabolisms within the organism. Examples of plant hormones include Auxins, Gibberellins, and Ethylene.

X. Life Science (Emphasis on Animals)

84. Animals are multicellular, eukaryotic organisms that must go out and find food to eat. They are found in almost any habitat. Most are able to move at least in one part of their life cycle. They use cellular respiration to create energy in the form of ATP from the food they eat.

85. Animals are classified by using physiological traits. One of the biggest divisions is whether or not an animal has a backbone (vertebrata).  Invertebrates include: Sponges Cnidaria Nematode Platyhelminthes Annilida Mollusks Arthropod Echinoderm  Vertebrates are broken down into multiple classes and are called: Agnatha Chondrichthyes Osteichthyes Amphibia Reptilia Aves Mammalia

86. The skeletal system of animals can either be inside the body or outside the body. An endoskeleton is a skeletal system that is inside the body of an organism. An exoskeleton is a skeletal system that encases a body in a hard shell like most insects. 87. Radial symmetry is the regular arrangement of parts around a central axis. If a line is drawn from any direction through the center of an organism, each side will be a mirror image of the other. Bilateral symmetry occurs when the left and right side of an organism are close to mirror images of each other. Asymmetry occurs when an organism has no symmetry at all.

88. Internal Fertilization occurs when the sperm and egg meet inside of the animal’s body. External Fertilization occurs when the sperm and egg meet outside of the animal’s body.

89. When a zygote is created after fertilization of egg and sperm, mitosis takes place creating a fluid filled sack of cells called a blastula. In the blastula the total number of cells increases every time mitosis takes place, but the amount of cytoplasm stays the same. Eventually the blastula folds in on itself creating almost a double bubble called a gastrula. This gastrula will eventually lead to the creation of the following three layers: ectoderm (outside layer) develops into nervous tissue and skin, mesoderm (middle layer) may develop into specialized body systems in more highly developed organisms, and the endoderm (inside layer), which will develop into the organisms digestive system.

90. Depending on which way an organism develops, animals can have one of 3 different body plans: acoelomate, psuedocoelomate, and coelomate.

XI. Life Science (Emphasis Human Body Systems)

91. Organisms use organ systems to maintain homeostasis. The body uses negative feedback to regulate body temperature, pH, heart rate, breathing etc. (for example- sweating when hot, shivering when cold)

92. The nervous system coordinates all the activities of the body. The principle components of the system are nerves, sense organs, brain, and the spinal cord. The nervous system is made of two subsystems, which are the central and the peripheral nervous system.  A neuron is a single nerve cell made of a cell body, dendrites, and an axon.  A synapse is the space that is found in between nerve cells. Chemicals called neurotransmitters carry signals from one nerve cell to the next.  The central nervous system is composed of the brain and spinal cord. The peripheral nervous system is composed of the motor and sensory system.

93. The Circulatory system transports blood to deliver important substances, such as oxygen, to cells and to remove wastes, such as carbon dioxide.  Blood is made of a liquid medium called plasma, which carries red blood cells, white blood cells, and platelets.  Blood flows through tubes, which are organized and named based on their function. They include arteries, veins and capillaries.  The major organ of the circulatory system is the heart. It is comprised of four chambers: 2 ventricles and 2 atria. 94. The Respiratory system is where the exchange of CO2 and O2 (carbon dioxide and oxygen gasses) takes place.  The lungs are the major organ in the respiratory system and they are pumped by the action of the diaphragm contracting and relaxing.  Gas exchange happens in small structures called alveoli, which are surrounded by capillaries. 95. The Digestive system breaks down food so nutrients can be absorbed by the body.

 The major structures of the digestive system are the Mouth, Esophagus, Stomach, Small intestine, and Large intestine.  The digestive system uses both mechanical and chemical means to break down food. 96. The Reproductive system key terms:

 Male - Vas deferens, Urethra, Penis, Testis, Scrotum, Epididymis, Prostate, Sperm, Semen  Female - Ovary, Oviduct, Uterus, Cervix, Vagina, Egg, Follicle, Oocytes, Menstrual  Male Hormones - Testosterone, Gonadotropin-releasing hormone (GnRH), Follicle- stimulating hormone (FSH), and Luteinizing hormone (LH)  Female Hormones - Follicle-stimulating hormone (FSH), Luteinizing hormone (LH), Estrogen, and Progesterone  Development - zygote, morula, blastocyst, embryo, fetus, amniotic fluid, placenta, ultrasound, and amniocentesis

97. The Immune system: The immune system is comprised of the following parts; lymph system, circulatory system, white blood cells (which include T and B white blood cells), skin, antigens, and antibodies. These parts all use the following lines of defense to prevent infections.

 First line of defense Skin, Mucus, Saliva, Stomach Acid, Cilia

 Second line of defense Histamines, Interferon, White blood cells

 Third line of defense Antibodies