Chapter 3: Cells KEY .59 Points

Chapter 3: Cells KEY….59 points Focus on Wellness…DID YOU KNOW? (Pages 48 and 70) 1 point each = 2 points 1. What are phytochemicals? _plant chemicals thought to be beneficial in offsetting cancer and heart disease risks______2. What are some dietary changes you could make that would increase your intake of helpful phytochemicals? _consume more plant foods; reduce intake of just meat-and-potato type of diets______I. A Generalized View of the Cell 1 point each = 3 points OBJ: Name and describe the three main parts of a cell. A.1. _plasma membrane: flexible outer layer separating cell’s internal environment from its external environment; regulates what flows in and out______A.2. _cytoplasm: all cellular content inside plasma membrane; excludes nucleus______A.3. _nucleus: control center because it contains genes that have code for all cellular activities and structures______CHECKPOINT: 2 points ; 2/3 point each 1. What are the general functions of the three main parts of a cell? _plasma: regulate what goes in and out______cytoplasm: contains cytosol with dissolved solutes and suspended particles for cell use; suspends organelles within the cell______nucleus: control center of the cell; directs all activities and structure building______II. The Plasma Membrane ¼ point each = 4 ¾ points OBJ: Describe the structure and functions of the plasma membrane.

1. Explain the functions of the plasma membrane. _sturdy flexible barrier; controls what enters and leaves; enables cells to recognize other cells as same or foreign______2. Describe the structure of the plasma membrane. _phospholipids, cholesterol, and glycoproteins 3. Name and describe the two types of glycoproteins found in the plasma membrane. _ two types: integral proteins- extend through plasma membrane, and peripheral proteins- loosely attached to interior and exterior of plasma membrane______4. Selective permeability: Lipid bilayer is permeable to: A.1.a. _water______A.1.b. _most lipid-soluble molecules_ Examples: _fatty acids______fat-soluble vitamins______steroids______oxygen______carbon dioxide______Lipid bilayer is not permeable to: a. _ions______b. _charged particles or polar molecules_ Examples: _glucose______amino acids______Channels are formed by _integral proteins______Transporters change shape as they _move substances from one side to other______5. Recognition: a. Receptors recognize and bind to specific molecules Examples: _hormones______b. Enzymes _speed up chemical reactions______c. Cell identity markers _identify same cells (during tissue formation) or foreign cells (danger)______11 ¾ points possible III. Transport Across the Plasma Membrane ¼ point each = 2 ¼ points OBJ: Describe the processes that transport substances across the plasma membrane. 1. Fluids- _~60_% of the average body a. Intracellular fluid- _ICF_- _in cytosol_ b. Extracellular fluid- _ECF______(1) _interstitial_- _in between cells of tissues______(2) _plasma___- _in blood vessels______

2 (3) _lymph____- _in lymphatic vessels______2. Concentration a. _amount of solutes in solution______b. Concentration Gradient- _difference in concentration between two areas______3. Practice: ½ point

Will move high to low; water; passive transport known as osmosis until equilibrium is reached (isotonic) A. Passive Processes 1. Diffusion: The Principle ¼ point each = 1 point a. _high to low; no energy required______b. Diffusion defined: -Substance moves due to kinetic energy -Movement from high concentration to low concentration -Movement of more molecules in one direction is called net diffusion -Movement ‘down the concentration gradient’ -Continues until equilibrium is reached SIMPLE DIFFUSION _movement of materials through bilayer; important exchange of

gases; absorption of liquids and release of some wastes: O2, CO2, N2, fatty acids, steroids, fat-soluble vitamins [A, D, E, and K], glycerol,

small alcohols, NH3, H2O, and Urea [polar]______move materials through often gated channels (integral proteins): K+, Cl-, Na+, and Ca+__ FACILITATED DIFFUSION _move through integral proteins; substance binds to specific transporters [these change shape]: glucose, fructose, galactose, urea, some vitamins______Figure 3.3, page 51: 1 point

3 1. How does simple diffusion differ from facilitated diffusion? _simple substances cross membrane through lipid bilayer; facilitated ion channels or carriers involved______2. Osmosis ¼ point each = ¾ point a. _movement of water across a selectively permeable membrane

from an area of high concentration of H2O to area of low

concentration of H2O, no energy required______b. Practice: Start of experiment: Semi-permeable tube (to water) contains 20% sucrose immersed in 100% water. Arrows moving in show start of osmosis. 1. What substance is moving into the tube? _water______2. Is it moving ‘up the concentration gradient’ or ‘down the concentration gradient’? _’down the concentration gradient’______5 ½ points possible At equilibrium: ¼ point each = ¾ point 1. Which solution has increased in volume, the sucrose in the tube or the water in the beaker? _sucrose in tube______2. What is moving up the tube? _solution of sucrose and water______

At start of experiment At equilibrium Figure 3.7, page 53: 1 point 1. Will the fluid level in the tube continue to rise until concentrations are the same in the beaker and in the tube? _no, water concentration can never be the same because the beaker always contains 100% pure water and the tube contains a solution that is less than 100% water______¼ point each = 1 ½ points

4 c. Osmotic pressure: _pressure exerted on membrane because solute particles cannot cross membrane; depends on concentration of solute concentration: high solute concentration = higher osmotic pressure; low solute concentration = lower osmotic pressure______(1) Isotonic solution: _concentration equal______(2) Hypotonic solution: _concentration of water higher outside______Condition of bursting red blood cells known as: _hemolysis______(3) Hypertonic solution: _concentration of water higher inside______Condition of shrinkage of red blood cells known as: _crenation______

Crenation Normal Hemolysis

Figure 3.8, page 54: 1 point Look over and study Figure 3.8 on page 54, then answer the following question: 1. Will a 2 percent solution of NaCl cause hemolysis or crenation in red blood cells (RBCs)? Justify your answer by explaining how you derived it. _2% solution of NaCl will cause crenation of RBCs because it is hypertonic; water will move out of RBCs______4 ¼ points possible B. Active Processes ¼ point each = 2 points 1. Active Transport a. _transport materials across membrane from low to high concentration; ‘up the concentration 5 gradient’______b. _requires the use of energy______- Comes from splitting of _ATP molecule______- Changes shape of _transporter molecules_, called a _pump_ - Transports ions: _Na+, K+, H+, Ca2+, I-, and Cl-______- _40%_ of a cell’s ATP expended on active transport What drug can be lethal to ATP production? _cyanide______Figure 3.9, page 55: 1 point each = 2 points Look at Figure 3.9 on page 55 and read over the section on Active Transport on page 55 in your textbook. 1. Explain how the sodium- potassium pump works. _ sodium-potassium pump expels sodium (3) from cell and brings in potassium (2) and acts as an enzyme to split ATP______2. What is the role of ATP in the operation of the sodium-potassium pump? _ ATP adds a phosphate group to the pump protein, which changes the pump’s three-dimensional shape ___ 2. Transport in Vesicles ¼ point each = 2 ¾ points a. _vesicles_: small sacs formed by budding off of membranes b. Functions: (1) _Transport substances within the cell from one structure to another______(2) _Take in substances from ECF and transport substances out to ECF______c. Two main types of vesicular transport: _endocytosis_ and _exocytosis_ ENDOCYTOSIS

_materials moved into cell; capturing substance or particle from outside the cell by engulfing it within membrane folds from the cell membrane and releasing it into cytosol Two types of endocytosis: 1. Phagocytosis: _”cellular eating”______(1) Attachment: _ Particles bind to plasma membrane receptors______(2) Phagosome formation: _Projections called pseudopods extend surround particles and portions of the membrane fuse to form a vesicle; extensions of the 6 plasma membrane and cytoplasm; pseudopods vesicle formed called a

phagosome______(3) Phagosome-lysosome fusion: _ Phagosome enters the cell, fuses with lysosomes (4) Digestion: _ Lysosome enzymes break down phagosome’s contents; any undigested content remains in the phagosome, now called a residual body____ What types of cells does this only occur in? _phagocytes (certain white blood cells and macrophages)______

2. Bulk-phase Endocytosis: _”cellular drinking” [pinocytosis]______(1) _plasma membrane folds inwards_, forms pinocytotic vesicle that pulls in _tiny droplets of ECF containing dissolved substances_ to be surrounded (2) Vesicles _detaches or “pinches off”_ of plasma membrane enter _cytosol_ (3) Vesicles fuse with _lysosome_, and then _enzymes_degrade engulfed solutes (4) Degraded solutes, like _amino acids_ and _fatty acids_ leave lysosome to be used elsewhere in the cell 6 ¾ points possible EXOCYTOSIS ¼ point each = 1 point _materials removed from cell; process of vesicles fusing with the plasma membrane and secretes their contents to the outside of the cell______Do all cells carry out exocytosis? _yes______Exocytosis is most important in these two types of cells: (1) _secretory cells______

7 Release digestive enzymes, hormones, mucus, and other secretions (2) _nervous cells______Releases neurotransmitters

CHECKPOINT: 2 points 1. What is the key difference between passive and active transport? _passive  high to low concentration; needs no energy/ active low to high concentration; needs energy______IV. Cytoplasm ¼ point each = 2 ¼ points OBJ: Describe the structure and Functions of cytoplasm, cytosol, and organelles. 1. Cytoplasm defined: _everything inside plasma membrane excluding nucleus ______A. Cytosol 1. Cytosol defined: _ everything inside plasma membrane excluding nucleus and membrane-bound organelles______

2. What is cytosol composed of? _ 75%-90% of cytosol is water, the rest is composed of dissolved solutes and suspended particles ______3. What do the chemical reactions that occur in the cytosol help the cell with? _ Maintain cell structure and enable cell growth______CYTOSKELETON a. Extends throughout cytosol b. Network of three different types of protein filaments: – _microfilaments______– _intermediate filaments______– _microtubules______c. Microfilament functions: – Provide mechanical support and help generate movement – Anchor cytoskeleton to integral proteins – Provide support for microvilli 8 d. Microvilli functions: – Muscle contractions – Cell division – Cell locomotion e. Intermediate filaments functions: – Found in parts of cells subjected to tension (stretching) – Hold organelles in place – Attach cells to one another f. Microtubules functions: – Help determine cell shape – Function as transport system for organelle movement – Secretory vesicles – Migration of chromosomes – Create movement of cilia and flagella 5 ¼ points possible B. Organelles ¼ point each = 3 ½ points Label the lettered organelles on the diagram pictured below : A.1.a. smooth ER A.1.b. GOLGI COMPLEX A.1.c. MITOCHONDRIA A.1.d. ROUGH ER A.1.e. RIBOSOMES A.1.f. CILIA A.1.g. MICROVILLI A.1.h. CENTRIOLES A.1.i. NUCLEOLUS A.1.j. LYSOSOME A.1.k. PLASMA MEMBRANE A.1.l. PEROXISOME A.1.m. NUCLEUS A.1.n. CYTOSOL/CYTOPLASM Describe briefly the function of each organelle listed below: ¼ point each = 2 ¾ points 1. Centrosome: role in cell division 2. Cilia: motile projections; increase surface area 3. Flagella: motile projections 4. Ribosomes: synthesize proteins 5. Rough Endoplasmic Reticulum: production of proteins for export 6. Smooth Endoplasmic Reticulum: site of lipid synthesis 7. Golgi Complex: sorts, modifies, packages proteins & lipids; forms lysosomes 8. Lysosomes: vesicles with digestive enzymes

9 9. Peroxisomes: vesicles with enzymes to detoxify drugs, alcohol, harmful substances; hydrogen peroxide 10. Proteasomes: vesicles that dispose of dying cells 11. Mitochondria: site of ATP production CHECKPOINT: 2 points each = 4 points total 1. What does cytoplasm have that cytosol does not? _includes membrane- bound organelles___ 2. What is an organelle? _specialized structures inside cells that have specific shapes and functions V. Nucleus ¼ point each = 1 ¾ points OBJ: Describe the structure and functions of the nucleus. Label the lettered organelles on the diagram pictured below : A. NUCLEAR ENVELOPE B. CHROMATIN C. NUCLEOLUS D. NUCLEAR PORES E. ROUGH ER F. POLYRIBOSOMES Describe briefly the function of nucleus below: controls cellular structure, directs cellular activity, produces ribosomes in nucleoli CHECKPOINT: 2 points 1. Why is the nucleus so important in the life of a cell? _because it contains the genes that control cellular activity and cellular structure and pass on hereditary traits______

12 ¼ points possible VI. Gene Action: Protein Synthesis ¼ point each = 2 points OBJ: Outline the sequence of events involved in protein synthesis. 1. What do the proteins made during protein synthesis determine for cells and organisms? Physical and chemical characteristics of cells/organisms 2. Where in the cell and on what is the code for making proteins stored? Genes on DNA in cell nucleus 3. Define protein synthesis. The making of protein molecules through transcription and translation processes A. Transcription 1. Where does this process take place in the cell? Cell nucleus 10 2. What enzyme catalyzes this process? RNA polymerase 3. Compare the three types of RNA (you may need to do some research) in the chart below:

B. Translation 1. What happens during translation? Process in which mRNA associates with ribosomes and directs synthesis of protein by converting the sequence of nucleotides in mRNA into a specific sequence of amino acids 2. Label and color (first fill in the color key on the lower right side) the chart below: ¼ point colored in; ½ point molecule colored in; 1 point each step 1 &2 = 3 points

5 ¼ points possible ¼ point each = 1 ½ points 11

VII. Somatic Cell Division ¼ point each = 1 ½ points OBJ: Discuss the stages, events, and significance of somatic cell division. 1. Why are body cells replaced? _because they become damaged, diseased, or worn out______A. Interphase 1. What is the first step? _nucleus replicates DNA______2. What else occurs during interphase? _cell manufactures additional organelles and cytosolic components in anticipation of cell division______B. Mitotic Phase 1. What becomes visible during this phase? _chromosomes______1. Nuclear Division: Mitosis a. Four stages: (1) _prophase______- _chromatin fibers condense and shorten into chromosomes______- _chromosomes become chromatids______- _centromeres hold chromatids together______- _mitotic spindles form______(2) _metaphase______- _centromeres align along metaphase plate______(3) _anaphase______- _centromeres split, separating chromatid pairs______- _chromatids pulled by spindles to opposite poles______

12 (4) _telophase______- _chromosomes stop moving ______- _ nuclear envelope starts to reform ______- _chromatin condenses______- _cell pinches inward forming cleavage furrow______2. Cytoplasmic Division: Cytokinesis a. Division of the _cytoplasm______b. Begins with formation of a _cleavage furrow_ in plasma membrane that pinches inward VIII. Cellular Diversity OBJ: Describe how cells differ in size and shape. • Average humans has about 100 trillion cells of varying sizes – Cell size is measured in micrometers (µm) • 1 micrometer = 1 one-millionth of a meter • Largest cell in human body is an oocyte with a diameter of 140 µm – Average hair strands is ~100 µm in diameter • Cells can be round, oval, flat, cube-shaped, column-shaped, elongated, star- shaped, cylindrical, or disc-shaped – Shape is related to function ** An oocyte is a female germ cell or gamete. 5 points possible Figure 3.22, page 69: 1 point ; ¼ point each 1. How is the shape of the cells in Figure 3.22 related to their functions? Sperm cell: uses flagella for locomotion Nerve cell: dendrites like telephone wires to transmit messages Smooth muscle cell: long cylinder to allow it to stretch and contract Red blood cell: disc-shaped to allow ease of movement through circulatory system without risk of clogging IX. Aging and Cells OBJ: Describe the cellular changes that occur with aging As we age our cells ability to divide is diminished. DNA sequences that code for cell division break down. Free radical control becomes limited. Autoimmune responses slow down.

Critical thinking applications: 2 points each = 4 points

13 1. Jethro loves his French fries super-sized with extra salt. He dropped

Anatomy & Physiology last semester but remembers something about a pump.

“Hey, I’m a big guy. I need the extra salt to power my sodium pump.” How

well does Jethro remember his Anatomy & Physiology?

Salt is composed of sodium and chloride; sodium-potassium pump transports

sodium out of the cell and potassium into the cell by active transport. ATP

powers the pump.

2. Your friend Sam works a highly stressful job as a neurosurgeon. His diet

during long, extended shifts consists mainly of chocolate and Sweet Ice Tea.

He has been sick a lot and feels that his job is prematurely aging him. Your

response to Sam is that he should examine his diet. Why do you respond this

Sam has several risk factors that could be contributing to his “premature

aging”. High levels of stress can shorten the protective telomeres on the

ends of chromosomes, contributing to aging and eventual death of cells.

Glucose cross-links that form between proteins can contribute to loss of

elasticity, which ages tissues. His immune system may be malfunctioning,

producing autoimmune responses that can also affect the aging process.