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2 A&P I The Cell 10


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Power Point II for Dr. Krasilovsky's Bio 110

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2 A&P I The Cell 10

  1. 1. BIO 110 UNIT II - THE CELL STRUCTURE & FUNCTION Chap. 3 pp. 61 - 95
  2. 2. I. Cell Theory A. History <ul><li>1. Robert Hooke - 1668 </li></ul><ul><ul><li>British scientist - microscope exhibit </li></ul></ul><ul><ul><li>Thin slice of cork - outer bark of tree </li></ul></ul><ul><ul><li>Coined the term “cell” </li></ul></ul>
  3. 3. 2. Different scientists examined many different plants and animals for the next 200 years - always found CELLS <ul><li>B. Cell Theory - 1850s </li></ul><ul><ul><li>Theory - based upon fact and many observations </li></ul></ul><ul><li>1. The cell is the basic unit of structure of all living things </li></ul><ul><li>2. The cell is the basic unit of function of all living things </li></ul><ul><li>3. All cells come from other pre-existing living cells </li></ul>
  4. 5. C. Form and Function 1. Something is built in a certain way, for the job it must do <ul><li>Muscle cells contract - contain contractile proteins </li></ul><ul><li>Bone cells support and protect - hard calcium salts </li></ul><ul><li>1mm = 1000micrometers(um) </li></ul><ul><ul><li>Most cells 40 to 70 um </li></ul></ul><ul><li>Surface - volume relationship </li></ul><ul><ul><li>Surface increases as square of radius </li></ul></ul><ul><ul><li>Volume increases as cube of radius </li></ul></ul><ul><ul><li>Volume increases faster than surface area - what do cells do??? </li></ul></ul>
  5. 7. II. Cell Membrane Structure <ul><li>1. Physical barrier or boundary around cell </li></ul><ul><li>2. Not just a barrier for blockage </li></ul><ul><ul><li>Also a gateway for passage through </li></ul></ul><ul><li>3a. Permeable membrane = all materials (in question) can pass through </li></ul><ul><li>3b. Semi-permeable or selectively permeable = some materials can pass through, but others cannot pass through </li></ul><ul><li>All biological/cellular membranes are semi permeable </li></ul>
  6. 8. 4. Interested in the chemicals that make up the cell membrane <ul><li>Fluid Mosaic Model of the Membrane </li></ul><ul><ul><li>1972 - Singer and Nicolson </li></ul></ul><ul><li>Phospholipids or fats </li></ul><ul><li>Proteins </li></ul><ul><li>Carbohydrates </li></ul><ul><li>Cholesterol </li></ul>
  7. 10. 5. Functions of chemicals <ul><li>a) phospholipids & cholesterol: </li></ul><ul><ul><li>Strengthen membrane </li></ul></ul><ul><ul><li>Increase permeability to other fats/oils </li></ul></ul><ul><ul><li>Reduce permeability to water and water soluble chemicals </li></ul></ul><ul><li>b) proteins: increase solubility to water soluble chemicals </li></ul><ul><ul><li>Carriers for transport - aid other chemicals </li></ul></ul><ul><ul><li>Membrane enzymes - control specific reactions </li></ul></ul><ul><ul><li>Receptors - on outer surface to allow other chemicals to react with cell </li></ul></ul>
  8. 11. 5. Functions of chemicals (continued) <ul><li>c) carbohydrates: </li></ul><ul><ul><li>Found only on outside surface of membrane </li></ul></ul><ul><ul><li>Found associated with lipids = glycolipids </li></ul></ul><ul><ul><li>Found associated with proteins = glycoproteins </li></ul></ul><ul><ul><li>These chemicals allow the cell to be recognized as belonging to that individual……and not as a foreign cell </li></ul></ul><ul><ul><li>Basis of our immune reactions </li></ul></ul>
  9. 12. 6. Structural arrangement of chemicals
  10. 20. Fig.3.3
  11. 23. Fig. 3.4
  12. 25. 7. Cell membrane has channels or pores (doorway) to let other chemicals pass in or out of the cell <ul><li>Lipid pore allows fats to easily pass through </li></ul><ul><li>Protein pores allows water soluble materials to pass in or out of the cell </li></ul><ul><li>Either pores can be open or closed </li></ul>
  13. 26. 8. Membrane is a dynamic structure - both in its chemical make-up and its functions <ul><li>Constantly capable of change </li></ul><ul><li>As chemical change, so does the functions of that membrane/cell </li></ul><ul><li>Pores opening or closing </li></ul><ul><li>Solubility changes </li></ul>
  14. 27. 9. Micovilli - folds of the cell membrane to increase surface area <ul><li>Volume of the cell does not change </li></ul><ul><li>Surface area increases </li></ul><ul><li>Pancreas cells during a fast - flat surface </li></ul><ul><li>Same cells following eating - look to left </li></ul><ul><li>Increase transport across membrane </li></ul>
  15. 28. 9. Micovilli - folds of the cell membrane to increase surface area <ul><li>Volume of the cell does not change </li></ul><ul><li>Surface area increases </li></ul><ul><li>Pancreas cells during a fast - flat surface </li></ul><ul><li>Same cells following eating - look to left </li></ul><ul><li>Increase transport across membrane </li></ul>
  16. 29. III. Passive Transport - cell does not expend any energy - is energy expended at all? A. Diffusion <ul><li>1. Movement of materials from one area to another </li></ul><ul><li>2. Movement - built in to all chemicals - energy of vibration ( gases in air: O 2 CO 2 H 2 O N 2 ) </li></ul><ul><li>3. Factors influencing vibration </li></ul><ul><ul><li>Temperature </li></ul></ul><ul><ul><li>Collisions </li></ul></ul><ul><ul><li>Charge + or - </li></ul></ul><ul><ul><li>Gas>liquid>solid </li></ul></ul>
  17. 30. 4. Solute - a chemical (solid) that is mixed or dissolved in a liquid <ul><li>Solvent - a liquid that a chemical or solute is dissolved in </li></ul><ul><li>Concentration - how much solute/solvent ratio </li></ul><ul><ul><li>10% salt + 90% water = 100% solution </li></ul></ul><ul><ul><li>3% sugar + 97% water = 100% solution </li></ul></ul><ul><li>5% sucrose solution in beaker & pool </li></ul><ul><ul><li>Which is more concentrated? </li></ul></ul>
  18. 32. 5. Equilibrium <ul><li>A B </li></ul><ul><li>10% salt 20% salt </li></ul><ul><li>90% H 2 O 80% H 2 O </li></ul><ul><li> permeable membrane </li></ul><ul><li>A B </li></ul><ul><li>10% salt 20% salt A B </li></ul><ul><li> 90% H 2 O 80% H 2 O </li></ul><ul><li>A B </li></ul><ul><li>15% salt 15% salt </li></ul><ul><li>85% H 2 O 85% H 2 O EQUILIBRIUM = equal and opposite </li></ul>
  19. 34. <ul><li>B. Facilitative Diffusion 1. no expenditure of cell energy </li></ul><ul><li>2. BY ITSELF -a chemical cannot penetrate the cell membrane </li></ul><ul><ul><li>Amino acids - glucose </li></ul></ul><ul><li>3. Chemical plus protein carrier in the cell membrane - together - can move across the membrane </li></ul><ul><li>4. Combination of carrier + chemical net diffuses from area of high to area of lower concentration </li></ul>
  20. 35. Facilitative Diffusion <ul><li>(a) channel (b) revolving </li></ul><ul><li> door channel </li></ul>See Fig. 3.7b-c in text
  21. 36. C. Osmosis - passive transport(continued) <ul><li>1. Osmosis - movement of solvent (water) across a semi-permeable membrane </li></ul><ul><ul><li>Why is it semi-permeable? </li></ul></ul><ul><li>2. Net Osmosis - movement of solvent across a semi-permeable membrane from area of higher solvent concentration to lower solvent concentration </li></ul>
  22. 37. Fig. 3.8a
  23. 38. Fig. 3.8b
  24. 39. 3a. Another example of osmosis <ul><li>10% sucrose surrounded by 100% H 2 O </li></ul><ul><li> water </li></ul><ul><li>Will sucrose move through membrane? </li></ul><ul><li>Will water move through membrane? </li></ul><ul><ul><li>Which direction or directions? </li></ul></ul><ul><ul><li>Net osmosis has water moving into the cell </li></ul></ul>10% sucrose 90% water
  25. 40. 3c. Another example of osmosis <ul><li>10% sucrose surrounded by 100% H 2 O </li></ul><ul><li> water </li></ul><ul><li> after net osmosis </li></ul><ul><li>into the cell/bag </li></ul><ul><li>before water </li></ul>7+% sucrose 93-% water 10% sucrose 90% water
  26. 41. 3b. Another example of osmosis <ul><li>10% sucrose surrounded by 100% H 2 O </li></ul><ul><li>water </li></ul><ul><li>Water enters due to Water leaves due to </li></ul><ul><li>CONCENTRATION PRESSURE INCREASE </li></ul><ul><li>GRADIENT WITHIN BAG </li></ul>10% sucrose 90% water
  27. 42. 4. Osmotic pressure <ul><li>Measure of the tendency for water to move into a solution due to osmosis </li></ul><ul><li>Pressure that develops (or can be calculated) due to net osmosis of water across a semi-permeable membrane </li></ul><ul><li>Pressure pushes water one way EQUAL to water moving other way due to concentration gradient = Equilibrium </li></ul><ul><li>At equilibrium, pressure does not change </li></ul>
  29. 47. D. Passive Transport Summary <ul><li>1. Diffusion is a slow process </li></ul><ul><ul><li>Narrow the space or gap for diffusion - lungs and capillaries </li></ul></ul><ul><ul><li>Artificially increase concentration gradient to speed up net diffusion by compartmentalizing a chemical </li></ul></ul><ul><ul><li>A </li></ul></ul><ul><ul><li>B </li></ul></ul>
  30. 48. <ul><li>2. Protista - singled celled organism in a hypotonic environment - need a contractile vacuole to remove water that net osmosed into hypertonic cell </li></ul><ul><li>3. Plants </li></ul><ul><ul><li>Young plants hypertonic to environment </li></ul></ul><ul><ul><li>Water enters </li></ul></ul><ul><ul><li>Pressure increases inside - turgor pressure </li></ul></ul><ul><ul><li>Aids in support and growth of young plant since cell wall not yet rigid </li></ul></ul><ul><ul><li>Problem with too much fertilizer???? </li></ul></ul>
  31. 50. IV. Active transport <ul><li>1. Cell expends energy </li></ul><ul><ul><li>ATP = cellular energy </li></ul></ul><ul><ul><li>Cell must be alive to produce ATP </li></ul></ul><ul><li>2. Carrier protein in membrane requires energy to work (not like facilitative diffusion) </li></ul><ul><li>3. Chemical movement from an area of LOW concentration to area of HIGHER concentration (push a rock uphill) </li></ul>
  32. 51. 4. Endocytosis - change in membrane structure to bring a chemical into the cell <ul><li>a) Phagocytosis - engulfing solid materials </li></ul><ul><li>b) Pinocytosis - engulfing fluids / water and solutes dissolved in fluid </li></ul><ul><li>5. Exocytosis - release of wastes or secretions from the cell to the outside environment </li></ul>
  33. 52. Fig. 3.12-13
  34. 55. V. Internal Area of Cells
  35. 56. A-B. Nucleus <ul><li>1. Function - controls metabolism of cell and its related activities - growth..development..reproduction </li></ul><ul><li>2. Nuclear Membrane - semi-permeable (double) membrane that separates nucleus from rest of cell (cytoplasm) </li></ul><ul><ul><li>Contain pores/breaks in the membrane to increase permeability </li></ul></ul>
  36. 57. Fig. 3.29
  37. 58. 3. Nuclear Membrane basis of cell classification <ul><li>Prokaryotic Cell - cells with NO nuclear membrane and no internal membrane structure </li></ul><ul><li>Eukaryotic Cell - cells with nuclear membrane plus complex cytoplasmic membranes </li></ul>
  38. 59. <ul><li>4. Chromosomes a) consist of DNA (Deoxyribonucleic acid) & proteins </li></ul><ul><li>b) units of genetic information or heredity -”genes” </li></ul><ul><li>c) human cell has 46 chromosomes in every cell of the body, except the sex/germ cells </li></ul><ul><li>d) all cells have the same 46 chromosomes - how do you “make” a muscle cell vs. bone cell??? </li></ul><ul><ul><li>Different piano tunes with the same 88 keys </li></ul></ul><ul><ul><li>Selectively turn genes on and off </li></ul></ul>
  39. 60. 5. Nucleolus <ul><li>a) 1 or more “balls” of DNA within nucleus </li></ul><ul><li>b) function - synthesis of Ribosomes </li></ul><ul><li>c) ribosomes - make proteins in the cytoplasm after leaving the nucleus </li></ul>
  40. 62. C. Cytoplasm and its Organelles <ul><li>1. Variety of chemicals that all interact, within an area between the cell membrane and the nucleus. </li></ul><ul><ul><li>Cytoplasm contains membrane bound organelles </li></ul></ul><ul><li>2. Solvent water with solutes - </li></ul><ul><ul><li>Salts Sugars </li></ul></ul><ul><ul><li>Amino acids Proteins </li></ul></ul><ul><ul><li>Fats </li></ul></ul><ul><ul><li>This combination of solutes gives cytoplasm an interesting property - </li></ul></ul>
  41. 63. <ul><li>3. Cytoplasmic Streaming a) sol = liquid/fluid properties </li></ul><ul><li>b) gel = semi-solid solute held in 3-D array </li></ul><ul><li>c) cytoplasmic streaming = cyclosis </li></ul><ul><ul><li>Amoeboid movement </li></ul></ul><ul><ul><li>White blood cell movement </li></ul></ul><ul><li>d) factors influencing cyclosis </li></ul><ul><ul><li>Temperature </li></ul></ul><ul><ul><li>Pressure </li></ul></ul><ul><ul><li>Salt concentration </li></ul></ul>
  42. 65. 4. Endoplasmic Reticulum (ER) and Ribosomes <ul><li>a) network of membranes within the cytoplasm </li></ul><ul><li>b) functions of ER: </li></ul><ul><ul><li>System of channels for transport within the cell </li></ul></ul><ul><ul><ul><li>Channels can connect the cell membrane and the nuclear region </li></ul></ul></ul><ul><ul><li>Area in cell where steroids (chemicals) are produced ( smooth ER ) </li></ul></ul>
  43. 66. c) Ribosomes <ul><li>(1) produced in the nucleus by the nucleolus </li></ul><ul><li>(2) function in protein synthesis by attaching amino acids together to produce proteins </li></ul><ul><li>(3)found in two places </li></ul><ul><ul><li>Free in cytoplasm = making proteins that stay in the cell </li></ul></ul><ul><ul><li>Ribosomes + ER = Rough ER - make proteins that leave the cell and work extracellularly </li></ul></ul>
  44. 67. Fig. 3.18
  45. 69. 5. Golgi Bodies/Apparatus <ul><li>a) Structure - stack of flatten membranes </li></ul><ul><li>b) Function of Golgi - after leaving the ER, many transport vesicles travel to the Golgi and are modified, sorted and shipped </li></ul>
  46. 70. Figs. 3.20
  47. 72. b) Function continued <ul><li>1) store proteins made in the ER </li></ul><ul><li>2) Some Golgi synthesize or modify carbohydrates (previously synthesized) </li></ul><ul><li>3) combine carbohydrates to proteins (glycoproteins) (or glycolipids) </li></ul><ul><li>4) package glycoproteins in vesicles </li></ul><ul><li>5) vesicle moves towards cell membrane and releases glycoprotein outside the cell (Secretion) </li></ul><ul><li>6) vesicle can become part of the membrane </li></ul>
  48. 77. 6. Lysosomes <ul><li>a) vesicles that are produced by the Golgi, but remain within the cell, and contain strong digestive/hydrolytic enzymes </li></ul><ul><li>b) function: </li></ul><ul><ul><li>Destroy bacteria that enter cell </li></ul></ul><ul><ul><li>Join with endocytosis vacuole that enters cell with food source - Protista - and digests food </li></ul></ul><ul><ul><li>Destroy worn out organelles that do not function anymore </li></ul></ul>
  49. 78. 6. Lysosome (continued) <ul><li>c) problem if lysosomes become unstable and its membrane ruptures </li></ul><ul><ul><li>Digestive enzymes released into cytoplasm </li></ul></ul><ul><ul><li>Start destroying cell - “suicide bags” </li></ul></ul><ul><ul><li>Aging has been associated with lysosomal instability </li></ul></ul><ul><ul><li>Degenerative diseases of muscles (MD) and nervous system </li></ul></ul><ul><ul><li>Attempt to treat with drugs that stabilize lysosomal membranes </li></ul></ul>
  50. 80. Fig. 3.21
  51. 82. 7. Vacuole <ul><li>a) membrane bound storage area of cytoplasm </li></ul><ul><li>Store water…food…wastes </li></ul><ul><li>Animal cells contain numerous, small vacuoles </li></ul><ul><li>Plant cells contain one centrally located vacuole </li></ul><ul><ul><li>Turgor pressure </li></ul></ul>
  52. 85. 8. Mitochondria <ul><li>a) “powerhouse” of the cell - production of aerobic cellular energy (ATP) </li></ul><ul><li>b) muscle cells need energy - contain many mitochondria </li></ul>
  53. 86. <ul><li>c) structure - double mosaic membrane with outer and inner membranes </li></ul><ul><ul><li>Inner contains folds = Cristae to increase surface area (more chemical reactions = more ATP) </li></ul></ul>Fig. 3.17
  54. 87. d) Mitochondria contain DNA <ul><ul><li>Different from nuclear DNA </li></ul></ul><ul><li>e) mitochondria from different organisms contain similar DNA </li></ul><ul><li>f) billions of years ago - mitochondria were a free living Prokaryotic bacteria that could use oxygen = Aerobic </li></ul>
  55. 88. Mitochondria Origin- Hypothesis Endosymbiosis Aerobic Anaerobic
  56. 89. 10. Microtubules and Microfilaments (Fig. 3.24) <ul><li>a) part of cell / cytoplasm but no membrane surrounding each structure </li></ul><ul><li>b) Filaments </li></ul><ul><ul><li>Protein in nature </li></ul></ul><ul><ul><li>Thick and thin </li></ul></ul><ul><ul><li>Function - contractile and/or shape of cell </li></ul></ul><ul><ul><ul><li>Muscle protein/contractile protein </li></ul></ul></ul><ul><ul><ul><li>Movement of Golgi vesicles to outer membrane </li></ul></ul></ul>
  57. 93. c) Microtubules <ul><li>Arrangement of several microfilaments </li></ul><ul><li>Transport of materials </li></ul><ul><li>Maintenance of cell shape </li></ul><ul><li>Component of cilia and flagella for cell motility </li></ul>
  58. 95. 11. Centrioles <ul><li>a) animal microtubular arrangement </li></ul><ul><li>b) pair </li></ul><ul><li>c) cell division - organize formation of spindle fibers </li></ul>
  59. 97. 12. Cilia and Flagella <ul><li>a) microtubular in structure </li></ul><ul><li>Cilia - numerous, small projections from the cell surface </li></ul><ul><ul><li>cell movement or transports materials along the surface of cell </li></ul></ul><ul><ul><li>Oar like motion - power stroke plus recovery </li></ul></ul><ul><li>Flagellum - 1 or 2 longer microtubular structures for movement of entire cell </li></ul><ul><ul><li>Sperm or Euglena </li></ul></ul>
  60. 102. Cells
  61. 103. 13. Summary: Form and Function something is built in a certain way, for the job it will do <ul><li>Function Cell Structure </li></ul><ul><li>Stores fats adipose/fat </li></ul><ul><ul><li>large vacuole </li></ul></ul><ul><li>Contracts muscle cell </li></ul><ul><ul><li>contractile filaments and </li></ul></ul><ul><ul><li>mitochondia / energy </li></ul></ul><ul><li>Phagocytosis Bacteria </li></ul><ul><ul><li>white blood cell </li></ul></ul><ul><ul><li>lysosomes </li></ul></ul><ul><li>Release Digestive enzymes - Pancreas </li></ul><ul><ul><li>Golgi </li></ul></ul><ul><ul><li>Rough ER </li></ul></ul><ul><ul><li>Microvilli </li></ul></ul>
  62. 104. THE END