Start here_ch03_lecture

23,312 views

Published on

Published in: Education, Technology
2 Comments
12 Likes
Statistics
Notes
No Downloads
Views
Total views
23,312
On SlideShare
0
From Embeds
0
Number of Embeds
16,798
Actions
Shares
0
Downloads
516
Comments
2
Likes
12
Embeds 0
No embeds

No notes for slide

Start here_ch03_lecture

  1. 1. Chapter 3 Cell Structure and Function
  2. 2. Processes of Life <ul><li>Growth </li></ul><ul><li>Reproduction </li></ul><ul><li>Responsiveness </li></ul><ul><li>Metabolism </li></ul>
  3. 3. Processes of Life
  4. 4. Prokaryotic & Eukaryotic Cells: An Overview [INSERT FIGURE 3.1]
  5. 5. Prokaryotic & Eukaryotic Cells: An Overview <ul><li>Prokaryotes </li></ul><ul><ul><li>Do not have membrane surrounding their DNA; lack a nucleus </li></ul></ul><ul><ul><li>Lack various internal structures bound with phospholipid membranes </li></ul></ul><ul><ul><li>Are small, ~1.0 µm in diameter </li></ul></ul><ul><ul><li>Have a simple structure </li></ul></ul><ul><ul><li>Composed of bacteria and archaea </li></ul></ul>
  6. 6. Prokaryotic & Eukaryotic Cells: An Overview [INSERT FIGURE 3.2]
  7. 7. Prokaryotic & Eukaryotic Cells: An Overview <ul><li>Eukaryotes </li></ul><ul><ul><li>Have membrane surrounding their DNA; have a nucleus </li></ul></ul><ul><ul><li>Have internal membrane-bound organelles </li></ul></ul><ul><ul><li>Are larger, 10-100 µm in diameter </li></ul></ul><ul><ul><li>Have more complex structure </li></ul></ul><ul><ul><li>Composed of algae, protozoa, fungi, animals, and plants </li></ul></ul>
  8. 8. Prokaryotic & Eukaryotic Cells: An Overview [INSERT FIGURE 3.3]
  9. 9. Prokaryotic & Eukaryotic Cells: An Overview [INSERT FIGURE 3.4]
  10. 10. External Structures of Prokaryotic Cells <ul><li>Glycocalyces </li></ul><ul><ul><li>Gelatinous, sticky substance surrounding the outside of the cell </li></ul></ul><ul><ul><li>Composed of polysaccharides, polypeptides, or both </li></ul></ul>
  11. 11. External Structures of Prokaryotic Cells <ul><li>Two Types of Glycocalyces </li></ul><ul><ul><li>Capsule </li></ul></ul><ul><ul><ul><li>Composed of organized repeating units of organic chemicals </li></ul></ul></ul><ul><ul><ul><li>Firmly attached to cell surface </li></ul></ul></ul><ul><ul><ul><li>Protects cells from drying out </li></ul></ul></ul><ul><ul><ul><li>May prevent bacteria from being recognized and destroyed by host </li></ul></ul></ul><ul><ul><li>Slime layer </li></ul></ul><ul><ul><ul><li>Loosely attached to cell surface </li></ul></ul></ul><ul><ul><ul><li>Water soluble </li></ul></ul></ul><ul><ul><ul><li>Protects cells from drying out </li></ul></ul></ul><ul><ul><ul><li>Sticky layer that allows prokaryotes to attach to surfaces </li></ul></ul></ul>
  12. 12. External Structures of Prokaryotic Cells [INSERT FIGURE 3.5]
  13. 13. External Structures of Prokaryotic Cells Animation: Motility
  14. 14. External Structures of Prokaryotic Cells <ul><li>Flagella </li></ul><ul><ul><li>Are responsible for movement </li></ul></ul><ul><ul><li>Have long structures that extend beyond cell surface </li></ul></ul><ul><ul><li>Are not present on all prokaryotes </li></ul></ul>
  15. 15. External Structures of Prokaryotic Cells <ul><li>Flagella </li></ul><ul><ul><li>Structure </li></ul></ul><ul><ul><ul><li>Composed of filament, hook, and basal body </li></ul></ul></ul><ul><ul><ul><li>Flagellin protein (filament) deposited in a helix at the lengthening tip </li></ul></ul></ul><ul><ul><ul><li>Base of filament inserts into hook </li></ul></ul></ul><ul><ul><ul><li>Basal body anchors filament and hook to cell wall by a rod and a series of either two or four rings of integral proteins </li></ul></ul></ul><ul><ul><ul><li>Filament capable of rotating 360º </li></ul></ul></ul>
  16. 16. External Structures of Prokaryotic Cells Animation: Flagella Structure
  17. 17. External Structures of Prokaryotic Cells [INSERT FIGURE 3.6]
  18. 18. External Structures of Prokaryotic Cells
  19. 19. External Structures of Prokaryotic Cells Animation: Flagella Arrangement
  20. 20. External Structures of Prokaryotic Cells [INSERT FIGURE 3.8]
  21. 21. External Structures of Prokaryotic Cells <ul><li>Flagella </li></ul><ul><ul><li>Function </li></ul></ul><ul><ul><ul><li>Rotation propels bacterium through environment </li></ul></ul></ul><ul><ul><ul><li>Rotation reversible, can be clockwise or counterclockwise </li></ul></ul></ul><ul><ul><ul><li>Bacteria move in response to stimuli (taxis) </li></ul></ul></ul><ul><ul><ul><ul><li>Runs </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Tumbles </li></ul></ul></ul></ul>
  22. 22. External Structures of Prokaryotic Cells [INSERT FIGURE 3.9]
  23. 23. External Structures of Prokaryotic Cells Animation: Flagella Movement
  24. 24. External Structures of Prokaryotic Cells <ul><li>Fimbriae and Pili </li></ul><ul><ul><li>Rod-like proteinaceous extensions </li></ul></ul>
  25. 25. External Structures of Prokaryotic Cells <ul><ul><li>Fimbriae </li></ul></ul><ul><ul><ul><li>Sticky, bristlelike projections </li></ul></ul></ul><ul><ul><ul><li>Used by bacteria to adhere to one another, to hosts, and to substances in environment </li></ul></ul></ul><ul><ul><ul><li>Shorter than flagella </li></ul></ul></ul><ul><ul><ul><li>May be hundreds per cell </li></ul></ul></ul><ul><ul><ul><li>Serve an important function in biofilms </li></ul></ul></ul>
  26. 26. External Structures of Prokaryotic Cells [INSERT FIGURE 3.10]
  27. 27. External Structures of Prokaryotic Cells <ul><li>Pili </li></ul><ul><ul><li>Tubules composed of pilin </li></ul></ul><ul><ul><li>Also known as conjugation pili </li></ul></ul><ul><ul><li>Longer than fimbriae but shorter than flagella </li></ul></ul><ul><ul><li>Bacteria typically only have one or two per cell </li></ul></ul><ul><ul><li>Mediate the transfer of DNA from one cell to another (conjugation) </li></ul></ul>
  28. 28. External Structures of Prokaryotic Cells [INSERT FIGURE 3.11]
  29. 29. Prokaryotic Cell Walls <ul><li>Provide structure and shape and protect cell from osmotic forces </li></ul><ul><li>Assist some cells in attaching to other cells or in eluding antimicrobial drugs </li></ul><ul><li>Not present in animal cells, so can target cell wall of bacteria with antibiotics </li></ul><ul><li>Bacteria and archaea have different cell wall chemistry </li></ul>
  30. 30. Prokaryotic Cell Wall <ul><li>Bacterial Cell Walls </li></ul><ul><ul><li>Most have cell wall composed of peptidoglycan </li></ul></ul><ul><ul><li>Peptidoglycan is composed of sugars, NAG, and NAM </li></ul></ul><ul><ul><li>Chains of NAG and NAM attached to other chains by tetrapeptide crossbridges </li></ul></ul><ul><ul><ul><li>Bridges may be covalently bonded to one another </li></ul></ul></ul><ul><ul><ul><li>Bridges may be held together by short connecting chains of amino acids </li></ul></ul></ul><ul><ul><li>Scientists describe two basic types of bacterial cell walls: Gram-positive and Gram-negative </li></ul></ul>
  31. 31. External Structures of Prokaryotic Cells [INSERT FIGURE 3.12]
  32. 32. External Structures of Prokaryotic Cells [INSERT FIGURE 3.13]
  33. 33. Prokaryotic Cell Walls <ul><li>Bacterial Cell Walls </li></ul><ul><ul><li>Gram-positive cell walls </li></ul></ul><ul><ul><ul><li>Relatively thick layer of peptidoglycan </li></ul></ul></ul><ul><ul><ul><li>Contain unique polyalcohols called teichoic acids </li></ul></ul></ul><ul><ul><ul><ul><li>Some covalently linked to lipids, forming lipoteichoic acids that anchor peptidoglycan to cell membrane </li></ul></ul></ul></ul><ul><ul><ul><li>Retain crystal violet dye in Gram staining procedure; so appear purple </li></ul></ul></ul><ul><ul><ul><li>Up to 60% mycolic acid in acid-fast bacteria helps cells survive desiccation </li></ul></ul></ul>
  34. 34. Prokaryotic Cell Walls [INSERT FIGURE 3.14a]
  35. 35. Prokaryotic Cell Walls <ul><li>Bacterial Cell Walls </li></ul><ul><ul><li>Gram-negative cell walls </li></ul></ul><ul><ul><ul><li>Have only a thin layer of peptidoglycan </li></ul></ul></ul><ul><ul><ul><li>Bilayer membrane outside the peptidoglycan contains phospholipids, proteins, and lipopolysaccharide (LPS) </li></ul></ul></ul><ul><ul><ul><li>May be impediment to the treatment of disease </li></ul></ul></ul><ul><ul><ul><li>Appear pink following Gram staining procedure </li></ul></ul></ul>
  36. 36. Prokaryotic Cell Walls [INSERT FIGURE 3.14b]
  37. 37. Prokaryotic Cell Walls <ul><li>Archaeal Cell Walls </li></ul><ul><ul><li>Do not have peptidoglycan </li></ul></ul><ul><ul><li>Contains variety of specialized polysaccharides and proteins </li></ul></ul><ul><ul><li>Gram-positive archaea stain purple </li></ul></ul><ul><ul><li>Gram-negative archaea stain pink </li></ul></ul>
  38. 38. Prokaryotic Cytoplasmic Membranes <ul><li>Structure </li></ul><ul><ul><li>Referred to as phospholipid bilayer; composed of lipids and associated proteins </li></ul></ul><ul><ul><li>Approximately half composed of proteins that act as recognition proteins, enzymes, receptors, carriers, or channels </li></ul></ul><ul><ul><ul><li>Integral proteins </li></ul></ul></ul><ul><ul><ul><li>Peripheral proteins </li></ul></ul></ul><ul><ul><ul><li>Glycoproteins </li></ul></ul></ul><ul><ul><li>Fluid mosaic model describes current understanding of membrane structure </li></ul></ul>
  39. 39. Prokaryotic Cytoplasmic Membranes [INSERT FIGURE 3.15]
  40. 40. Prokaryotic Cytoplasmic Membranes <ul><li>Function </li></ul><ul><ul><li>Energy storage </li></ul></ul><ul><ul><li>Harvest light energy in photosynthetic prokaryotes </li></ul></ul><ul><ul><li>Selectively permeable </li></ul></ul><ul><ul><li>Naturally impermeable to most substances </li></ul></ul><ul><ul><li>Proteins allow substances to cross membrane </li></ul></ul><ul><ul><ul><li>Occurs by passive or active processes </li></ul></ul></ul><ul><ul><li>Maintain concentration and electrical gradient </li></ul></ul><ul><ul><ul><li>Chemicals concentrated on one side of the membrane or the other </li></ul></ul></ul><ul><ul><ul><li>Voltage exists across the membrane </li></ul></ul></ul>
  41. 41. Prokaryotic Cytoplasmic Membranes [INSERT FIGURE 3.16]
  42. 42. Prokaryotic Cytoplasmic Membranes <ul><li>Function </li></ul><ul><ul><li>Passive processes </li></ul></ul><ul><ul><ul><li>Diffusion </li></ul></ul></ul><ul><ul><ul><li>Facilitated diffusion </li></ul></ul></ul><ul><ul><ul><li>Osmosis </li></ul></ul></ul><ul><ul><ul><ul><li>Isotonic solution </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Hypertonic solution </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Hypotonic solution </li></ul></ul></ul></ul>
  43. 43. Prokaryotic Cytoplasmic Membranes [INSERT FIGURE 3.17]
  44. 44. Prokaryotic Cytoplasmic Membranes [INSERT FIGURE 3.18]
  45. 45. Prokaryotic Cytoplasmic Membranes [INSERT FIGURE 3.19]
  46. 46. Prokaryotic Cytoplasmic Membranes <ul><li>Function </li></ul><ul><ul><li>Active processes </li></ul></ul><ul><ul><ul><li>Active transport </li></ul></ul></ul><ul><ul><ul><ul><li>Utilize permease proteins and expend ATP </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Uniport </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Antiport </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Symport </li></ul></ul></ul></ul><ul><ul><li>Group translocation </li></ul></ul><ul><ul><ul><li>Substance chemically modified during transport </li></ul></ul></ul>
  47. 47. Prokaryotic Cytoplasmic Membranes [INSERT FIGURE 3.20]
  48. 48. Prokaryotic Cytoplasmic Membranes Animation: Active Transport Overview
  49. 49. Prokaryotic Cytoplasmic Membranes Animation: Active Transport Types
  50. 50. Prokaryotic Cytoplasmic Membranes [INSERT FIGURE 3.21]
  51. 51. Prokaryotic Cytoplasmic Membranes [INSERT TABLE 3.2]
  52. 52. Cytoplasm of Prokaryotes <ul><li>Cytosol – liquid portion of cytoplasm </li></ul><ul><li>Inclusions – may include reserve deposits of chemicals </li></ul><ul><li>Endospores – unique structures produced by some bacteria that are a defensive strategy against unfavorable conditions </li></ul>
  53. 53. Cytoplasm of Prokaryotes
  54. 54. Cytoplasm of Prokaryotes <ul><li>Nonmembranous Organelles </li></ul><ul><ul><li>Ribosomes – sites of protein synthesis </li></ul></ul><ul><ul><li>Cytoskeleton – plays a role in forming the cell’s basic shape </li></ul></ul>
  55. 55. Cytoplasm of Prokaryotes [INSERT FIGURE 3.23]
  56. 56. External Structure of Eukaryotic Cells <ul><li>Glycocalyces </li></ul><ul><ul><li>Never as organized as prokaryotic capsules </li></ul></ul><ul><ul><li>Help anchor animal cells to each other </li></ul></ul><ul><ul><li>Strengthen cell surface </li></ul></ul><ul><ul><li>Provide protection against dehydration </li></ul></ul><ul><ul><li>Function in cell-to-cell recognition and communication </li></ul></ul>
  57. 57. Eukaryotic Cell Walls & Cytoplasmic Membranes <ul><li>Fungi, algae, plants, and some protozoa have cell walls but no glycocalyx </li></ul><ul><li>Composed of various polysaccharides </li></ul><ul><ul><li>Cellulose found in plant cell walls </li></ul></ul><ul><ul><li>Fungal cell walls composed of cellulose, chitin, and/or glucomannan </li></ul></ul><ul><ul><li>Algal cell walls composed of cellulose, proteins, agar, carrageenan, silicates, algin, calcium carbonate, or a combination of these </li></ul></ul>
  58. 58. Eukaryotic Cell Walls & Cytoplasmic Membranes [INSERT FIGURE 3.24]
  59. 59. Eukaryotic Cell Walls & Cytoplasmic Membranes <ul><li>All eukaryotic cells have cytoplasmic membrane </li></ul><ul><li>Are a fluid mosaic of phospholipids and proteins </li></ul><ul><li>Contain steroid lipids to help maintain fluidity </li></ul><ul><li>Contain regions of lipids and proteins called membrane rafts </li></ul><ul><li>Control movement into and out of cell </li></ul><ul><ul><li>Use diffusion, facilitated diffusion, osmosis, and active transport </li></ul></ul><ul><ul><li>Perform endocytosis; phagocytosis if solid substance and pinocytosis if liquid substance </li></ul></ul><ul><ul><li>Exocytosis enables substances to be exported from cell </li></ul></ul>
  60. 60. Eukaryotic Cell Walls & Cytoplasmic Membranes [INSERT FIGURE 3.25]
  61. 61. Eukaryotic Cell Walls & Cytoplasmic Membranes [INSERT TABLE 3.3]
  62. 62. Eukaryotic Cell Walls & Cytoplasmic Membranes [INSERT FIGURE 3.26]
  63. 63. Cytoplasm of Eukaryotes
  64. 64. Cytoplasm of Eukaryotes <ul><li>Flagella </li></ul><ul><ul><li>Structure and arrangement </li></ul></ul><ul><ul><ul><li>Shaft composed of tubulin arranged to form microtubules </li></ul></ul></ul><ul><ul><ul><li>“ 9 + 2” arrangement of microtubules in all flagellated eukaryotes </li></ul></ul></ul><ul><ul><ul><li>Filaments anchored to cell by basal body; no hook </li></ul></ul></ul><ul><ul><ul><li>Basal body has “9 + 0” arrangement of microtubules </li></ul></ul></ul><ul><ul><ul><li>May be single or multiple; generally found at one pole of cell </li></ul></ul></ul>
  65. 65. Cytoplasm of Eukaryotes <ul><li>Flagella </li></ul><ul><ul><li>Function </li></ul></ul><ul><ul><ul><li>Do not rotate, but undulate rhythmically </li></ul></ul></ul>
  66. 66. Cytoplasm of Eukaryotes [INSERT FIGURE 3.28a & b]
  67. 67. Cytoplasm of Eukaryotes <ul><li>Cilia </li></ul><ul><ul><li>Shorter and more numerous than flagella </li></ul></ul><ul><ul><li>Composed of tubulin in “9 + 2” and “9 + 0” arrangements </li></ul></ul><ul><ul><li>Coordinated beating propels cells through their environment </li></ul></ul><ul><ul><li>Also used to move substances past the surface of the cell </li></ul></ul>
  68. 68. Cytoplasm of Eukaryotes [INSERT FIGURE 3.27c]
  69. 69. Cytoplasm of Eukaryotes <ul><li>Other Nonmembranous Organelles </li></ul><ul><ul><li>Ribosomes </li></ul></ul><ul><ul><ul><li>Larger than prokaryotic ribosomes (80S versus 70S) </li></ul></ul></ul><ul><ul><ul><li>Composed of 60S and 40S subunits </li></ul></ul></ul><ul><ul><li>Cytoskeleton </li></ul></ul><ul><ul><ul><li>Extensive </li></ul></ul></ul><ul><ul><ul><li>Functions </li></ul></ul></ul><ul><ul><ul><ul><li>Anchors organelles </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Cytoplasmic streaming and movement of organelles </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Movement during endocytosis and amoeboid action </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Produces basic shape of the cell </li></ul></ul></ul></ul><ul><ul><ul><li>Made up of tubulin microtubules, actin microfilaments, and intermediate filaments </li></ul></ul></ul>
  70. 70. Cytoplasm of Eukaryotes [INSERT FIGURE 3.29]
  71. 71. Cytoplasm of Eukaryotes <ul><li>Other Nonmembranous Organelles </li></ul><ul><ul><li>Centrioles and centrosome </li></ul></ul><ul><ul><ul><li>Centrioles play a role in mitosis, cytokinesis, and in formation of flagella and cilia </li></ul></ul></ul><ul><ul><ul><li>Centrioles composed of “9 + 0” arrangement of microtubules </li></ul></ul></ul><ul><ul><ul><li>Centrosome is region of cytoplasm where centrioles are found </li></ul></ul></ul>
  72. 72. Cytoplasm of Eukaryotes [INSERT FIGURE 3.30]
  73. 73. Cytoplasm of Eukaryotes <ul><li>Membranous Organelles </li></ul><ul><ul><li>Nucleus </li></ul></ul><ul><ul><ul><li>Often largest organelle in cell </li></ul></ul></ul><ul><ul><ul><li>Contains most of the cell’s DNA </li></ul></ul></ul><ul><ul><ul><li>Semi-liquid portion called nucleoplasm </li></ul></ul></ul><ul><ul><ul><li>One or more nucleoli present in nucleoplasm; RNA synthesized in nucleoli </li></ul></ul></ul><ul><ul><ul><li>Nucleoplasm contains chromatin – masses of DNA associated with histones </li></ul></ul></ul><ul><ul><ul><li>Surrounded by nuclear envelope – double membrane composed of two phospholipid bilayers </li></ul></ul></ul><ul><ul><ul><li>Nuclear envelope contains nuclear pores </li></ul></ul></ul>
  74. 74. Cytoplasm of Eukaryotes [INSERT FIGURE 3.31]
  75. 75. Cytoplasm of Eukaryotes <ul><li>Membranous Organelles </li></ul><ul><ul><li>Endoplasmic reticulum </li></ul></ul><ul><ul><ul><li>Netlike arrangement of flattened, hollow tubules continuous with nuclear envelope </li></ul></ul></ul><ul><ul><ul><li>Functions as transport system </li></ul></ul></ul><ul><ul><ul><li>Two forms </li></ul></ul></ul><ul><ul><ul><ul><li>Smooth endoplasmic reticulum (SER) – plays role in lipid synthesis </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Rough endoplasmic reticulum (RER) – ribosomes attached to its outer surface; transports proteins produced by ribosomes </li></ul></ul></ul></ul>
  76. 76. Cytoplasm of Eukaryotes [INSERT FIGURE 3.32]
  77. 77. Cytoplasm of Eukaryotes <ul><li>Membranous Organelles </li></ul><ul><ul><li>Golgi body </li></ul></ul><ul><ul><ul><li>Receives, processes, and packages large molecules for export from cell </li></ul></ul></ul><ul><ul><ul><li>Packages molecules in secretory vesicles that fuse with cytoplasmic membrane </li></ul></ul></ul><ul><ul><ul><li>Composed of flattened hollow sacs surrounded by phospholipid bilayer </li></ul></ul></ul><ul><ul><ul><li>Not in all eukaryotic cells </li></ul></ul></ul>
  78. 78. Cytoplasm of Eukaryotes [INSERT FIGURE 3.33]
  79. 79. Cytoplasm of Eukaryotes <ul><li>Membranous Organelles </li></ul><ul><ul><li>Lysosomes, peroxisomes,vacuoles, and vesicles </li></ul></ul><ul><ul><ul><li>Store and transfer chemicals within cells </li></ul></ul></ul><ul><ul><ul><li>May store nutrients in cell </li></ul></ul></ul><ul><ul><ul><li>Lysosomes contain catabolic enzymes </li></ul></ul></ul><ul><ul><ul><li>Peroxisomes contain enzymes that degrade poisonous wastes </li></ul></ul></ul>
  80. 80. Cytoplasm of Eukaryotes [INSERT FIGURE 3.34]
  81. 81. Cytoplasm of Eukaryotes [INSERT FIGURE 3.35]
  82. 82. Cytoplasm of Eukaryotes <ul><li>Membranous Organelles </li></ul><ul><ul><li>Mitochondria </li></ul></ul><ul><ul><ul><li>Have two membranes composed of phospholipid bilayer </li></ul></ul></ul><ul><ul><ul><li>Produce most of cell’s ATP </li></ul></ul></ul><ul><ul><ul><li>Interior matrix contains 70S ribosomes and circular molecule of DNA </li></ul></ul></ul>
  83. 83. Cytoplasm of Eukaryotes [INSERT FIGURE 3.36]
  84. 84. Cytoplasm of Eukaryotes <ul><li>Membranous Organelles </li></ul><ul><ul><li>Chloroplasts </li></ul></ul><ul><ul><ul><li>Light-harvesting structures found in photosynthetic eukaryotes </li></ul></ul></ul><ul><ul><ul><li>Have two phospholipid bilayer membranes and DNA </li></ul></ul></ul><ul><ul><ul><li>Have 70S ribosomes </li></ul></ul></ul>
  85. 85. Cytoplasm of Eukaryotes [INSERT FIGURE 3.37]
  86. 86. Cytoplasm of Eukaryotes [INSERT TABLE 3.4]
  87. 87. Cytoplasm of Eukaryotes <ul><li>Endosymbiotic Theory </li></ul><ul><ul><li>Eukaryotes formed from union of small aerobic prokaryotes with larger anaerobic prokaryotes </li></ul></ul><ul><ul><li>smaller prokaryotes became internal parasites </li></ul></ul><ul><ul><ul><li>Parasites lost ability to exist independently; retained portion of DNA, ribosomes, and cytoplasmic membranes </li></ul></ul></ul><ul><ul><ul><li>Larger cell became dependent on parasites for aerobic ATP production </li></ul></ul></ul><ul><ul><ul><li>Aerobic prokaryotes evolved into mitochondria </li></ul></ul></ul><ul><ul><ul><li>Similar scenario for origin of chloroplasts </li></ul></ul></ul><ul><ul><li>Not universally accepted </li></ul></ul>
  88. 88. Cytoplasm of Eukaryotes [INSERT TABLE 3.5]

×