A Tour of The Cell


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A Tour of The Cell

  1. 1. Chapter 6 A Tour of the Cell
  2. 2. Figure 6-01
  3. 3. LE 6-2 Measurements 1 centimeter (cm) = 10 –2 meter (m) = 0.4 inch 1 millimeter (mm) = 10 –3 m 1 micrometer (µm) = 10 –3 mm = 10 –6 m 1 nanometer (nm) = 10 –3 µm = 10 –9 m 10 m 1 m Human height Length of some nerve and muscle cells Chicken egg 0.1 m 1 cm Frog egg 1 mm 100 µm Most plant and animal cells 10 µm Nucleus 1 µm Most bacteria Mitochondrion Smallest bacteria Viruses 100 nm 10 nm Ribosomes Proteins Lipids 1 nm Small molecules Atoms 0.1 nm Unaided eye Light microscope Electron microscope Activity: Metric Review
  4. 4. LE 6-3a Brightfield (unstained specimen) 50 µm Brightfield (stained specimen) Phase-contrast
  5. 5. LE 6-3b 50 µm 50 µm Confocal Differential- interference- contrast (Nomarski) Fluorescence
  6. 6. LE 6-4 1 µm 1 µm Scanning electron microscopy (SEM) Cilia Longitudinal section of cilium Transmission electron microscopy (TEM) Cross section of cilium
  7. 7. LE 6-5a Homogenization Homogenate Tissue cells Differential centrifugation
  8. 8. LE 6-5b Pellet rich in nuclei and cellular debris Pellet rich in mitochondria (and chloro- plasts if cells are from a plant) Pellet rich in “ microsomes” (pieces of plasma membranes and cells’ internal membranes) Pellet rich in ribosomes 150,000 g 3 hr 80,000 g 60 min 20,000 g 20 min 1000 g (1000 times the force of gravity) 10 min Supernatant poured into next tube
  9. 9. LE 6-6 A typical rod-shaped bacterium A thin section through the bacterium Bacillus coagulans (TEM) 0.5 µm Pili Nucleoid Ribosomes Plasma membrane Cell wall Capsule Flagella Bacterial chromosome Activity: Prokaryotic Cells
  10. 10. LE 6-7 Total surface area (height x width x number of sides x number of boxes) 6 125 125 150 750 1 1 1 5 1.2 6 6 Total volume (height x width x length X number of boxes) Surface-to-volume ratio (surface area  volume) Surface area increases while Total volume remains constant
  11. 11. LE 6-8 Hydrophilic region Hydrophobic region Carbohydrate side chain Structure of the plasma membrane Hydrophilic region Phospholipid Proteins Outside of cell Inside of cell 0.1 µm TEM of a plasma membrane
  12. 12. LE 6-9a Flagellum Centrosome CYTOSKELETON Microfilaments Intermediate filaments Microtubules Peroxisome Microvilli ENDOPLASMIC RETICULUM (ER Rough ER Smooth ER Mitochondrion Lysosome Golgi apparatus Ribosomes: Plasma membrane Nuclear envelope NUCLEUS In animal cells but not plant cells: Lysosomes Centrioles Flagella (in some plant sperm) Nucleolus Chromatin
  13. 13. LE 6-9b Rough endoplasmic reticulum In plant cells but not animal cells: Chloroplasts Central vacuole and tonoplast Cell wall Plasmodesmata Smooth endoplasmic reticulum Ribosomes (small brown dots) Central vacuole Microfilaments Intermediate filaments Microtubules CYTOSKELETON Chloroplast Plasmodesmata Wall of adjacent cell Cell wall Nuclear envelope Nucleolus Chromatin NUCLEUS Centrosome Golgi apparatus Mitochondrion Peroxisome Plasma membrane Activity: Prokaryotic and Eukaryotic Cells Activity: Plant & Animal Cells
  14. 14. LE 6-10 Close-up of nuclear envelope Nucleus Nucleolus Chromatin Nuclear envelope: Inner membrane Outer membrane Nuclear pore Pore complex Ribosome Pore complexes (TEM) Nuclear lamina (TEM) 1 µm Rough ER Nucleus 1 µm 0.25 µm Surface of nuclear envelope Activity: Nucleus & Ribosomes
  15. 15. LE 6-11 Ribosomes 0.5 µm ER Cytosol Endoplasmic reticulum (ER) Free ribosomes Bound ribosomes Large subunit Small subunit Diagram of a ribosome TEM showing ER and ribosomes
  16. 16. LE 6-16-1 Nuclear envelope Nucleus Rough ER Smooth ER
  17. 17. LE 6-16-2 Nuclear envelope Nucleus Rough ER Smooth ER Transport vesicle cis Golgi trans Golgi
  18. 18. LE 6-16-3 Nuclear envelope Nucleus Rough ER Smooth ER Transport vesicle cis Golgi trans Golgi Plasma membrane Activity: Endomembrane System
  19. 19. LE 6-12 Ribosomes Smooth ER Rough ER ER lumen Cisternae Transport vesicle Smooth ER Rough ER Transitional ER 200 nm Nuclear envelope
  20. 20. LE 6-13 trans face (“shipping” side of Golgi apparatus) TEM of Golgi apparatus 0.1 µm Golgi apparatus cis face (“receiving” side of Golgi apparatus) Vesicles coalesce to form new cis Golgi cisternae Vesicles also transport certain proteins back to ER Vesicles move from ER to Golgi Vesicles transport specific proteins backward to newer Golgi cisternae Cisternal maturation: Golgi cisternae move in a cis - to- trans direction Vesicles form and leave Golgi, carrying specific proteins to other locations or to the plasma mem- brane for secretion Cisternae
  21. 21. LE 6-14a Phagocytosis: lysosome digesting food 1 µm Plasma membrane Food vacuole Lysosome Nucleus Digestive enzymes Digestion Lysosome Lysosome contains active hydrolytic enzymes Food vacuole fuses with lysosome Hydrolytic enzymes digest food particles
  22. 22. LE 6-14b Autophagy: lysosome breaking down damaged organelle 1 µm Vesicle containing damaged mitochondrion Mitochondrion fragment Lysosome containing two damaged organelles Digestion Lysosome Lysosome fuses with vesicle containing damaged organelle Peroxisome fragment Hydrolytic enzymes digest organelle components
  23. 23. LE 6-15 5 µm Central vacuole Cytosol Tonoplast Central vacuole Nucleus Cell wall Chloroplast
  24. 24. LE 6-17 Mitochondrion Intermembrane space Outer membrane Inner membrane Cristae Matrix 100 nm Mitochondrial DNA Free ribosomes in the mitochondrial matrix
  25. 25. LE 6-18 Chloroplast Chloroplast DNA Ribosomes Stroma Inner and outer membranes Granum Thylakoid 1 µm Activity: Build a Chloroplast and a Mitochondion
  26. 26. LE 6-19 Chloroplast Peroxisome Mitochondrion 1 µm
  27. 27. Cytoskeleton <ul><li>Three main types: </li></ul><ul><ul><li>Microtubules </li></ul></ul><ul><ul><li>Microfilaments </li></ul></ul><ul><ul><li>Intermediate Filaments </li></ul></ul>
  28. 28. Table 6-1a
  29. 29. LE 6-20 Microtubule Microfilaments 0.25 µm
  30. 30. LE 6-21a Vesicle Receptor for motor protein Microtubule of cytoskeleton Motor protein (ATP powered) ATP
  31. 31. LE 6-21b 0.25 µm Microtubule Vesicles
  32. 32. LE 6-22 0.25 µm Microtubule Centrosome Centrioles Longitudinal section of one centriole Microtubules Cross section of the other centriole
  33. 33. LE 6-23b 15 µm Direction of organism’s movement Motion of cilia Direction of active stroke Direction of recovery stroke
  34. 34. LE 6-23a 5 µm Direction of swimming Motion of flagella
  35. 35. LE 6-24 0.5 µm Microtubules Plasma membrane Basal body Plasma membrane 0.1 µm Cross section of basal body Triplet Outer microtubule doublet 0.1 µm Dynein arms Central microtubule Cross-linking proteins inside outer doublets Radial spoke Activity: Cilia & Flagella
  36. 36. LE 6-25a Dynein “walking” Microtubule doublets ATP Dynein arm
  37. 37. LE 6-25b Wavelike motion Cross-linking proteins inside outer doublets ATP Anchorage in cell Effect of cross-linking proteins
  38. 38. Table 6-1b
  39. 39. LE 6-26 Microfilaments (actin filaments) Microvillus Plasma membrane Intermediate filaments 0.25 µm
  40. 40. LE 6-27a Muscle cell Actin filament Myosin filament Myosin arm Myosin motors in muscle cell contraction
  41. 41. LE 6-27b Cortex (outer cytoplasm): gel with actin network Amoeboid movement Inner cytoplasm: sol with actin subunits Extending pseudopodium
  42. 42. LE 6-27c Nonmoving cytoplasm (gel) Cytoplasmic streaming in plant cells Chloroplast Streaming cytoplasm (sol) Cell wall Parallel actin filaments Vacuole
  43. 43. Table 6-1c
  44. 44. LE 6-10 Close-up of nuclear envelope Nucleus Nucleolus Chromatin Nuclear envelope: Inner membrane Outer membrane Nuclear pore Pore complex Ribosome Pore complexes (TEM) Nuclear lamina (TEM) 1 µm Rough ER Nucleus 1 µm 0.25 µm Surface of nuclear envelope
  45. 45. LE 6-28 Central vacuole of cell Plasma membrane Secondary cell wall Primary cell wall Middle lamella 1 µm Central vacuole of cell Central vacuole Cytosol Plasma membrane Plant cell walls Plasmodesmata Plant Cell Walls
  46. 46. LE 6-29a EXTRACELLULAR FLUID Proteoglycan complex Collagen fiber Fibronectin Integrin Micro- filaments CYTOPLASM Plasma membrane Animal ECM (Extra Cellular Matrix) -or- glycoprotein
  47. 47. LE 6-29b Polysaccharide molecule Carbo- hydrates Core protein Proteoglycan molecule Proteoglycan complex
  48. 48. LE 6-30 Interior of cell Interior of cell 0.5 µm Plasmodesmata Plasma membranes Cell walls
  49. 49. LE 6-31 Tight junctions prevent fluid from moving across a layer of cells Tight junction 0.5 µm 1 µm 0.1 µm Gap junction Extracellular matrix Space between cells Plasma membranes of adjacent cells Intermediate filaments Tight junction Desmosome Gap junctions Activity: cellular junctions