Chapter 7

1,117 views

Published on

Published in: Technology, Business
0 Comments
1 Like
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
1,117
On SlideShare
0
From Embeds
0
Number of Embeds
4
Actions
Shares
0
Downloads
37
Comments
0
Likes
1
Embeds 0
No embeds

No notes for slide

Chapter 7

  1. 1. Chapter 7<br />Membrane structure and function<br />
  2. 2. overview<br />
  3. 3. Fluid Mosaics<br />Concept 7.1<br />
  4. 4. Phospholipids are amphipathic:<br />Two regions.<br />
  5. 5. Fluid mosaic model: phospholipids + various proteins embedded<br />
  6. 6. Freeze-fracture supported theory.<br />
  7. 7. Fluidity of membranes<br />Movement<br />Drifting<br />Flip-flop<br />
  8. 8.
  9. 9. Temperature and type of fatty acids affect fluidity.<br />
  10. 10. Cholesterol molecules help maintain fluidity.<br />
  11. 11. Membrane proteins<br />Variety of proteins.<br />Determine most of membrane’s specific functions.<br />
  12. 12.
  13. 13.
  14. 14. Six major functions (1-3)<br />
  15. 15. Six major functions (4-6)<br />
  16. 16. Sidedness of membranes<br />Membranes have distinct inside and outside determined when build by ER and Golgi<br />
  17. 17. Selective Permeability<br />Concept 7.2<br />
  18. 18. Permeability<br />Material exchange controlled by membrane.<br />Hydrophobic (nonpolar) dissolve in lipid bilayer and pass through rapidly.<br />Polar molecules (sugars) do not cross easily.<br />
  19. 19. Transport Proteins<br />Allow passage of hydrophilic substances.<br />Channel proteins – hydrophilic channel used as a tunnel.<br />Aquaporins– facilitate passage of water.<br />Carrier proteins – change shape to move (specific for substance it moves.)<br />
  20. 20. Passive Transport<br />Concept 7.2<br />
  21. 21.
  22. 22. Down concentration gradient.<br />
  23. 23. Osmosis<br />Diffusion of water.<br />Moves from area of lower solute concentration to an area of higher solute concentration.<br />
  24. 24.
  25. 25. Tonicity<br />The ability of a solution to cause a cell to gain or lose water.<br />
  26. 26. Tonicity<br />Isotonic solution: Solute concentration is the same as that inside the cell; no net water movement across the plasma membrane<br />Hypertonic solution: Solute concentration is greater than that inside the cell; cell loses water<br />Hypotonic solution: Solute concentration is less than that inside the cell; cell gains water<br />
  27. 27.
  28. 28. Osmoregulation, the control of water balance<br />
  29. 29. Facilitated diffusion.<br />
  30. 30. Active Transport<br />Concept 7.4<br />
  31. 31. Active transport<br />Needs energy.<br />Sodium-potassium pump is an example.<br />
  32. 32. Fig. 7-16-1<br />EXTRACELLULAR<br />FLUID <br />[Na+] high <br />[K+] low <br />Na+<br />Na+<br />[Na+] low<br />Na+<br />CYTOPLASM <br />[K+] high <br />1 <br />Cytoplasmic Na+ binds to<br />the sodium-potassium pump.<br />
  33. 33. Fig. 7-16-2<br />Na+<br />Na+<br />Na+<br />ATP <br />P <br />ADP <br />Na+ binding stimulates<br />phosphorylation by ATP. <br />2<br />
  34. 34. Fig. 7-16-3<br />Na+<br />Na+<br />Na+<br />P <br /> Phosphorylation causes<br />the protein to change its<br />shape. Na+ is expelled to<br />the outside. <br />3<br />
  35. 35. Fig. 7-16-4<br />K+<br />K+<br />P<br />P<br /> K+ binds on the<br />extracellular side and<br />triggers release of the<br />phosphate group. <br />4<br />
  36. 36. Fig. 7-16-5<br />K+<br />K+<br /> Loss of the phosphate<br />restores the protein’s original<br />shape. <br />5<br />
  37. 37. Fig. 7-16-6<br />K+<br />K+<br /> K+ is released, and the<br />cycle repeats. <br />6 <br />
  38. 38.
  39. 39. Membrane Potential<br />Voltage difference of positive and negative ions.<br />Electrochemical gradient.<br />
  40. 40. Electrogenic pump: generates voltage across membrane.<br />
  41. 41. Cotransport<br />
  42. 42. Bulk transport<br />Concept 7.5<br />
  43. 43. Exocytosis<br />Large release of materials in a transport vesicle.<br />
  44. 44. endocytosis<br />Taking in large molecules by forming vesicles.<br />Three Types:<br />Phagocytosis<br />Pinocytosis<br />Receptor-mediated endocytosis.<br />

×