Bio Chapter 7

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Bio Chapter 7
2012-10-05 12:27:25

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  1. Selective Permeability
    • Allo some substance to cross plasma membrane more easily
    • Polar substance like glucose and water pass slower than nonpolar  like oxygen ,co2 and hydrogencarbon
  2. Amphipathic
    • have both hydrophililic region and a hydrophobic region.
    • Ex: phopholipid and other membranes
  3. Fluid Mosaic Model
    Model of plasma membrane

    Phospholipid bilayer heads, hydrophobic tail inside, Hyrophoci region between the heads
  4. Integral proteins
    membrane prteins  that penetratr the hydrophobic interior of lipid bilaye
  5. Peripheral Proteins
    • no embedded in the lipid bilayer
    • loosely bound to the surface of the membrane
    • exposed to part of intergral proteins
  6. Functions of plasma membrane proteins
    • Transport
    • Enzymatic activity
    • Signal transduction
    • cell cell recognition
    • intercellular joining
    • attachment to the cytoskeleton and ECM
  7. Transport Protein
    channel protein, hydrophilic channel that certain molecukes use it as tunnel through the membrane
  8. Diffusion
    • the movement of molecules of any substance so that they spread out evenly into avaliable space
    • concentration gradient - substance diffuse down
    • no work is needed
    • passive transport - no energy
    • active transport - yses energy
  9. Osmosis
    the diffusion of free water across a selectively permeable membrane
  10. tonicity/isotonic/hypertonic
    • the ability of a surrounding solution to cause a cell to gain or lose water
    • isotonic - same , no net movement of the water
    • hypertonic - cell lose water, shrivel, and probably die
    • hypotonic into cell - water enter cell fast make it swell and lyse(burst)
  11. plasmolysis
    plant cell place in a hypertonic environment -> CELL SHRIVELS and lose water to surrounding -> die
  12. Membrane potential
    voltage across a membrane
  13. cotransport
    single ATP powered pump that transports a specific solutes in a mechanism called  a cotransport.
  14. exocytosis
    cell secretes certain biological molecules by the fusion of vesicles with the plasma membrane
  15. endocytosis
    the cell takes in biological molecules and particulate matter by forming new vesicles from the plasm membrane