kati 7

  1. how thick is the plasma membrane?
  2. what is a special characteristic of the plasma membrane and that does it mean?
    -selective permeability-allows some substance to cross it more easily than others
  3. what are the main ingredients of membranes?
    lipis and proteins
  4. what are the most abundent lipids in membranes?
  5. what is an amphipathic molecule?
    has both a hydrophilic region and a hydrophobic region
  6. fluid mosaic model
    • -various proteins embedded in or attached to a double layer (bilayer) of phospholipids.
    • -lipis (phospholipids) has cholesterol lipids stuck in between
    • -proteins
    • -carbohydrate (outside)-establish identity foe cell
    • -cholesterol helps stabilize lipid bilayer
  7. integral proteins
    inbetween lipid bilayer
  8. peripheral proteins
    • on one side or other,
    • -often to expose parts of integral protein
  9. glycolipids
    • sugar units covalently bonded to lipids
    • -on extracellular side of the plasma membrane use them to distinguish one cell from another
  10. permeability of lipid bilayer
    only hydrophobic and slightly charged molecules are permeable
  11. transport proteins
    a protein that spans the membrane may provide a hydrophilic channel across the membrane that is selective for a particular solute
  12. aquaporins
    • transport protein for water
    • -the passage of water molecles through the membrane in certain cells is greatly facilitated by channel proteins
  13. passive transport
    • -no energy needed
    • -diffusion of a substance across a membrane with no energy investement
  14. carrier proteins
    • holds on to their passengers and change shape in a way that shuttles them across the membrane.
    • -made for only a certain kind of substance that it will shuttle
  15. diffusion
    the movement of molecules of any substance so that they spread out evenly into the available space
  16. concentration gradient
    the region along which the density of a chemical substance decreases
  17. osmosis
    diffusion of water molecules along semipermeable membrane
  18. tonicity
    what are the kinds?
    • the ability of a solution to cause a cell to lose or gain water.
    • (remember opposited, goes to solute)
    • -hypertonic-shriveled, plasmolyzed
    • -isotonic-normal, flaccid
    • hypotonic-lysed, turgid (normal)
  19. facilitated diffusion
    polar molecules and ions imoeaded by the lipid bilayer of the membrane diffuse passively with the help of transport proteins that span the membrane
  20. active transport
    uses energy to move solutes against their gradients
  21. cotransport
    a single ATP powereed pump that transports a specific solute can indirectly drive the active transport of several other solutes in a solution.
Card Set
kati 7
kati 7