Biology Chapter 7

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Biology Chapter 7
2013-10-28 19:43:23

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  1. selective permeability
    when a plasma membrane allows some substances to cross it more easily than others
  2. amphipathic (amphiphilic)
    both hydrophobic and hydrophilic regions (phospholipids are this)
  3. transmembrane proteins
    integral proteins that span the membrane
  4. transport proteins (channel proteins)
    allow passage of hydrophilic substances across the membrane
  5. glycoproteins
    formed by carbohydrates being covalently bonded to proteins
  6. aquaporins
    channel proteins that facilitate the passage of water
  7. diffusion
    the tendency for molecules to spread out evenly into the available space
  8. concentration gradient
  9. passive transport
    diffusion of a substance across a membrane (no energy investment)
  10. osmosis
    diffusion of water across a selectively permeable membrane
  11. isotonic
    solute concentration of the environment is the same as that inside the cell
  12. hypertonic
    solute concentration of the environment is greater than that inside the cell
  13. hypotonic
    solute concentration of the environment is less than that inside the cell
  14. plasmolysis
    when in a hypertonic environment plant cells lose water and the membrane pulls away from the wall (this is usually lethal)
  15. active transport
    moving a substance up a concentration gradient
  16. proton pump
    active transport protein in a cell membrane that uses ATP to transport hydrogen ions out of a cell against their concentration gradient, generating a membrane potential in the process
  17. exocytosis
    cellular secretion of biological molecules by the fusion of vesicles containing them with the plasma membrane
  18. endocytosis
    cellular uptake of biological molecules and particulate matter via formation of vesicles from the plasma membrane
  19. receptor-mediated endocytosis
    movement of specific molecules into a cell by the inward budding of vesicles containing proteins with receptor cites specific to the molecules being taken in; enables a cell to aquire bulk quantities of specific substances