membrane transport, chapter 3

  1. plasma membrane is.....
    selectively permeable
  2. movement of substances from one area to depends on
    concentration gradient
  3. Passive transport:
    requires NO ATP to move down concentration gradient--Passive processes - substances move across cell membranes without the input of any energy; uses the kinetic energy of individual molecules or ions
  4. Active transport:
    requires ATP to move against a concentration gradient--Active processes - a cell uses energy, primarily from the breakdown of ATP, to move a substance across the membrane, i.e., against a concentration gradient
  5. 3 methods of cell transports 
    what are they?
    • osmosis
  6. general transfer
    e g: filtration& simple diffusion, & Osmosis which is flow of water across a membrane living or non living are all
  7. CARRIER MEDIATED TRANSFER, uses 2 tyopes of protein carriers to transfer across cell membrane what are they ?
    • facilitated diffusion--is carrier mediated, but passive glucose which attaches itself to carriers to be transported across the PM
    • Carrier mediated Active transport---is carrier mediated to go up a gradient and needs ATP so is Active transport
    • 1)Ion Pump  eg sodium/potassium pump
    • 2)E.g.vesicular transport :Exocytosis, phagocytosis, pinocytosis)
  8. Movement of particles through a selectively permeable membrane by hydrostatic pressure
    filtration of nutrients from blood capillaries into tissue fluids
    filtration of wastes from the blood in the kidneys
    filtration (passive)
  9. Net movement of particles from area of high concentration to area of low concentration
    due to their constant, random motion Also known as movement down the concentration gradient
    simple diffusion (passive)
  10. Rate of  Diffusion
    1-Steepness of concentration gradient- ↑difference, ↑ rate

    2-Temperature-- ↑ temp., ↑ motion of particles

    3-Mass of diffusing substance--- larger molecules move slower

    4-Surface area-↑ area, ↑ rate

    5-membrane permeability -- ↑ permeability, ↑ rate
  11. Net movement of water through a selectively permeable membrane from an area of high concentration of water (lower concentration of solutes) to one of lower concentration of water
    Water can pass through plasma membrane in 2 ways:
    1.through lipid bilayer by simple diffusion
    2.through aquaporins, integral membrane proteins
  12. what are aquaporins?
    channel proteins specialized for osmosis!
Card Set
membrane transport, chapter 3
membrane transport