Passive Transport

DIFFUSION
1. small nonpolar molecules move through the hydrophobic region of the phospholipid bilayer
  1. CO2
  2. O2
  3. H20
    1. OSMOSIS
    2. Slow
    3. small amounts of H2O only
  4. glycerol
  5. ethanol
  6. N2
2. uses kinetic energy of molecules
3. only effective over very small distances
4. moves molecules to reach an equilibrium
  1. At equilibrium movement of molecules occurs but there is no net change
FACILITATED DIFFUSION
1. Requires a transmembrane protein that spans the phospholipid bilayer
  1. CHANNEL PROTEINS
    1. Aquaporins
      1. Rapid movement of H2O
    2. Ion channels
      1. charged ions
        Chlorine Cl-
        Sodium Na+
        Potassium K+
        Calcium Ca2+
        Hydrogen Ion H+
    3. forms hydrophilic pore
  2. CARRIER PROTEIN
    1. Glucose transport into the cell
      1. Uses Symport with Na+ and glucose
    2. binds to a specific molecule
    3. undergo a change in conformation
2. polar molecules
3. ions, amino acids, nucleoside, carbohydrates
does not require ATP
moves molecules along a concentration gradient from areas of high concentration to areas of low concetration

Resource summary

	Created by Julie Thompson about 8 years ago