Transport Electrophysiology

  1. Def: flux
    movement of mass substances across a membrane
  2. What substances can freely diffuse across a membrane?
    • Gases
    • Hydrophobic
    • Small polar
  3. What substances can cross a membrane via facilitated diffusion?
    A substance moving DOWN its concentration gradient
  4. Def: active transport (primary)
    • Movement of a substance against its concentration gradient.
    • Energy required in the form of ATP.
  5. Def: active transport (secondary)
    Movement of one substance against its gradient, coupled with movement of another substance down its gradient.
  6. Def: electrochemical potential
    • Symbolized by (C)
    • A difference in either electric potential or concentration of a substance across a membrane.
  7. What is flux rate dependent on?
    Determined by electrochemical potential (deltaC) and Membrane potential (P)
  8. (P) is a function of what?
    Molecular size and membrane partition coefficient, i.e., membrane solubility
  9. What is the partition coefficient (beta)?
    the ratio of the [ ] of the substance in the membrane, to [ ] in the aqueous solution in contact with the membrane.
  10. When the C(outside) = C(inside), the partition coefficient (beta) = what?
    Beta = 1
Card Set
Transport Electrophysiology