Class 3: Cellular Neurophysiology (Transporters and Ion Channels)

Question 1

Describe the chemical characteristics and functions of the following components of the plasma membrane: lipid bilayer, proteins (channels, carriers), receptors, enzymes, and linkers.

Question 2

Explain the concept of selective permeability of the plasma membrane, and describe the chemical characteristics of molecules that are most likely to diffuse across the lipid bilayer.

Question 3

List the intracellular and extracellular concentrations of the following ions: K+, Na+, Cl-, Ca2+, and anions (A-). Draw a diagram of a cell showing these concentration gradients.

Question 4

Define a chemical gradient, electrical gradient, and an electrochemical gradient across the plasma membrane of a typical cell.

Question 5

Compare and contrast simple diffusion of a nonpolar, uncharged molecule across the plasma membrane vs. movement of an ion through an ion channel (facilitated diffusion).

Question 6

Explain the mechanism by which molecules can move across the plasma membrane: simple diffusion, facilitated diffusion, primary active transport, and secondary transport.

Consider (a) whether the molecule is moving against or along its gradient and (b) whether an external energy input is required.

Question 7

Explain the mechanism by which the sodium/potassium ATPase (PMPKIN) maintains the concentration gradients of K+ and Na+.