Class 4: Equilibrium Potential and Resting Membrane Potential

Question 1

Write the Nernst equation and indicate how this equation accounts for both the chemical and electrical driving forces that act on an ion.

Question 2

Define the concepts of electrochemical equilibrium and equilibrium potential. Calculate the equilibrium potential for Na+/K+/Ca2+ using the Nernst equation. What accounts for the differences between these 3 ions.

Question 3

List the conditions that must exist and which proteins must be present in order for a cell to have a negative resting membrane potential (i.e. think about ion channels, carrier proteins, etc.)

Question 4

Explain which types of channels are responsible for the resting membrane potential.

Question 5

Explain why the resting membrane potential closer to EK than to ENa. What are two reasons why changes in extracellular K+ concentration have more dramatic effects on resting membrane potential than Na+.

Question 6

Write the GHK equation and explain what the relative ion permeability represents. Explain which variables in this equation are generally quite stable and which can vary on a moment-to-moment basis in a neuron.

Question 7

Be able to determine the net direction of an ion’s movement based on its electrical and chemical gradients.