Lecture 5 things to work on

Question 1

What is the equation for the electrochemical gradient?

Answer 1

Δμ = RTLn{[C]2/[C]1} + zF(φ2-φ1)

Question 2

What are two other names for resting membrane potential?

Answer 2

cell membrane potential

membrane potenial

Question 3

Cells can be __________ or ___________

Give an example of each

Answer 3

static (epithelial cell) or dynamic (muscle cell)

Question 4

When are diffusion potentials created?

Answer 4

When you have:

• a concentration gradient
• a selective barrier

Question 5

What is equal at equilibrium? But they are ______. Therefore the _________ potential is _______ and there is no net movement of ________

Answer 5

The chemical potential and the electrical potential, but they are opposite (in direction)
Therefore the equilibrium potential is zero and there is no net movement of ions

Question 6

What is the equation for the equilibrium potential?

Answer 6

Δμ = RTLn{[C]2/[C]1} + zF(φ2-φ1) = 0

Question 7

What is the equation that calculates the value of a diffusion potential? What does this mean?

Answer 7

This is the Nernst potential:

Ex = (RT/zF) Ln {[X]o/[X]I}

ie. if diffusion can occur freely what will the membrane potential be when the electrical and chemical gradients are equal and opposite