Electrochemical Gradients

Question 1

Axon testing membrane potential

Answer 1

-70 mV

Question 2

Equilibrium potential

Answer 2

Voltage that occurs when the concentration and electrical gradients are in dynamic equilibrium. I.e. the flux due to the chemical gradient is equal and opposite to the flux due to the electrical gradient

Question 3

Nernst equation

Answer 3

Ek=(58/z)*log([ion]out/[ion]in)
Where Ek is eqm potential
And z is the charge is the ion
This is only valid at 20 degrees

Question 4

Goldman-Hodgkin-Katz equation

Answer 4

ENa,K=58log(Pk[K+]out+PNa[Na+]out/. Pk[K+]in+PNa[Na+]in)

Where Pk is permeability to potassium

Question 5

What is the role of the 3-Na-2-K atpase pump

Answer 5

It maintains the concentration gradient in the long term

Question 6

Secondary active transport

Answer 6

ATP used to pump an ion, in animals Na+, in plants H+, out of the cell, then as it diffuses down its conc gradient into the cell, use the energy released to pump other molecules against their conc gradient

Question 7

Chemiosmotic theory

Answer 7

An electrochemical proton gradient, the proton motive force, drives ATP synthesis in mitochondria, chloroplasts and bacteria

Question 8

E(Na)

Answer 8

+60 mV

Question 9

E(K)

Answer 9

-90 mV