Lecture 3--Membrane Potentials

Question 1

T/F: The plasma membrane is electrically polarized

Answer 1

True

Question 2

The voltage difference across the cell membrane

Answer 2

Membrane Potential (Vm)

Question 3

Cells use ___ as a battery and for signaling purposed

Answer 3

membrane potential

Question 4

Membrane Potential (Vm) is proportional to:

Answer 4

separation of positive and neg ions (sep of charge across membrane)

Question 5

____ acts as a capacitor and stores charge

Answer 5

cell membrane

Question 6

Several factors influence distribution of ions across cell membrane:

Answer 6

1) active transport of the ion
2) conc gradient
3) volatge gradient
4) conductance of ion across membrane

Question 7

Conductance of the ion across the membrane is determined by:

Answer 7

1) number of channels aka permeability
2) simple diffusion

Question 8

Ion diffusio is determijed by the

Answer 8

E/C Gradient

Question 9

The concentration difference for K+ across membrane is roughly balanced by the intracellular negative charge created by ___

–efflux due to:
–influx due to:

Answer 9

impermeant anions

efflux: conc grad
influx: elect grad

Question 10

The electrical potential that counters net diffusion of K+ is ____

Answer 10

K+ equilibrium potential (Ek)

Question 11

What 2 things need to be considered when determining the effect of an ion on the membrane potential?

Answer 11

1) concentration gradient
2) permeability

(nernst eq assumes membrane is 100% perm to said ion)

Question 12

Equation including permeability of all ions contributing to membrane potential

Answer 12

Goldman Constant Field Equation