Resting Membrane Potential

Question 1

Resting membrane potential

Answer 1

-65mV - inside cell, + outside

Question 2

Electrochemical gradients

Answer 2

1. diffusional forces (chemical gradients)
   * ex. high concentration → low
2. electrical forces (electrical gradients)
   * like ions repel, oppositely charged attract

Ex. K+ wants to go outside due to chemical gradient, and inside due to electrical gradient

• High [K+] inside, - charge inside

Question 3

E_ion

Answer 3

(61.54mV/z) log ([ion]_o/[ion]_i)

Question 4

Driving Force

Answer 4

DF_ion = V_m - E_ion

Difference between where the membrane potential is, and where the ion wants the membrane potential to be

• DF → wants to make cell more + (positive ions move in, negative ions move out)

+ DF → wants to make cell more - (positive ions move out, negative ions move in)

Question 5

Na+/K+ pump

Answer 5

3 Na+ out

2 K+ in

sets up concentration gradient

Question 6

Leak channels

Answer 6

mostly permeable to K+

sets up membrane potential

Question 7

Goldman’s Eqn

Answer 7

helps determine membrane potential based on concentration gradients & relative membrane permeability to both ions