Question

In a two-compartment model of a cell with a K+- and Na+-permeable membrane and a 10-fold excess of K+ in the inside compartment, how would the membrane potential change if all K+ ions were replaced by Na+ ions?

a. It would double.

b. It would be reduced by half.

c. It would not change.

d. It would become positive.

e. No potential would be generated.

Answer 1

In a two-compartment model of a cell with a K+- and Na+-permeable membrane and a 10-fold excess of K+ in the inside compartment, how would the membrane potential change if all K+ ions were replaced by Na+ ions?
Correct option:

• e. No potential would be generated

Explanation: In case of the described situation if there is 10 fold increase in the concentration of potassium inside the cell the resting membrane potential of the cell will be drastically lowered and the cell will not be able to trigger an action potential where the resting potential need to be on the positive side in order for triggering an action potential. Hence option e. is correct.