The equilibrium potential for potassium ion occurs at approximately
A)-90 mV.
B)-70 mV.
C)+66 mV.
D)0 mV.
E)+30 mV.

Question

Quizplus · Accepted Answer

The equilibrium potential for potassium ion is approximately -90 mV. This is due to the fact that potassium ions have a higher concentration within the cell compared to outside, which causes a buildup of positive charge inside the cell. The negative membrane potential then attracts enough potassium ions outwards that there is no further build-up of charge. At this point, the potential difference across the membrane is at equilibrium and is approximately -90 mV, which is the resting membrane potential of most cells.

The Equilibrium Potential for Potassium Ion Occurs at Approximately