Ionic Potentials across Cell Membranes Conceptual Question In its resting state, the membrane surrounding a neuron is permeable to potassium ions but only slightly permeable to sodium ions. Thus, positive K ions can flow through the membrane in an attempt to equalize K concentration, but Na ions cannot as quickly. This leads to an excess of Na ions outside of the cell. If the space outside the cell is defined as zero electric potential, then the electric potential of the interior of the cell is negative. This resting potential is typically about -80 mV.
During repolarization, what is the work done (by the electric field) on the first few K⁺ ions that exit the cell?
a) -40 mV
b) +40 mV
c) -80 mV
d) +80 mV
e) -120 mV
f) +120 mV
g) 0 mV
