How does the sodium-potassium pump make the interior of the cell negatively charged?
by expelling anions
by pulling in anions
by expelling more cations than are taken in
by taking in and expelling an equal number of cations

Option (3).

Explanation:

Cell membrane potential or transmembrane potential may be defined as the difference in the electric potential of the interior and exterior environment of the cell. The resting membrane potential of the neuronal cell is -70mV.

Generally, two potassium moves inside the cell and three sodium moves out of the cell by the help of sodium potassium pump. Hence, the interior of the cell become negative by expelling more cations than taken inside the cell.

Thus, the correct answer is option (3).

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