Question

multiple choice question
which of the following is true of depolarization?
o the na+-k+ pumps increase the ejection of na+
o excitation causes the resting voltage to become more negative
o excitation causes the resting voltage to become less negative

Explanation:

Depolarization occurs when a stimulus causes the membrane potential (resting voltage) to become less negative. The Na⁺ - K⁺ pumps are mainly involved in maintaining the resting membrane potential by ejecting Na⁺ and taking in K⁺, but their activity is not directly the cause of depolarization. When a cell is excited (e.g., in a neuron), voltage - gated Na⁺ channels open, Na⁺ flows into the cell (down its concentration gradient), and the membrane potential (which is negative at rest) becomes less negative (depolarizes). If the excitation caused the resting voltage to become more negative, that would be hyperpolarization.

Answer:

excitation causes the resting voltage to become less negative