Which statement about the Na+/K+-ATPase pump is accurate?

• A. It uses energy to pump ions against their gradients, helping maintain resting potential.
• B. It directly generates action potentials.
• C. It transports neurotransmitters across the synaptic cleft.
• D. It forms part of the myelin sheath.

Answer: (A)

The key idea is that the Na+/K+-ATPase uses energy to move ions against their gradients, which keeps the ion distributions inside and outside the neuron stable and establishes the resting membrane potential. It moves three Na+ ions out of the cell for every two K+ ions it brings in, using ATP in the process. This continual pumping maintains the steep Na+ outside/ K+ inside gradient that underpins excitability, and it helps reset and sustain the resting potential after neural activity. It does not directly generate action potentials—that role belongs to voltage-gated channels that rapidly change membrane permeability to Na+ and K+. It also does not transport neurotransmitters across the synaptic cleft or form part of the myelin sheath.