Final answer:
The Na+/K+ pump is an electrogenic pump and an example of primary active transport that uses ATP to move Na+ and K+ ions against their concentration gradients.
Step-by-step explanation:
The correct answer to the student's question is B. The Na+/K+ pump is an electrogenic pump. This means it contributes to the charge difference across the cell membrane because it moves three Na+ ions out of the cell and two K+ ions into the cell, creating an electrochemical gradient. The Na+/K+ pump is an example of primary active transport as it directly uses ATP for energy to move these ions against their concentration gradients, contrast to secondary active transport, which indirectly depends on the electrochemical gradients created by primary active transport.
Although the Na+/K+ pump helps to maintain the concentration of ions on either side of the membrane, it does not establish equilibrium concentrations of sodium and potassium ions; instead, it maintains disequilibrium which is essential for various cellular functions. This disequilibrium is crucial for processes such as nerve impulse transmission and muscle contraction. It's worth noting that secondary active transport, such as the Na+/glucose symporter, can use the high concentration of sodium ions outside of the cell, maintained by the Na+/K+ pump, to move substances like glucose into the cell against their concentration gradient. However, it's important to clarify that the Na+/K+ pump itself is not a form of secondary active transport; rather, it facilitates it by creating the necessary ion gradients.