Which electrogenic pump primarily operates using H+ ions?

The proton pump operates primarily using H+ ions, making it the correct answer. This pump is crucial in various processes within the cell, including maintaining the electrochemical gradient across membranes.

Proton pumps actively transport hydrogen ions (H+) out of the cell, which generates a positive charge outside relative to the inside of the cell, thereby creating an electrochemical gradient. This gradient is vital for processes such as ATP synthesis in mitochondria during cellular respiration and in chloroplasts during photosynthesis.

In contrast, the sodium-potassium pump primarily involves the exchange of sodium (Na+) and potassium (K+) ions, while the calcium pump focuses on moving calcium ions (Ca2+) across membranes. The chloride pump is specific for chloride ions (Cl-). None of these pumps primarily utilize H+ ions for their main function, making the proton pump distinctly the electrogenic pump that primarily operates with hydrogen ions.