Final answer:
The ATPase enzyme hydrolyzes ATP into ADP and inorganic phosphate, releasing energy that powers cellular processes such as the sodium-potassium pump's active transport of ions.
Step-by-step explanation:
ATPase Enzyme Function
The ATPase enzyme functions by hydrolyzing ATP into ADP and inorganic phosphate (Pi). During this process, the enzyme catalyzes the breakdown of ATP, which releases free energy that is then used to power various cellular processes, such as active transport. In the example of the sodium-potassium pump (Na+/K+ pump), ATP hydrolysis is coupled with the transport of Na+ and K+ ions across the cell membrane, a process fundamental to maintaining cellular homeostasis. Each cycle of the Na+/K+ pump results in three Na+ ions being expelled from the cell and two K+ ions being imported into the cell. This vital function is powered by the phosphorylation of the pump, which is driven by the energy released from the hydrolysis of ATP. Therefore, the correct answer to the student's question is D. the ATPase enzyme hydrolyzes ATP into ADP and Pi.