Final answer:
ATP synthase utilizes the potential energy of the proton gradient to convert ADP and P into ATP.
Step-by-step explanation:
The potential energy of the proton gradient is used by ATP synthase to convert ADP and P into ATP. The movement of protons (H+) down the electron transport chain creates an electrochemical gradient, consisting of both a difference in proton concentration and a difference in electric potential. ATP synthase harnesses this proton-motive force to synthesize ATP. As protons flow through ATP synthase, the enzyme catalyzes the phosphorylation of ADP, combining it with a phosphate group (P), resulting in the formation of ATP.