Final answer:
Chemiosmosis is the process that drives the movement of protons across the mitochondrial membrane into the intermembrane space. This movement is powered by the proton motive force (PMF) created by the electron transport chain (ETS). ATP synthase uses this proton gradient to generate ATP.
Step-by-step explanation:
The movement of protons across the mitochondrial membrane into the intermembrane space is driven by a process called chemiosmosis. During chemiosmosis, electrons move through the electron transport chain (ETS) and pump hydrogen ions (protons) across the membrane, creating an electrochemical gradient known as the proton motive force (PMF).
This proton gradient is then used by ATP synthase, a membrane-bound enzyme complex, to generate ATP from ADP and inorganic phosphate.