Define chemiosmosis.

Chemiosmosis is the movement of ions across a semipermeable membrane, down their electrochemical gradient. ATP synthase is the enzyme that makes ATP by chemiosmosis. It allows protons to pass through the membrane and uses the free energy difference to phosphorylate adenosine diphosphate (ADP), making ATP. The generation of ATP by chemiosmosis occurs in mitochondria and chloroplasts, as well as in most bacteria and archaea, an electron transport chain pumps H+ ions in the thylakoid spaces through thylakoid membranes. The energy from the electron movement through electron transport chains cross through ATP synthase which allows the proton to pass through them and use this free energy difference to photophosphorylate ADP making ATP.