How does chemiosmosis produce ATP?

Chemiosmosis is a biological mechanism that is part of cellular respiration. It occurs in the inner membrane of mitochondria in eukaryotic cells. During the cellular respiration process, high energy electrons are passed through four protein complexes, which are part of the electron transport chain embedded in the inner mitochondrial layer. 

As the electrons pass through the electron transport chain, some of the protein complexes actively pump protons (H+ ions) across the membrane from the mitochondrial matrix to the intermembrane space. This creates a concentration gradient of protons, with more protons in the intermembrane space. 

ATP synthase, an enzyme complex embedded in the inner mitochondrial membrane, facilitates the movement of protons across the membrane from the side of higher concentration to the side with lower concentration. ATP synthase uses the energy generated by the flow of protons to convert ADP (adenosine diphosphate) and inorganic phosphate (Pi) to ATP.