Hydrogen ions, or protons, will diffuse from an area of high proton concentration to an area of lower proton concentration, and an electrochemical concentration gradient of protons across a membrane can be harnessed to make ATP. ... ATP synthase is the enzyme that makes ATP by chemiosmosis.

Where do protons diffuse in chemiosmosis?

Chemiosmosis involves the pumping of protons through special channels in the membranes of mitochondria from the inner to the outer compartment. The pumping establishes a proton (H⁺) gradient. After the gradient is established, protons diffuse down the gradient through a transport protein called ATP synthase.

What happens during chemiosmosis?

During chemiosmosis, the free energy from the series of reactions that make up the electron transport chain is used to pump hydrogen ions across the membrane, establishing an electrochemical gradient. ... The production of ATP using the process of chemiosmosis in mitochondria is called oxidative phosphorylation.