The process that couples or links the electron transport chain to ATP synthesis.
Chemiosmosis is described as one of the mechanisms by which ATP is produced. As the electrons pass through the electron transport chain, energy is released, which is used to establish a proton gradient across a selectively-permeable membrane. The proton gradient drives the protons (hydrogen ions) to move down the gradient, releasing the energy that is in turn captured in the terminal phosphate bonds of ATP.
See also: chemiosmosis, chemiosmotic theory