How does the electron transport system work?

Electrons are passed on from one member of the transport chain to another via a sequence of oxidation-reduction (redox) reactions. Some energy is released during each transmission. The released energy is captured as a proton gradient, which supplies the energy required for ATP synthases, which are also found in the mitochondrial membrane, to catalyze the synthesis of ATP from ADP (adenosine diphosphate) and phosphate.