The respiratory chain enzymes, embedded in the mitochondrial inner membrane (MIM), couple the transport of electrons through the electron transport chain complexes (CI-CIV) to ATP production by CV. Protons extruded into the intermembrane space (IMS) by CI, CIII and CIV create an electrochemical gradient that is utilized by CV, capturing this energy by phosphorylation of ADP while translocating protons back to the mitochondrial matrix.
Other abbreviations: CoQ (coenzyme Q10, ubiquinone), cytC (cytochrome C).