ELECTRON TRANSPORT SYSTEM or TERMINAL OXIDATION OF REDUCED CO-ENZYME or OXIDATIVE PHOSPHORYLATION or RESPIRATORY CHAIN

 The last step in aerobic respiration is the oxidation of reduced co-enzymes produced during glycolysis and Kreb’s cycle by molecular O2 through FAD, cyt. b, cyt. c, cyt. a and cyt.a3 (cytochrome oxidase).

Two H-atoms or electrons from the reduced coenzyme (NADH2 or NADPH2) travel through FAD and the cytochromes each with a more positive oxidation-reduction potential and ultimately combine with1/2 O2 molecule to produce one molecule of H2O. This is called Termination Oxidation.