Fundamentals of Microbiology

3.1.5 Respiration

After glucose has been broken down to pyruvic acid, the pyruvic acid can be channeled into the next step of either fermentation or respiration. Respiration is defined as an ATP-generating process in which molecules are oxidized and the final electron acceptor is an inorganic molecule. An essential feature of respiration is the operation of an electron transport chain. In aerobic respiration the final electron acceptor is O₂, in anaerobic respiration the final electron acceptor is an inorganic molecule other than molecular oxygen or rarely an organic molecule.