Anaerobic Respiration

In the complete absence of molecular oxygen, glucose cannot be broken down completely -- instead it is only incompletely degraded, most commonly into either ethyl alcohol or lactic acid, and the process is called anaerobic respiration. It proceeds in just two steps: (1) glycolysis, the same glucose-to-pyruvate splitting used in aerobic respiration, followed by (2) fermentation, in which the pyruvic acid produced is converted into alcohol or lactic acid instead of being sent on to the mitochondria. Because the substrate is never fully oxidised, far less energy is extracted than in aerobic respiration. The full mechanism and si …