Anaerobic cellular respiration

Cellular respiration is an energy-producing process that uses glucose to produce adenosine triphosphate or ATP, an organic compound the body can use for energy.

Anaerobic cellular respiration occurs when there is insufficient oxygen available for aerobic respiration. It provides a backup mechanism to generate ATP, the cell's energy currency.

Anaerobic respiration takes place after glycolysis. Unlike aerobic respiration, which involves the Krebs cycle and oxidative phosphorylation, anaerobic respiration proceeds through different pathways. While the exact process differs among species, in mammals, it is called lactic acid fermentation. Lactic acid fermentation does not need oxygen to proceed, although it can occur in its presence. During lactic acid fermentation, pyruvate is converted into lactic acid, and the NADH produced during glycolysis is recycled. The net release of energy comes from glycolysis in the form of 2 ATP molecules.

Diagram of the steps in anaerobic cellular respiration. First, glucose undergoes glycolysis to produce 2 molecules of pyruvate. During this step, 2 NAD is reduced to 2 NADH, and a total of 2 ATP are produced. The 2 pyruvates then go through lactic acid fermentation, which produces 2 lactic acid molecules. During this process, 2 NADH are oxidized to 2 NA Dplus.

Overview of anaerobic cellular respiration in mammals.