Reactions leading to the oxidation of reduction equivalents ([H₂]) produced by various metabolic pathways.

This oxidation corresponds to the explosive reaction of hydrogen and oxygen. A part of the energy liberated in this reaction, is conserved in the form of (ATP) and can be used for energy consuming metabolic reactions. The respiratory chain is located within the mitochondria of our cells. Because it is the main source of ATP in our body, mitochondria are called the "power stations" of cells.