- a cycle of enzyme-catalyzed reactions in living cells that is the final series of reactions of aerobic metabolism of carbohydrates, proteins, and fatty acids, and by which carbon dioxide is produced, oxygen is reduced, and ATP is formed.
- a stage of tissue respiration: a series of biochemical reactions occurring in mitochondria in the presence of oxygen by which acetate, derived from the breakdown of foodstuffs, is converted to carbon dioxide and water, with the release of energy