ATP unstable molecules are the main source of energy for cells. ATP molecules are produced by the energy generated by catabolic reactions, and ATP energy is used in anabolic reactions.
ATP is produced as a result of oxidation reactions of carrier compounds, that are generated by catabolism of larger molecules. The carbohydrate glucose is catabolized to produce ATP in two ways: cellular respiration; fermentation.
Cellular respiration represents the most satisfactory way to generate ATP, since 1 glucose produces 36 ATP molecules. ATP is generated by oxidative phosphorylation, a series of redox reactions that involve the presence of oxygen.
The chemical reaction that transforms 1 glucose into 36 ATP molecules, in presence of oxygen, is described below:
`6O_2 + C_6H_12O_6-gt 6H_2O + 6CO_2`