Physiology, Adenosine Triphosphate

In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan.


The body is a complex organism, and as such, it takes energy to maintain proper functioning. Adenosine triphosphate (ATP) is the source of energy for use and storage at the cellular level. The structure of ATP is a nucleoside triphosphate, consisting of a nitrogenous base (adenine), a ribose sugar, and three serially bonded phosphate groups. ATP is commonly referred to as the "energy currency" of the cell, as it provides readily releasable energy in the bond between the second and third phosphate groups. In addition to providing energy, the breakdown of ATP through hydrolysis serves a broad range of cell functions, including signaling and DNA/RNA synthesis. ATP synthesis utilizes energy obtained from multiple catabolic mechanisms, including cellular respiration, beta-oxidation, and ketosis.

The majority of ATP synthesis occurs in cellular respiration within the mitochondrial matrix: generating approximately thirty-two ATP molecules per molecule of glucose that is oxidized. ATP is consumed for energy in processes including ion transport, muscle contraction, nerve impulse propagation, substrate phosphorylation, and chemical synthesis. These processes, as well as others, create a high demand for ATP. As a result, cells within the human body depend upon the hydrolysis of 100 to 150 moles of ATP per day to ensure proper functioning. In the forthcoming sections, ATP will undergo further evaluation of its role as a crucial molecule in the daily functioning of the cell.

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