How does ATP release energy?
Chemical properties ATP consists of adenosine – itself composed of an adenine ring and a ribose sugar – and three phosphate groups (triphosphate). The phosphoryl groups, starting with the group closest to the ribose, are referred to as the alpha (α), beta (β), and gamma (γ) phosphates. The system of ATP and water under standard conditions and concentrations is extremely rich in chemical energy; the bond between the second and third phosphate groups is loosely said to be particularly high in energy. Strictly speaking, the bond itself is not high in energy (like all chemical bonds it requires energy to break), but energy is produced when the bond is broken and water is allowed to react with the two products. Thus, energy is produced from the new bonds formed between ADP and water, and between phosphate and water. The net change in energy at Standard Temperature and Pressure of the decomposition of ATP into hydrated ADP and hydrated inorganic phosphate is -12 kcal / mole in vivo (inside o
