<P> ATP is stable in aqueous solutions between pH 6.8 and 7.4, but it is rapidly hydrolysed at more extreme pH's . ATP hydrolyses to ADP and phosphate . Living cells maintain the ratio of ATP to ADP at a point ten orders of magnitude from equilibrium, with ATP concentrations fivefold higher than the concentration of ADP . </P> <P> In the context of biochemical reactions, these anhydride bonds are frequently referred to as high - energy bonds . </P> <P> The hydrolysis of ATP into ADP and inorganic phosphate releases 30.5 kJ / mol of enthalpy, with a change in free energy of 3.4 kJ / mol . The energy released by cleaving either a phosphate (P) or pyrophosphate (PP) unit from ATP at standard state of 1 M are: </P> <Dl> <Dd> ATP + H O → ADP + P ΔG ° = − 30.5 kJ / mol (− 7.3 kcal / mol) </Dd> <Dd> ATP + H O → AMP + PP ΔG ° = − 45.6 kJ / mol (− 10.9 kcal / mol) </Dd> </Dl>

What is meant by tri in adenosine triphosphate