Question

Explain how nucleoside triphosphates (such as ATP) act as carriers of chemical energy.

Answer 1

In these molecules, there is a phosphoric anhydride linkage between the phosphates. Hydrolysis of this linkage (i.e., of ATP to ADP and phosphate) is a highly exergonic reaction that results in the release of a large amount of free energy. Conversely, the input of a large amount of free energy is required for the synthesis of the linkage; i.e., for the phosphorylation of ADP to form ATP. Thus,synthesis of ATP results in the storage of energy that can be released upon hydrolysis.