Adenosine triphosphate (ATP) is a nucleoside triphosphate that serves as the principal energy currency of biological systems. It stores and transfers chemical energy through the hydrolysis of its terminal phosphate bonds, an exergonic reaction that releases the energy required to power nearly all cellular activities. The energy released is utilized for essential processes such as muscle contraction, active transport of ions across cell membranes, and the synthesis of complex macromolecules. Its central role in energy transfer makes it foundational to metabolism, allowing organisms to convert chemical potential energy from foodstuffs into usable molecular work.