What is the primary energy currency of cells?

Adenosine triphosphate (ATP) is known as the primary energy currency of cells because it plays a critical role in storing and providing energy for various biochemical processes. ATP consists of three phosphate groups, and the energy stored in the high-energy bonds between these phosphates is released when ATP is hydrolyzed to adenosine diphosphate (ADP) and inorganic phosphate. This energy release fuels essential cellular activities such as muscle contraction, nerve impulse propagation, and biosynthesis of macromolecules.

While other compounds like NADPH, glucose, and cyclic AMP are important in metabolic processes, they serve different roles. NADPH is mainly involved in anabolic reactions and reducing power in the biosynthesis of molecules. Glucose is a primary energy source and a substrate that cells can metabolize to produce ATP, but it is not the direct energy currency itself. Cyclic AMP functions primarily as a signaling molecule within cells, influencing various metabolic pathways rather than acting as a direct energy source. Thus, ATP's unique structure and function firmly establish it as the primary energy currency in cellular metabolism.