The main energy currency of cells is adenosine triphosphate (ATP). ATP plays a crucial role in cellular metabolism, providing the energy required for various biological processes, such as muscle contraction, nerve impulse propagation, and biosynthesis of macromolecules. Cells generate ATP through processes like cellular respiration and photosynthesis. The structure of ATP consists of three phosphate groups, and when one of these phosphate bonds is hydrolyzed, energy is released for cellular work. Understanding ATP's function is fundamental in biochemistry and physiology, highlighting its importance in sustaining life.