Final answer:
The removal of a phosphate group from an ATP molecule releases energy. This process of dephosphorylation occurs through hydrolysis and makes energy available for cellular activities.
Step-by-step explanation:
When a phosphate group is removed from an ATP (adenosine triphosphate) molecule, energy is released. This process is known as dephosphorylation. ATP consists of a base (adenine), a sugar (ribose), and three phosphate groups. The bonds between these phosphate groups, particularly the terminal bond, hold a high energy potential due to the repulsion of the negatively charged phosphate groups.
Energy is required to add a phosphate group to ADP (adenosine diphosphate), forming ATP, which stores energy. Conversely, when ATP is converted to ADP and a phosphate group, through a process called hydrolysis, the energy stored in the bond is released. This released energy is then available for the cell to perform work, such as muscle contraction or active transport across membranes.