what functional group is commonly used in cells to transfer energy from one organic molecule to another?

The functional group commonly used in cells to transfer energy from one organic molecule to another is the phosphate group. Specifically, cells use adenosine triphosphate (ATP), which contains three phosphate groups, to transfer energy. The energy transfer occurs through the breaking and forming of high-energy phosphate bonds, often by transferring a phosphate group (phosphorylation) from ATP to another molecule, thus powering various cellular processes.