Final answer:
ATP is the primary energy-supplying molecule in cells, and it is used to perform cellular work by donating its phosphate group to another molecule via phosphorylation.
Step-by-step explanation:
Adenosine triphosphate (ATP) is the primary energy-supplying molecule for living cells. It consists of a nucleotide, a five-carbon sugar, and three phosphate groups. The bonds that connect the phosphates have high-energy content. When ATP hydrolysis occurs, the energy released is used to perform cellular work by coupling the exergonic reaction of ATP hydrolysis with endergonic reactions. ATP donates its phosphate group to another molecule via phosphorylation, which allows the phosphorylated molecule to undergo its endergonic reaction.