The chemical reactants on the left produce ATP on the right.
Step-by-step explanation:
The energy in the cell is in the form of ATP which means it is the energy currency of the cell. The hydrolysis of ATP produces ADP, phosphate group and energy. The reaction is reversible and since the produced ATP gets used up quickly the generation of ATP from ADP and phosphate is a an important reaction.
The reaction of hydrolysis is represented as
Since ATP is an energy source mere combination of ADP and phosphate group cannot produce ATP. The reaction requires input energy.