Answer:
During the process of cellular respiration,that comprises three further processes (glycolysis, Kreb cycle and electron transport chain) the energy present in glucose molecules is transformed into ATP.
Explanation;
Cellular respiration is a process in which sugar breaks down to produce H2O and carbon di oxide, and during the same process energy in the form of ATP packets is formed that can be later on used by an organism to perform day to day activities.
Cellular respiration is the process during which energy present in the bonds of glucose are transformed into the form of ATP. ATP is the molecule that stores energy in its phosphate (PO4) bonds.
Hydrolysis of one phosphate bond of ATP releases almost 7.3 kJ of energy. Similarly, the hydrolysis of second phosphate bond of Adenosine mono phosphate releases around 3.4 to 3.6 kJ of energy. Therefore, the total amount of energy released from ATP hydrolyses is around 18 to 18.2 kJ of energy!
This energy is all that living organisms need to fulfill their cellular and physical work requirements.
Hope it help!