Cellular respiration : When a large amount of energy is released from the cell after the breaking of bonds by oxidation of complex organic molecules, it is called cellular respiration.
Function of ATP : ATP molecules absorb energy which is released in exergonic reactions. These provide energy for various endergonic reactions. Some important activities in which ATP is used are as follows:
(i) In the synthesis of carbohydrates, fats, proteins etc.
(ii) In absorption of organic and inorganic food substances.
(iii) In translocation of organic food substances.
(iv) In protoplasmic streaming.
(v) In growth.