Organisms need to obtain energy through cellular respiration in order to fuel their metabolisms, maintain homeostasis, and carry out essential functions such as growth, reproduction, and repair. Cellular respiration is the process by which cells break down glucose and other organic molecules to produce ATP, the molecule used by cells as a source of energy. Without a constant supply of ATP, cells would not be able to carry out their various functions and the organism as a whole would not be able to survive.
