The chemical process animals use to convert food into energy is called cellular respiration. During this process, cells break down glucose and other organic molecules through a series of metabolic pathways, primarily in the mitochondria. This process releases energy stored in chemical bonds, which is ultimately converted into ATP (adenosine triphosphate), the energy currency of the cell. Cellular respiration can occur aerobically, utilizing oxygen, or anaerobically, without oxygen, producing energy for cellular functions.