The biochemical process used by organisms to convert food into energy is called cellular respiration. This process involves breaking down glucose and other organic molecules in the presence of oxygen to produce adenosine triphosphate (ATP), the primary energy currency of the cell. Cellular respiration primarily occurs in the mitochondria of eukaryotic cells and includes several stages, such as glycolysis, the citric acid cycle, and the electron transport chain. This process is essential for powering cellular activities and maintaining life.