Adenosine Triphosphate (ATP) Metabolism is the process by which energy stored in the form of ATP is used to fuel metabolic processes in living organisms. ATP is produced in the mitochondria of cells through the process of cellular respiration, which involves the breakdown of glucose to produce energy-rich molecules. This energy is then released when ATP is broken down into adenosine diphosphate (ADP) and inorganic phosphate (Pi). This released energy is used to power a variety of cellular processes, including muscle contraction, active transport, and protein synthesis.