Cellular metabolism is the set of biochemical processes that take place in living organisms to sustain life. Synonyms for cellular metabolism include cellular respiration, metabolic processes, metabolic pathways, intermediary metabolism, and bioenergetics. Cellular respiration refers to the breakdown of glucose and other nutrients to release energy in the form of ATP. Metabolic processes are the chemical transformations that occur within cells to convert nutrients into usable energy and materials. Metabolic pathways are the sequences of enzyme-catalyzed reactions that convert one compound into another. Intermediary metabolism is the set of reactions that occur between the breakdown of nutrients and the synthesis of molecules needed for cellular function. Bioenergetics is the study of the transformation of energy in biological systems.