Metabolism is the set of life-sustaining chemical
transformations within the cells of living organisms. These enzyme-catalyzed
reactions allow organisms to grow and reproduce, maintain their structures, and
respond to their environments. Metabolism can also refer to all chemical
reactions that occur in living organisms, including digestion and the transport
of substances into and between different cells, in which case the set of
reactions within the cells is called intermediary metabolism or intermediate
metabolism.
