The term metabolism comprises the entire physical and chemical processes involved in the maintenance and reproduction of life in which nutrients are broken down to generate energy and to give simpler molecules (catabolism) which by themselves may be used to form more complex molecules (anabolism).
In case of heterotrophic organisms, the energy evolving from catabolic processes is made available for use by the organism.
In medicinal chemistry the term metabolism refers to the biotransformation of xenobiotics and particularly drugs. (See also Biotransformation; Xenobiotic).
