The process involving a set of chemical reactions that modifies a molecule into another to essentially maintain the living state of a cell or an organism
Metabolism pertains to all the chemical reactions involved in modifying a molecule into another. The major functions of metabolism are for storage (i.e. converting certain molecules as an energy source for various cellular processes), for transforming certain molecules as a component of biomolecules (e.g. carbohydrates, proteins, lipids, and nucleic acids), and for eliminating byproducts such as nitrogenous wastes.
Metabolism includes processes for cell growth, reproduction, response to environment, survival mechanisms, sustenance, and maintenance of cell structure and integrity. These chemical reactions utilize various enzymes. Metabolism may be categorized into two: catabolism and anabolism. Catabolism includes a series of degradative chemical reactions that break down complex molecules into smaller units, usually releasing energy in the process. Anabolism includes a sequence of chemical reactions that constructs or synthesizes molecules from smaller units, usually requiring input of energy (ATP) in the process.
A disorder or dysfunction in the metabolism is referred to as metabolic disorder.
Word origin: Greek metabolē (“change”), frommetaballein (“to change”), meta– + ballein (“to throw”)