destructive metabolism; the breaking down in living organisms of more complex substances into simpler ones, with the release of energy (opposed to anabolism).
1876, katabolism, "destructive metabolism," from Greek katabole "a throwing down" (also "a foundation"), from kataballein "to throw down," from kata- "down" (see cata-) + ballein "to throw" (see ballistics). Barnhart says probably formed in English on the model of metabolism. Spelling Latinized from 1889.
The phase of metabolism in which energy, in the form of ATP, is produced by the breakdown of complex molecules, such as starches, proteins and fats, into simpler ones. Compare anabolism.
Biochemical reactions that break down molecules in metabolism. Molecules may be broken down to gain their energy or to prepare them for disposal from the body. (Compareanabolism.)
