carotene(redirected from Alpha-ring)
Also found in: Dictionary, Thesaurus, Medical.
carotene(kâr`ətēn'), long-chained, unsaturated hydrocarbon found as a pigment in many higher plants, particularly carrots, sweet potatoes, and leafy vegetables. Carotene is thought to assist in trapping light energy for photosynthesisphotosynthesis
, process in which green plants, algae, and cyanobacteria utilize the energy of sunlight to manufacture carbohydrates from carbon dioxide and water in the presence of chlorophyll. Some of the plants that lack chlorophyll, e.g.
..... Click the link for more information. or to aid in chemical reduction. It is important in animal biology as the main dietary source of vitamin A (see vitaminvitamin,
group of organic substances that are required in the diet of humans and animals for normal growth, maintenance of life, and normal reproduction. Vitamins act as catalysts; very often either the vitamins themselves are coenzymes, or they form integral parts of coenzymes.
..... Click the link for more information. ), which is produced by splitting one molecule of carotene into two molecules of vitamin A. Carotene that is thus converted is called provitamin A. This reaction occurs in either the liver or intestinal wall. The absorption of dietary carotene is dependent on the action of bile. Its absorption is less efficient than that of vitamin A. High intake of dietary carotene is being studied for its disease prevention potential. Carotenes are the simplest of a group of natural pigments called carotenoids, of which there are more than 600.
The Columbia Electronic Encyclopedia™ Copyright © 2013, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/
C40H56 Any of several red, crystalline, carotenoid hydrocarbon pigments occurring widely in nature, convertible in the animal body to vitamin A, and characterized by preferential solubility in petroleum ether. Also known as carotin.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
any of four orange-red isomers of an unsaturated hydrocarbon present in many plants (β-carotene is the orange pigment of carrots) and converted to vitamin A in the liver. Formula: C40H56
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005