carotenoid ca·rot·e·noid (kə-rŏt'n-oid')
Any of a class of yellow to red pigments, including the carotenes and the xanthophylls. adj.
Of, relating to, or characterizing such a pigment.
|carotenoid (kə-rŏt'n-oid') Pronunciation Key
Any of a class of yellow to red pigments found especially in plants, algae, and photosynthetic bacteria. Carotenoids generally consist of conjoined units of the hydrocarbon isoprene, with alternating single and double bonds. The carotenoids absorb light energy of certain frequencies and transfer it to chlorophyll for use in photosynthesis. They also act as antioxidants for chlorophyll, protecting it from damage by oxidation in the presence of sunlight. Carotenoids are nutritionally important for many animals, giving flamingoes their color, for example, and also have antioxidant properties. There are many types of carotenoids, including carotenes and xanthophylls. See more at photosynthesis.
any of a group of nonnitrogenous yellow, orange, or red pigments (biochromes) that are almost universally distributed in living things. There are two major types: the hydrocarbon class, or carotenes, and the oxygenated (alcoholic) class, or xanthophylls. Synthesized by bacteria, fungi, lower algae, and green plants, carotenoids are most conspicuous in the petals, pollen, and fruit (e.g., carrots, sweet potatoes, tomatoes, and citrus fruits) of the flowering plants. They can also be seen in the autumn foliage of deciduous trees and shrubs. In the leaves of green plants, carotenoids serve as accessory pigments in photosynthesis, trapping solar energy and passing it to chlorophyll, the primary photosynthetic pigment. All animals and protozoans also contain carotenoids, which they obtain by ingestion. Vitamin A, for example, is one of the substances that animals obtain from the ingestion of carotene. Carotenoids also play a major role in the biological coloration of animals
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