carotenoid

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carotenoid A generic term for water-insoluble, polyisoprenoid pigments, which often function as accessory photosynthetic pigments in higher plants and photosynthetic bacteria, with absorption peaks between 450 and 480 nm. The group includes the carotenes, which are orange, and xanthophylls, which are yellow. During the senescence of leaves, chlorophyll breaks down faster than carotenoids and carotenoid colours are revealed. In the vertebrate liver, carotene is changed into (i.e. is a precursor of) vitamin A.

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