What is function of carotene in photosynthesis?
Carotene is closely allied to chlorophyll in plants and organisms that undergo photosynthesis. It serves two roles. First it absorbs some of the sunlight that is missed by the chlorophyll molecules. Secondly, because of its high number of reactive double bonds, it makes a good ‘sponge’ to react with, and therefore ‘mop up’, energetic oxygen molecules that might otherwise oxidise and degrade more important parts of the plant structure. In a typical leaf, there is a ratio of chlorophyll to carotenoid of about 1:3, and the darker the leaf the more carotenoids it contains. Normally, however, the green colour of chlorophyll is so intense it masks the more subtle oranges and reds of the carotenoids. In Autumn however, when the chlorophyll decays, the green fades and leaves turn red and yellow.
