Elementary plant Biochemistry and Biotechnology (2+1)

Carotenoids

The accessory pigments can also serve as receptors of light energy.
 
• The carotenoids are long polyisoprenoid (tetra – terpene) molecules having conjugated double bonds. Each end of the molecule contains an unsaturated substituted cyclohexane ring. There are two types of carotenoid pigments in chloroplasts, the carotenes which are tetreterpene hydrocarbons without oxygen and the other is xanthophylls which are very similar in structure but contain oxygen atoms in their terminal rings. The most abundant carotene is β – carotene and the xanthophylls is violaxanthin. The carotenoids absorb light in the range 400-500 nm.