Explanation

Carotenoids are accessory photosynthetic pigments with several roles: they give autumn leaves their yellow-orange hues, protect chlorophyll from photo-oxidation by dissipating excess light energy, and (as in lutein and zeaxanthin of the macula) play a photoprotective role in human eyes. The reaction centre of a photosystem, however, is composed of special chlorophyll-a molecules (P680/P700), not carotenoids. Carotenoids only harvest light and pass the energy onward. Hence serving as the reaction centre is not a carotenoid function.