Light-harvesting complexes of green plants light energy in the photosystem. Light-harvesting complexes of green plants The light-harvesting complex (or antenna complex) is an array of protein and chlorophyll molecules embedded in the thylakoid membrane of plants, which transfer light energy to one chlorophyll "a" molecule at the reaction center of a photosystem. The antenna pigments are predominantly chlorophyll "b", xanthophylls, and carotenes. Chlorophyll "a" is known as the core pigment. Their absorption spectra are non-overlapping and broaden the range of light that can be absorbed in photosynthesis. The carotenoids have another role as an antioxidant to prevent photo-oxidative damage of chlorophyll molecules. Each antenna complex
Photosynthetic reaction centre Photosynthetic reaction centre A photosynthetic reaction center is a complex of several proteins, pigments and other co-factors that together execute the primary energy conversion reactions of photosynthesis. Molecular excitations, either originating directly from sunlight or transferred as excitation energy via light-harvesting antenna systems, give rise to electron transfer reactions along the path of a series of protein-bound co-factors. These co-factors are light-absorbing molecules (also named chromophores or pigments) such as chlorophyll and phaeophytin, as well as quinones. The energy of the photon is used to excite an electron of a pigment. The free energy created is then used to reduce