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A photosynthetic pigment (accessory pigment; chloroplast pigment; antenna pigment) is a pigment that is present in chloroplasts or photosynthetic bacteria and captures the light energy necessary for photosynthesis. List of photosynthetic pigments (in order of increasing polarity): Carotene: an orange pigment; Xanthophyll: a yellow pigment
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 ...
Photosynthesis is a process where light is absorbed or harvested by pigment protein complexes which are able to turn sunlight into energy. [3] Absorption of a photon by a molecule takes place when pigment protein complexes harvest sunlight leading to electronic excitation delivered to the reaction centre where the process of charge separation can take place.
P680 + is the strongest biological oxidizing agent known, with an estimated redox potential of ~1.3 V. [3] This makes it possible to oxidize water during oxygenic photosynthesis. P680 + recovers its lost electron by oxidizing water via the oxygen-evolving complex , which regenerates P680.
This process of reducing quinone is comparable to that which takes place in the bacterial reaction center. Photosystem II obtains electrons by oxidizing water in a process called photolysis. Molecular oxygen is a byproduct of this process, and it is this reaction that supplies the atmosphere with oxygen.
Location of the psa genes in the chloroplast genome of Arabidopsis thaliana.The 21 protein-coding genes involved in photosynthesis are displayed as green boxes. Photosystem I (PSI, or plastocyanin–ferredoxin oxidoreductase) is one of two photosystems in the photosynthetic light reactions of algae, plants, and cyanobacteria.
Oxygenic photosynthesis can be performed by plants and cyanobacteria; cyanobacteria are believed to be the progenitors of the photosystem-containing chloroplasts of eukaryotes. Photosynthetic bacteria that cannot produce oxygen have only one photosystem, which is similar to either PSI or PSII .
These pigments enter a high-energy state upon absorbing a photon which they can release in the form of chemical energy. This can occur via light-driven pumping of ions across a biological membrane (e.g. in the case of the proton pump bacteriorhodopsin ) or via excitation and transfer of electrons released by photolysis (e.g. in the photosystems ...