How breakdown of water molecule occur in cyanobacteria in absence of psii?
Answers
Cyanobacteria photosystem II, Dimer, PDB 2AXT
Photosystem II (or water-plastoquinone oxidoreductase) is the first protein complex in the light-dependent reactions of oxygenic photosynthesis. It is located in the thylakoid membrane of plants, algae, and cyanobacteria. Within the photosystem, enzymes capture photons of light to energize electrons that are then transferred through a variety of coenzymes and cofactors to reduce plastoquinone to plastoquinol. The energized electrons are replaced by oxidizing water to form hydrogen ions and molecular oxygen.
By replenishing lost electrons with electrons from the splitting of water, photosystem II provides the electrons for all of photosynthesis to occur. The hydrogen ions (protons) generated by the oxidation of water help to create a proton gradient that is used by ATP synthase to generate ATP. The energized electrons transferred to plastoquinone are ultimately used to reduce NADP+
to NADPH or are used in Non cyclic photophosphorylation.
Cyanobacteria are autotrophic microbes found in aquatic and Terrestrial environment .Most of these fix atmospheric nitrogen .
example :- nostoc ,oscillatoria and anaebena.
In paddy fields cyanobacteria serve as an important biofertilizer as they enrich the nitrogen content in the soil. They also add organic matter to the soil. Thus increasing the fertility .
Thus the application of cyanobacteria helps in improving agricultural output .