Student Projects/Non cyclic photosphorylation

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The LHC of PS-2 absorb short red wavelength of less than 680 nm and transfer the energy to the reaction center by inductive resonance. P680 becomes exited to P680* and release energy rich electron and get oxidized to P 680+. this electron is accepted by colourless pheophytin. then the electron is transported to quinone and then to plastoquinone . Plastouinone receives two electrons from quinone and also picks up to two protons (one electron - 2 proton) from stroma and get reduced to plastoquinol . This gets oxidized by transferring its electron to cytochrome complex (cyt b6 and cyt f) and proton into the lumen of thylakoid membrane. from the cytochrome electron are transferred to plastocyanin (blue coloured copper containing protein) and become reduced . now plastocycnin transfer its electron to oxidized P700+ of ps1 and bring into the normal state. The electron deficient (or) oxidized P 680+ of PS 2 receives electron from Mn+ protein complex (OEC oxygen evolving complex having 4 Mn++ and small complex protein) and comes to normal stste. The oxidized Mn+ protein complex strongly attracts electron from water.As a result water loses electron and oxidized.

NOTE:- There is no continous movement of electrons through the photosystem 1 and photosystem 2 that electron move in zig zag manner. the process can be inhibited by weedicide DCMV (dichloro phenyl dimethly urea)