Light is an essential abiotic physical factor that directly and indirectly affects organisms and the surroundings they live in. Some organisms like photoautotrophs are dependent on light to derive their energy through photosynthesis and synthesize food. Thylakoid membranes have photosystems with pigments that are capable of extracting energy from photons and absorbing it.
The absorbed energy or photon is passed from pigments in the antenna complex to the reaction center that has the main pigment chlorophyll a. Here in the reaction center, it sets a redox chain concerned with electron transport. A primary acceptor accepts an electron from chlorophyll a and passes into ETC.
The flow of electrons in the Electron Transport Chain helps in the generation of energy through the generation of a proton gradient according to Chemiosmotic theory. These reactions occur in the Photosystem II reaction center. In photosystem I, there is a cyclic flow of electrons due to which no NADPH is formed.
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