Noncyclic electron flow

Noncyclic electron flow - Noncyclic electron

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Noncyclic electron flow,  the predominant route, produces both ATP and NADPH. Photosystem II absorbs a photon of light. One of the electrons of P680 is excited to a  higher energy state. This electron is captured by the primary electron acceptor, leaving the reaction center  oxidized. An enzyme extracts electrons from water and supplies them to the oxidized reaction  center. This reaction splits water into two hydrogen ions and an oxygen atom that  combines with another oxygen atom to form O2. Photoexcited electrons pass along an electron transport chain before ending up at an  oxidized photosystem I reaction center. As these electrons “fall” to a lower energy level, their energy is harnessed to produce  ATP. Meanwhile, light energy has excited an electron of PS I’s P700 reaction center. The  photoexcited electron was captured by PS I’s primary electron acceptor, creating an  electron “hole” in P700. This hole is filled by an electron that reaches the bottom of the  electron transport chain from PS II. Photoexcited electrons are passed from PS I’s primary electron acceptor down a second 
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Noncyclic electron flow - Noncyclic electron

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