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Unformatted text preview: What has been described above are the noncyclic energy-fixing reactions. Certain microorganisms are also known to participate in cyclic energy-fixing reactions. Excited electrons leave the chlorophyll molecules, pass through coenzymes of the electron transport system, and then follow a special pathway back to the chlorophyll molecules. Each electron powers the proton pump and encourages the transport of a proton across the membrane. This process enriches the proton gradient and eventually leads to the generation of ATP. ATP production in the energy-fixing reactions of photosynthesis occurs by the process of chemiosmosis. Essentially, it consists of a rush of proteins across a membrane (the microbial membrane, in this case) accompanied by the synthesis of ATP molecules. It has been calculated that the proton concentration on one side of the membrane is 10,000 times that on the opposite side of...
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- Fall '07