Electron Transport System

Electron Transport System - final electron acceptor is an...

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Electron Transport System The electron transport system occurs in the cristae of the mitochondria, where a series  of cytochromes (cell pigments) and coenzymes exist. These cytochromes and  coenzymes act as carrier molecules and transfer molecules. They accept high-energy  electrons and pass the electrons to the next molecule in the system. At key proton- pumping sites, the energy of the electrons transports protons across the membrane into  the outer compartment of the mitochondrion. Each NADH molecule is highly energetic, which accounts for the transfer of six protons  into the outer compartment of the mitochondrion. Each FADH 2  molecule accounts for  the transfer of four protons. The flow of electrons is similar to that taking place in  photosynthesis. Electrons pass from NAD to FAD, to other cytochromes and  coenzymes, and eventually they lose much of their energy. In cellular respiration, the 
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Unformatted text preview: final electron acceptor is an oxygen atom. In their energy-depleted condition, the electrons unite with an oxygen atom. The electron–oxygen combination then reacts with two hydrogen ions (protons) to form a water molecule (H 2 O) The role of oxygen in cellular respiration is substantial. As a final electron receptor, it is responsible for removing electrons from the system. If oxygen were not available, electrons could not be passed among the coenzymes, the energy in electrons could not be released, the proton pump could not be established, and ATP could not be produced. In humans, breathing is the essential process that brings oxygen into the body for delivery to the cells to participate in cellular respiration....
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