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In such cases, the electron transfer is termed intermolecular electron transfer. A famous example of an inner sphere ET process that proceeds via a transitory bridged intermediate is the reduction of [CoCl(NH 3) 5] 2+ by [Cr(H 2 O) 6] 2+. [5] [6] In this case, the chloride ligand is the bridging ligand that covalently connects the redox ...
In outer sphere redox reactions no bonds are formed or broken; only an electron transfer (ET) takes place. A quite simple example is the Fe 2+ /Fe 3+ redox reaction, the self exchange reaction which is known to be always occurring in an aqueous solution containing the aquo complexes [Fe(H 2 O) 6] 2+ and [Fe(H 2 O)6] 3+.
Ferredoxins (from Latin ferrum: iron + redox, often abbreviated "fd") are iron–sulfur proteins that mediate electron transfer in a range of metabolic reactions. The term "ferredoxin" was coined by D.C. Wharton of the DuPont Co. and applied to the "iron protein" first purified in 1962 by Mortenson, Valentine, and Carnahan from the anaerobic bacterium Clostridium pasteurianum.
Outer sphere electron transfer can occur between chemical species that are identical except for their oxidation state. [4] This process is termed self-exchange. An example is the degenerate reaction between the tetrahedral ions permanganate and manganate:
An electron transport chain (ETC [1]) is a series of protein complexes and other molecules which transfer electrons from electron donors to electron acceptors via redox reactions (both reduction and oxidation occurring simultaneously) and couples this electron transfer with the transfer of protons (H + ions) across a membrane.
The difference between Photosystem II and the bacterial reaction center is the source of the electron that neutralizes the pair of chlorophyll a molecules. In the bacterial reaction center, the electron is obtained from a reduced compound haem group in a cytochrome subunit or from a water-soluble cytochrome-c protein.
For example, an enzyme that catalyzed this reaction would be an oxidoreductase: A – + B → A + B – In this example, A is the reductant (electron donor) and B is the oxidant (electron acceptor). In biochemical reactions, the redox reactions are sometimes more difficult to see, such as this reaction from glycolysis:
The term "Reverse electron transfer" is used in regard to the reversibility of the reaction performed by complex I of the mitochondrial or bacterial respiratory chain. Complex I is responsible for the oxidation of NADH generated in catabolism when in the forward reaction electrons from the nucleotide (NADH) are transferred to membrane ...