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Redox enzymes in the electron transport chain have an active redox center. In th

ID: 48064 • Letter: R

Question

Redox enzymes in the electron transport chain have an active redox center. In the iron-sulfur complexes, the iron center changes oxidation states depending upon gaining or losing electrons. The image below represents the simplest of Fe-S clusters, ones found prinicipally in bacteria, with the iron atom situated within sulfur atoms. Which of the following equations correctly identifies a change in oxidation state for the iron atom.

Fe0 + 1e- --> Fe1+ Fe2+ + 1e- --> Fe3+ Fe3+ --> 1e- + Fe2+ Fe1+ + 1e- --> Fe2+ Fe3+ + 1e- --> Fe2+

Explanation / Answer

Fe3+ + 1e- --> Fe2+

Generally iron exists in two oxidation states namely, oxidised (Fe+3) and reduced (Fe+2). Loss of electrons is oxidation and gain of electrons is reduction. In the above equation, iron is acceptiong on electron pair and is become reduced.