Question

Redox reactions involving Fe2+ and Fe3+ occur during aerobic cellular respiration. Where do these reactions take place?

Answer 1

Those redox cycles occur in the electron transport chain (ETC) of aerobic respiration — specifically in the protein complexes and mobile carriers embedded in the inner mitochondrial membrane. Iron alternates between Fe2+ and Fe3+ in iron–sulfur proteins and heme-containing cytochromes (and in cytochrome c), which pass electrons along the ETC to oxygen (forming water). (In bacteria the same reactions occur in the plasma membrane.)