Protein molecules called cytochromes are part of the electron transport chain. they are nearly identical in every known aerobic organism. how do these molecules show the unity of life on earth?

Cytochromes:- They are iron containing hemoproteins that serve many cellular functions including energy production, steroid biosynthesis, and degradation of toxins.

Cytochromes occur in all organisms except a few obligate anaerobes. They are structurally similar among organisms. These are proteins to which one to two tetrapyrrole rings are bound. These tetrapyrroles are very similar to the chromophores of chlorophylls in plants. However, chlorophylls(in plants) contain Mg++ as the central atom in the tetrapyrrole, whereas the cytochromes(in aerobic animals) have an iron atom (Figure).

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