Question

Cytochrome is a

• A. Mg pyrole ring
• B. Fe porphyrin ring
• C. Nucleotide
• D. Alloy of nichrome

Answer 1

Answer: (B)

Cytochromes are iron-containing heme prosthetic groups. They are most important electron carries of the respiratory chain, which are related with each other by the presence of a bound heme group whose iron atom changes from ferric $(F{e}^{+3})$ state to ferrous $(F{e}^{+2})$ state when it accepts an electron. The heme group of cytochromes consists of a porphyrin ring holding an iron atom its four nitrogens.