Question

The cytochromes are found in
A) Cristae of mitochondria
(B) Lysosomes
(C) Matrix of mitochondria
(D) Outer wall of mitochondria

Answer 1

Hint: Cytochromes are the main electron carriers present in the Electron transport chain. Minerals associated with cytochrome are Fe ( iron) and Cu(copper). Cytochromes are Iron-containing molecules that are involved in electron transferring. Cytochromes were discovered by McCann and the term cytochrome was given by K.P. Kailin.

Complete answer:
The electron transport system usually takes place in the mitochondria. It occurs as the last step of aerobic respiration. The electron transport system contains a series of properly arranged 9 electron carriers that are commonly called Coenzymes, in the inner membrane of the mitochondria, including the cristae of mitochondria. Mitochondria are surrounded by two membranes outer and inner. Inner membrane forms a number of infoldings called cristae. The coenzymes are only found in the inner membrane.

Now let us match this position with the given options:-
Cristae of mitochondria :- Mitochondria are surrounded by two membranes outer and inner. Inner membrane forms a number of infoldings called cristae. This cristae contains coenzymes for electron transport chains so cytochrome occurs here. Thus this option is correct.
Lysosomes :- they are also known as suicidal bags. They are not involved in the electron transport chain so cytochromes are not present in them. Thus this option is not correct.
Matrix of mitochondria :- matrix lies inside the inner membrane of mitochondria but in matrix electron transport chains do not occur. Thus they do not have cytochromes. Thus this option is not correct.
Outer wall of mitochondria :- this membrane is generally made up of 40% lipid and 60% proteins. So electron transport chains do not occur. Thus they do not have cytochromes. Thus this option is not correct.

Our required answer is a) cristae of mitochondria.

Note: Cytochromes are mostly home containing compounds that are proteinaceous in nature. They occur in bacteria and in eukaryotes in organelle known as mitochondria. Mitochondria are the main site of aerobic respiration. They are miniature biochemical factories where foodstuff is oxidised to carbon dioxide and water.