Question

In Mitochondria, enzyme cytochrome oxidase is present in
A. Outer membrane
B. Peri mitochondrial space
C. inner membrane
D. Matrix

Answer 1

Hint: cytochrome oxidase is present in either bacteria or eukaryotic organelles like mitochondria. So in case of mitochondria cytochrome is present in the cristae of the inner membrane. We have to think about this inner membrane.

Complete answer:
Mitochondria unless specifically stained are not easily visible under the microscope. Mitochondria are stained by Janus green B. DNA is covered by a double unit membrane. The outer membrane is smooth and inner one folds into several folds called cristae. The inner membrane has fewer phospholipids (Phosphatidylcholine) and cholesterol as compared to the outer membrane. The phospholipid in the inner membrane is mainly phosphatidylglycerol and the Inner membrane has more proteinaceous substance.
The outer membrane and the inner membrane of mitochondria is dividing its lumen distinctly into two aqueous compartments, i.e. the outer and the inner compartment. The inner compartment filled with a dense or hygroscopic homogeneous substance is called a matrix. In the organelle, the outer membrane has continuously limited boundaries. The two membranes have their specific enzymes associated with the mitochondrial function also help in different functions like photosynthesis and cellular respiration etc for growth of plants. Both membranes are separated by a space called Intermembrane space commonly known as peri mitochondrial space.
The inner membrane is folded into several fingers known as cristae. Many electron carrier cytochromes are arranged in a definite sequence in the Inner membrane of mitochondria, which forms the Electron transport system (ETS) to help in the respiration of plants. The inner membrane is studded with pinhead particles called oxysomes or elementary particles oF-Particles or ATP Synthase. These particles were first described by Fernandez Moran.
Head of oxysome or F1 is connected with oxidative phosphorylation i.e. formation of ATP by the energy of oxidation.

Hence, the correct answer is option (C).

Note: As cristae are the site of presence of cytochrome so cytochrome oxidase is synthesized by cristae of mitochondria which is present in the inner membrane of eukaryotic organelles i.e mitochondria.