Question

Which of the following statements regarding mitochondria is incorrect?

• A. An Outer membrane is permeable to monomers of carbohydrates, fats and proteins.
• B. Enzymes of electron transport are embedded in the outer membrane.
• C. Inner membrane is convoluted with infoldings.
• D. Mitochondrial matrix contains a single circular DNA molecule and ribosomes.

Answer 1

The correct option is B

Enzymes of electron transport are embedded in the outer membrane.

The correct option is option B.

Explanation of correct option:

1. A semi-autonomous membrane, which is a bounded organelle present in the cytoplasm of several eukaryotic cells is mitochondria.
2. It is known as the powerhouse of the cell, as it is responsible for the generation of energy within the cell.
3. Within the mitochondria, the enzymes like ATP synthase needed for electron transport are found in the inner membrane, not in the outer membrane.
4. An array of four protein complexes, and a couple of redox reactions, result in the formation of an electrochemical gradient, which further results in the generation of ATP in the electron transport chain.

Explanation of incorrect options:

Option A:

1. The outer membrane is a simple phospholipid bilayer, which comprises protein compositions known as porins that assists the molecules of size less than 10 kilo Daltons to pass through it.
2. An outer membrane is permeable to monomers of fats, carbohydrates, and proteins.

Option C:

1. The inner membrane of mitochondria is permeable only to oxygen, water, and carbon dioxide.
2. Its structure is highly convoluted as it folds and produces finger-like projections known as cristae.
3. This crista enhances the total surface area of the inner membrane for the generation of energy in the form of ATP.

Option D:

1. Mitochondria is a semi-autonomous cell organelle, which comprises its genetic material and ribosomes.
2. Within the mitochondria, genetic material is present in the form of circular DNA molecules.

Final answer: Within the mitochondria, the enzymes of electron transport are not embedded in the outer membrane.