Question

Which of the following is not a part of nucleus?

• A. Nuclear Membrane
• B. Nucleolus
• C. Endosomes
• D. Lysosome

Answer 1

Answer: (C), (D)

Lysosome

The correct option is C and D.

Explanation of correct option:

1. The nucleus is a double-membrane-bound organelle found in all the eukaryotic cells.
2. It is the controlling center of all cellular activities and comprises the genetic material DNA.
3. The lysosome is not a component of the nucleus, it is a separate organelle, exhibiting distinct functions.
4. Lysosomes are membrane-bound organelles, which comprise distinct enzymes, possessing the tendency to dissociate all kinds of biological polymers like nucleic acids, proteins, etc.
5. Apart from this, it also acts against foreign components like viruses and bacteria and helps in the repair of the cell membrane.
6. Endosomes are the intracellular sorting organelles.
7. They are the components of the endocytic membrane transport pathway arising from the Trans Golgi network.
8. They monitor the trafficking of lipids and proteins.
9. They provide an environment for the substance to be sorted before it reaches the degradative lysosome.

Explanation of incorrect options:

Option A:

1. The nuclear membrane is a part of the nucleus.
2. It is a double layer, which surrounds the nucleus of the cell.
3. It functions to distinguish the chromosomes from the cytoplasm and other contents of the cell.

Option B:

1. The nucleolus is an essential part of the nucleus.
2. It is the spherical composition found in the nucleus of the cell whose main role is to generate and align the ribosomes of the cell.
3. It is the site where transcription of ribosomal RNA genes takes place.

Final answer: Endosomes and lysosomes are not a component of the nucleus.