Question

Given below are two statements about the nucleus of cell :
Statement (I) : Chromatin netwok mainly consists of ribose nucleic acid.
Statement (II) : Nucleoli in nucleus are rich in RNA.
In light of the above statements, choose the most appropriate answer from the options given below. :

• A. Both Statement (I) and Statement (II) are correct.
• B. Both Statement (I) and Statement (II) are incorrect.
• C. Statement (I) is correct but Statement (II) is incorrect.
• D. Statement (I) is incorrect but Statement (II) is correct.

Hint:

- Chromatin = DNA + Histones (makes up chromosomes).
- Nucleolus = rRNA factory (dense RNA-protein complex inside the nucleus).

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The cell nucleus is the regulatory center of eukaryotic cells, containing genetic material and specialized regions responsible for coordinating cellular activities and ribosome synthesis.

Step 2: Detailed Explanation:
Let us analyze both statements regarding nuclear components:
- Statement (I): Chromatin is a complex of macromolecules found inside the nucleus of eukaryotic cells.
It consists primarily of Deoxyribonucleic acid (DNA), histone proteins, and small amounts of non-histone proteins.
Ribonucleic acid (RNA) is not the main component of chromatin, making Statement (I) incorrect.
- Statement (II): The nucleolus (plural: nucleoli) is a dense, non-membrane-bound structure located within the nucleus.
It is the site of ribosomal RNA (rRNA) transcription, processing, and assembly of ribosome subunits.
Therefore, nucleoli are highly rich in RNA (specifically rRNA) and associated proteins, making Statement (II) correct.
Thus, Statement (I) is incorrect but Statement (II) is correct.

Step 3: Final Answer:
The correct option is (D), as Statement I is false and Statement II is true.