CAPF AC 2022 Q12: Science & Technology – Biotechnology & Genetics
- (a) Nucleoid and Chromatin
- (b) Chromatin and Nucleoid
- (c) Nucleoid and Nucleolus
- (d) Nucleolus and Chromatin
Answer: (a) Nucleoid and Chromatin
Explanation
Genetic material in two kinds of cells
How to think: a prokaryote has no true nucleus.
Its DNA lies in an open region called the nucleoid.
A eukaryote has a nucleus with a membrane, and its DNA is packed with proteins as chromatin.
The word respectively means keep that order.
| Feature | Prokaryote | Eukaryote |
|---|---|---|
| Nucleus | Absent | Present, with a membrane |
| Genetic material | Nucleoid: naked circular DNA | Chromatin: DNA with histone proteins |
| Examples | Bacteria, blue-green algae | Plants, animals, fungi |
Do not confuse: the nucleolus is a small body inside the nucleus that makes ribosomes.
It is not the genetic material.
Answer: (a) Nucleoid and Chromatin.
Why each option is right or wrong
- (a) CORRECT. Prokaryotes have a nucleoid and eukaryotes have chromatin.
- (b) Incorrect. This reverses the order asked for by the word respectively.
- (c) Incorrect. The nucleolus makes ribosomes; it is not genetic material.
- (d) Incorrect. Prokaryotes have no nucleolus at all.
Key point
Prokaryote: nucleoid (naked circular DNA, no nuclear membrane). Eukaryote: chromatin (DNA + histones) inside the nucleus; it condenses into chromosomes during cell division. Nucleolus: site of ribosome formation.
Remember
Prokaryote: nucleoid. Eukaryote: chromatin.
Common mistakes
- Mixing up nucleoid (prokaryotic DNA region) with nucleolus (ribosome factory).
- Ignoring the word respectively and choosing the reversed pair.
- Thinking prokaryotes have chromatin with histone proteins.
Exam tip
Educated guess: the ending -oid means resembling. A nucleoid only resembles a nucleus, so it belongs to the cell without a true nucleus, the prokaryote.
Sources
- NCERT Class IX Science — The Fundamental Unit of Life (nucleus, nucleoid)
- NCERT Class XI Biology — Cell: The Unit of Life