UPSC Prelims 2001 Q126: Science & Technology – Biology
Which organelle in the cell, other than nucleus, contains DNA?
- (a) Centriole
- (b) Golgi apparatus
- (c) Lysosome
- (d) Mitochondrion
Answer: (d) Mitochondrion
Explanation
Cell organelle, other than the nucleus, that contains DNA
| Organelle | DNA? |
|---|---|
| Mitochondrion | Yes — its own circular DNA and ribosomes; inherited from the mother |
| Chloroplast (plants) | Yes — also has its own DNA |
| Centriole | No — helps form the spindle in cell division |
| Golgi apparatus / lysosome | No — packaging / digestion |
Mitochondria carry their own small circular DNA, a sign that they came from bacteria taken into early cells (the endosymbiotic theory). Centrioles, the Golgi apparatus and lysosomes have no DNA.
Answer: (d) Mitochondrion.
Why each option is right or wrong
- (a) Incorrect. Centrioles have no DNA of their own.
- (b) Incorrect. The Golgi apparatus has no DNA.
- (c) Incorrect. Lysosomes have no DNA.
- (d) CORRECT. Mitochondria contain their own DNA.
Key point
Mitochondrial DNA is passed only through the mother, so it is used to trace maternal ancestry.
Remember
DNA outside the nucleus: mitochondria (and chloroplasts in plants).
Common mistakes
- Forgetting that mitochondria have their own DNA.
- Choosing the centriole because it takes part in cell division.
- Thinking DNA is found only in the nucleus.
Exam tip
Semi-autonomous organelles (own DNA): mitochondria and chloroplasts.
Sources
- NCERT Class XI — Biology, chapter 'Cell: The Unit of Life'
- NCERT Class XII — Biology, chapter 'Evolution' (endosymbiosis) / 'Molecular Basis of Inheritance'