In a plant cell, which one of the following contains their own DNA ?
- (a)Nucleus and Endoplasmic Reticulum
- (b)Ribosome and Golgi apparatus
- (c)Mitochondria and Chloroplast
- (d)Chloroplast and Vacuoles
Correct — C, Mitochondria and Chloroplast. These two organelles are 'semi-autonomous': each carries its own small circular DNA and its own ribosomes, so it can make some of its own proteins and divide independently of the nucleus. This is the cornerstone of the endosymbiotic theory. No other listed organelle has its own genome.
- (a)Nucleus and Endoplasmic Reticulum — The nucleus does hold DNA, but the endoplasmic reticulum has no genome of its own — it is a membrane network for synthesis and transport. The pair fails.
- (b)Ribosome and Golgi apparatus — Neither carries DNA. Ribosomes are protein-RNA machines and the Golgi apparatus packages and ships molecules — no genome in either.
- (d)Chloroplast and Vacuoles — The chloroplast does have DNA, but the vacuole (a storage sac) does not, so one member is wrong and the pair fails.
Most of a eukaryotic cell's DNA is in the nucleus, but mitochondria and chloroplasts additionally carry their own circular DNA and 70S ribosomes. Because of this they are called semi-autonomous organelles and can partly self-replicate.
Any correct answer must pair the two DNA-bearing organelles. Options that add the ER, Golgi, ribosome or vacuole include a DNA-less structure and must be wrong. Only 'mitochondria and chloroplast' pairs two genome-carrying organelles.
- Mitochondria and chloroplasts carry their own circular DNA and 70S ribosomes.
- This semi-autonomy underpins the endosymbiotic theory (Lynn Margulis).
- In humans, mitochondrial DNA is inherited maternally.
- The ER, Golgi, ribosomes and vacuoles contain no DNA of their own.
- Pairing a DNA-bearing organelle with the ER, Golgi or vacuole.
- Forgetting the chloroplast (not just the mitochondrion) carries DNA.
Asked directly ('which organelles contain their own DNA') or as an endosymbiotic-theory reasoning item.
Which organelle in the cell, other than nucleus, contains DNA?
- (a) Centriole
- (b) Golgi apparatus
- (c) Lysosome
- (d) Mitochondrion
Answer(d) Mitochondrion
Same concept — which organelle besides the nucleus carries DNA. UPSC's answer is the mitochondrion; this NDA question extends it to the full DNA-bearing pair (mitochondria + chloroplast).
Which of the following organelles have their own DNA and ribosomes?
- (a) Endoplasmic reticulum and Golgi bodies
- (b) Mitochondria and Chloroplast
- (c) Endoplasmic reticulum and cytoskeleton
- (d) Cell wall and nucleolus
Answer(b) Mitochondria and Chloroplast
Near-identical item — the same two semi-autonomous organelles that carry their own DNA and ribosomes.
- practice — not a real PYQ
The presence of their own DNA in mitochondria and chloroplasts is the chief evidence for which theory?
- (a)Cell theory
- (b)Endosymbiotic theory
- (c)Germ theory
- (d)Fluid-mosaic model
Answer(b) Endosymbiotic theory — both organelles descend from once free-living bacteria.
- practice — not a real PYQ
In humans, mitochondrial DNA is inherited
- (a)only from the father
- (b)only from the mother
- (c)equally from both parents
- (d)from neither parent
Answer(b) only from the mother — mitochondria come from the egg.