Which one of the following structures is an organelle within an organelle ?
- Mesosome
- Peroxisome
- Ribosome
- ER
Answer
(3) Ribosome
Solution
As per NCERT, the matrix of mitochondria possesses a single circular DNA molecule, a few RNA molecules, ribosomes (70S) and components for protein synthesis; the stroma of chloroplasts also contains 70S ribosomes.
⇒ Ribosomes occur inside mitochondria and chloroplasts, i.e. an organelle within an organelle.
∵ Mesosome is an infolding of the bacterial cell membrane, and peroxisome and ER lie free in the cytoplasm.
Answer: (3)