Which of the following are not membrane-bound ?
- Ribosomes
- Mesosomes
- Lysosomes
- Vacuoles
Answer
(1) Ribosomes
Solution
As per NCERT, ribosomes are non-membrane bound organelles found in all cells; they are made of RNA and proteins.
Lysosomes and vacuoles, on the other hand, are bounded by a membrane (the vacuolar membrane is the tonoplast), and mesosomes are formed by infoldings of the plasma membrane, so they too are made of membrane.
∴ Ribosomes are not membrane-bound.
Answer: (1)