What is true about ribosomes ?
- These are self-splicing introns of some RNAs.
- These are found only in eukaryotic cells
- These are composed of ribonucleic acid and proteins
- The prokaryotic ribosomes are 80 S, where 'S' stands for sedimentation coefficient.
Answer
(3) These are composed of ribonucleic acid and proteins
Solution
As per NCERT, ribosomes are the granular structures first observed by George Palade (1953); they are composed of ribonucleic acid (RNA) and proteins and are not surrounded by any membrane. ⇒ (3) is correct.
(1) Self-splicing introns are ribozymes, not ribosomes.
(2) Ribosomes are found in both prokaryotic and eukaryotic cells.
(4) Prokaryotic ribosomes are 70S; eukaryotic ribosomes are 80S.
Answer: (3)