Question

A polysome is formed by

• A. A cluster of ribosomes
• B. Many ribosomes attached to mRNA
• C. A cluster of ribosomal sub-units
• D. Many mRNAs being attached to a ribosome
• E. Clusters of cistrons

Answer 1

The correct option is B Many ribosomes attached to mRNA

Large clusters of 10 to 100 ribosomes actively translating protein synthesis are called polysomes which makes options C and E incorrect. They are present in both eukaryotic and bacterial cells. The ribosomes in a polysome are connected by a single molecule of mRNA that is being translated simultaneously by many closely spaced ribosomes; option D is incorrect. As soon as translation is terminated, the two ribosomal subunits dissociate from each other and are re-associated during next round of initiation of protein synthesis only; option A is incorrect. The correct answer is B.