Question

The ribosome reads mRNA in which of the following direction?

• A. Both 3’ → 5’ and 5’ → 3’
• B. Either 3’ → 5’ or 5’ → 3’
• C. 3’ → 5’ direction only
• D. 5’ → 3’ direction only

Answer 1

Answer:

D. 5’ → 3’ direction only

• Ribosome reads mRNA in the 5’ → 3’ direction only.

• There is a binding site on the ribosome which has some complementarity to Shine-Dalgarno sequence on the mRNA. This Shine-Dalgarno sequence and the start codon are present on the 5’ side of the mRNA.