Question

The genetic codes are degenerative in nature. The degeneracy is observed primarily in the-

• A. 1st base of the codon
• B. 2nd base of the codon
• C. Both 1st and the 2nd base of the codon
• D. Both 3rd and the Wobble position base of the codon

Hint:

Wobble pairing reduces the minimum number of tRNAs required for protein synthesis from 61 to around 31, providing a buffer against deleterious single-point mutations at the third codon base.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The genetic code is described as "degenerate" or redundant because a single amino acid can be specified by more than one codon.
Of the 64 possible codons, 61 code for the 20 standard amino acids, meaning several codons share coding responsibility.

Step 2: Detailed Explanation:
The degeneracy of the genetic code is not randomly distributed; it occurs in a highly organized pattern primarily at the third nucleotide position of the codon.
For many amino acids, the first two nucleotides of the codon are strictly conserved, while the third position can vary without changing the amino acid translated.
According to the Wobble Hypothesis proposed by Francis Crick, the base-pairing rules between the first two positions of the codon and the anticodon on the tRNA are highly specific.
However, the base-pairing at the third position (the wobble position) is chemically flexible, allowing non-canonical pairing interactions (such as G pairing with U).
This wobble pairing allows a single tRNA molecule with a specific anticodon to recognize and bind to multiple different codons on the mRNA.
Thus, the degeneracy of the genetic code is concentrated at both the 3rd base position of the codon and the wobble position.

Step 3: Final Answer:
Therefore, genetic code degeneracy is primarily observed in both the 3rd base and the wobble position base of the codon.