Question

Explain “Wobble Hypothesis” with the help of a suitable diagram.

Answer 1

Hint: Wobble hypothesis explains about the degeneracy of codon. Codons are the triplet nucleotide codes which code for the amino acid. The codes are made up of Adenine, guanine, cytosine and thymine in DNA and Uracil in RNA. For example- AUG codes for methionine.

Complete answer:
The pairing of nucleotide bases are A pairs with T and C pairs with G. This is known as Watson and Crick pairing.
Wobble hypothesis states that the genetic codes are degenerate. It explains that the third base pairing varies with respect to the base at the third position like G may pair with T or U.
The Wobble position of the codon is the third nucleotide. The characteristic of this nucleotide is-

Binding of the codon in an mRNA, the tRNA is much looser in the third position of the codon. Due to this the non-conventional pairing takes place at the third position.

The degeneracy of Codon takes place due to the structure of anticodon in tRNA. The wobble pairing of tRNA anticodon with mRNA proceeds from the 5' end of the codon. The third pairing is less critical once the other bases are paired. This helps in translation of mRNA with fewer tRNAs.

Note: This hypothesis was clearly seen in the E.coli. The wobble base pairs are more thermodynamically stable than the Watson-Crick bases. Wobble pairing is mostly seen in the secondary structure of RNA and plays an important role in the translation of the genetic code.