Question

Which one of the following statements is true for protein synthesis (translation)?

(a) Amino acids are directly recognized by m-RNA.

(b) The third base of the codon is less specific.

(c) Only one codon codes for an amino acid.

(d) Every t-RNA molecule has more than one amino acid attachment.

Answer 1

The correct option is: (b) The third base of the codon is less specific.

Explanation:

Genetic code shows degeneracy i.e., occurrence of more than 1 codon per amino acid. All the amino acids except methionine and tryptophan are coded by more than 1 codon. 

For example, valine is specified by GUU, GUC, GUA, GUG. 

This shows that first two bases are common in all the four codons coding for valine. But the third base can be changed.