Question

Suppose the third base in the codon CUC is accidentally changed from C to G so that the codon reads CUG. What kind of mutation has occurred?

a. a silent mutation

b. a missense mutation

c. a frameshift mutation

d. a nonsense mutation

Answer 1

Answer: The correct answer is- A) silent mutation.

Mutation can be described as a permanent change in the nucleotide sequence of DNA (deoxyribonucleic acid), which is considered as the genetic material of life forms.

Silent mutation is a type of point mutation in which change in one nucleotide sequence of DNA does not cause any change in the amino acid sequence of the protein that is produced by the DNA.

This is because of the fact that more than one codon (sequence of three nucleotide coding for an amino acid) can code for a particular amino acid.

In this question, CUC is changed to CUG after point mutation. Both of these codons code for the same amino acid that is leucine.

Therefore, it will not bring any change in the amino acid sequence of protein.

Thus, a silent mutation has occurred.