This question is describing the occurrence of the process of mutation, which is the alteration in the genetic sequence of a gene. In this question, a DNA sequence was given as follows: TAC-ATC-CAT-CAG-TTA-CGC. However, a SUBSTITUTION MUTATION took place in such a way that the thymine base was replaced by a guanine base to have mutated sequence: GAC-ATC-CAT-CAG-TTA-CGC.
Since the mutation is a kind of substitution mutation, only the codon affected by that mutation will change. This DNA sequence will be transcribed into a mRNA sequence. The mRNA will be read codon by codon (a group of hree nucleotides) to produce amino acid. Since one codon will be involved, one amino acid will be affected.
