Question

The fifth C becomes U

Met Lys Leu Ser Arg Val Phe Tyr

AUGAAA CUUUCA CGCGUUUUCUAU




The third U becomes A.

Met Leu Iso Leu Thr Leu Leu Val

AUGUUGAUA CUUACA CUUCUGGUC


what will be mutated mRNA and acids of these sequences?

Answer 1

1. The mRNA sequence with the mutant C:

AUGAAA CUUUCA CGCGUUUUUUAU

This mutation results in the substitution of codon UUC by codon UUU. As both codons encode the same amino acid phenylalanine (Phe), the amino acid sequence is not changed:

Met Leu Iso Leu Thr Leu Leu Val

2. If the third U becomes A, the mRNA sequence is as following:

AUGUAGAUA CUUACA CUUCUGGUC

Mutant codon UAG is a stop codon. As a result, the mRNA cannot be translated as the second triplet encodes a stop codon.