Original

Question

TTC
AAG
Mutation 1
ATC
UAG
Mutation
Mutation 3
TCC
AGG
DNA codon mRNA codon
AAA
The table shows a DNA sequence and three types of mutations that can change the DNA sequence. Which mutation will cause translation to stop?
Mutations 1, 2, and 3
Mutation 1 only
Mutation 1 and 3 only
Mutation 2 only

Answer 1

To determine which mutation will cause translation to stop, we need to identify the resulting codons after the mutations. Specifically, we are looking for a change to a stop codon.

In the genetic code, the following are stop codons:

• UAA
• UAG
• UGA

Looking at the mutations you provided:

1. Original DNA codon sequence: TTC → translates to mRNA codon AAG (which codes for the amino acid Lysine).
   • Mutation 1: ATC → UAG (which is a stop codon)
   • Mutation 2: Not provided but not needed for our analysis.
   • Mutation 3: TCC → AGG (which codes for the amino acid Arginine).

From the comparison:

• Mutation 1 results in UAG (stop codon), which causes translation to stop.
• Mutation 3 results in AGG (which does not cause a stop).

Since Mutation 1 leads to the creation of a stop codon, the correct answer is: Mutation 1 only.