Example 1 below is a strand of DNA and mRNA used to make a protein. Example 2 below is the same DNA but a mutation has occurred. Use the mRNA strand and the codon chart below to determine the outcome in Example 2 compared to Example 1.

Question

Codon Chart:

(1 point)
Responses

Although a mutation has occurred, the codon in Example 2 (CAC) still makes the same amino acid (His) as the codon in Example 1 (CAU). No change will occur.

The mutation also causes a change in the mRNA, so it will always make a new protein.

A mutation in DNA will not cause a change in mRNA.

The mutation has made the middle codon a stop codon.

Answer 1

To compare Example 1 and Example 2, let's examine the specific mutations and their effects on the mRNA and subsequently on the amino acids being produced.

1. If both Example 1 in the mRNA has the codon CAU (which codes for Histidine) and Example 2 has a mutation resulting in the codon CAC (which also codes for Histidine), then the outcome is:

"Although a mutation has occurred, the codon in Example 2 (CAC) still makes the same amino acid (His) as the codon in Example 1 (CAU). No change will occur."

This response indicates that the mutation is a synonymous mutation, causing no change in the protein produced.

2. If the mutation in Example 2 results in a different mRNA codon that changes the amino acid sequence, it might be one of the other responses offered. However, based on the information given and the codon chart for Histidine, the correct response regarding the original codons (CAU and CAC both produce histidine) is the first one.

Thus, unless additional details indicate a different outcome, the most accurate selection is the first response regarding the nonsignificant effect of a synonymous mutation.