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Moderate

Substitution Mutation

APBIO-EEJJGS

A substitution mutation occurs in a gene coding for an enzyme.

Which of the following choices is the MOST unlikely result?

A

The mutation produces a codon that codes for the same amino acid as the original. The enzyme protein's structure is unchanged.

B

The mutation produces a codon that codes for an amino acid with similar chemical properties to the original (ex. polar, nonpolar, etc.), resulting in a enzyme with the same function as the original.

C

The mutation produces a stop codon in place of a codon for the placement of an amino acid. This produces a protein that is shorter than the original and a nonfunctional enzyme.

D

The mutation produces a codon that codes for an amino acid with different chemical properties than the original. The enzyme now catalyzes a different reaction than the original.