You are studying the differences in a particular protein between normal and cancer cells. You find that in the cancer cells the protein is smaller than in the normal cells. Which of the following mutations in the gene encoding the protein would best explain your observations?
A) A to T change in the middle of a long intron in the gene
B) A to T change in the promoter of the gene
C) G to C change in an enhancer found in an intron of the gene
D) missense mutation in the middle of an exon of the gene
E) nonsense mutation in the middle of an exon of the gene

Question

Quizplus · Accepted Answer

A nonsense mutation introduces a premature stop codon, leading to a truncated, and therefore smaller, protein. A nonsense mutation is a point mutation that introduces a premature stop codon into the transcribed mRNA. This results in the synthesis of a truncated and usually nonfunctional protein. It differs from a missense mutation, which is a point mutation where a single nucleotide is changed to cause substitution of a different amino acid at that codon.

You Are Studying the Differences in a Particular Protein Between