Use the Following Model of a Eukaryotic Transcript to Answer

question 43

Multiple Choice

Use the following model of a eukaryotic transcript to answer the question. E1-4 refer to the exons and I1-3 refer to the introns in the pre-mRNA transcript.
5' UTR E1 I1 E2 I2 E3 I3 E4 UTR 3'
Suppose that an induced mutation removes most of the 5' end of the 5' UTR. What might be the result of this removal?

• A) Removal of the 5' UTR has no effect because the exons remain intact.
• B) Removal of the 5' UTR also removes the 5' cap, so the mRNA may be quickly degraded by hydrolytic enzymes.
• C) The 3' UTR will duplicate and one copy will replace the 5' end.
• D) The first exon will not be read because I1 will now serve as the UTR.