Question

Use the following model of a eukaryotic transcript to answer the question.

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 result?
A. The 3' UTR will duplicate and one copy will replace the 5' end.
B. Removal of the 5' UTR will result in the strand not binding to tRNAs.
C. Removal of the 5' UTR also removes the 5' cap and the mRNA will quickly degrade.
D. Removal of the 5' UTR has no effect because the exons are still maintained.
E. The first exon will not be read because I1 will now serve as the UTR.

Answer 1

Removal of most of the 5' UTR in a eukaryotic transcript could result in the mRNA quickly degrading due to the loss of the protective 5' cap, which also plays a role in translation initiation.

Step-by-step explanation:

In eukaryotic cells, the 5' untranslated region (UTR) is critical for the stability and translation of mRNA molecules. Removal of most of the 5' end of the 5' UTR would likely cause the mRNA to quickly degrade because the 5' cap, which is essential for mRNA stability and ribosome binding, would be removed.

This cap not only protects mRNA from exonucleases but also plays a role in the initiation of translation by helping to recruit the ribosome to the mRNA transcript.Moreover, the 5' UTR often contains regulatory elements that are important for the controlled translation of the mRNA. Thus, the mutation described would not result in a 3' UTR duplication, have an impact on tRNA binding, or cause the first intron to serve as the untranslated region. Such a change could, however, have profound effects on the mRNA's stability and the eventual protein synthesis.