Question

Select the INCORRECT statement.

• A. UTRs are untranslated additional sequences on mRNA.
• B. UTRs are present only at 5' end on mRNA.
• C. UTRs are present at both 5' and 3' end on mRNA.
• D. UTRs are required for efficient translation.

Hint:

UTR rule: mRNA has two UTRs — one at 5' end and one at 3' end. Both are important for regulation.

Answer 1

The Correct Option is B

Concept:
Untranslated Regions (UTRs) are segments of mRNA that are not translated into protein but play crucial roles in regulation of gene expression and translation efficiency.

Step 1: Understand UTRs. UTRs are present as:
• 5' UTR → Upstream of the start codon
• 3' UTR → Downstream of the stop codon These regions help in stability, transport, and efficient translation of mRNA.

Step 2: Analyze the given options.
• (A) UTRs are untranslated additional sequences on mRNA → Correct \checkmark
• (B) UTRs are present only at 5' end on mRNA → Incorrect, also present at 3' end $\times$
• (C) UTRs are present at both 5' and 3' end on mRNA → Correct \checkmark
• (D) UTRs are required for efficient translation → Correct \checkmark

Step 3: Conclusion. Thus, the incorrect statement is: \[ \text{UTRs are present only at 5' end on mRNA} \]