Question

The mRNA has Untranslated Regions (UTRs):

• A. At 3’ -end beyond Terminator codon
• B. At 5’ -end before AUG
• C. At both 3’ -end and 5’ -end beyond Terminator codon and before AUG respectively
• D. AUG and Terminator codon flanks the UTR

Hint:

UTRs play crucial roles in gene expression regulation.

Answer 1

The Correct Option is C

Untranslated Regions (UTRs) in mRNA:

(A) At 3'-end beyond Terminator codon - Partially correct but incomplete: UTRs exist at both ends of mRNA.

(B) At 5'-end before AUG - Partially correct but incomplete: UTRs are present at both ends.

(C) At both 3'-end and 5'-end beyond Terminator codon and before AUG respectively - Correct: mRNA contains UTRs flanking the coding sequence - the 5' UTR before the start codon (AUG) and 3' UTR after the stop codon.

(D) AUG and Terminator codon flanks the UTR - Incorrect: This reverses the actual relationship (UTRs flank the coding sequence).

The correct answer is (C), as UTRs are regulatory regions present at both ends of mature eukaryotic mRNA.

Answer 2

mRNA (messenger RNA) contains coding regions (codons) that specify amino acids and untranslated regions (UTRs) that do not code for proteins but play regulatory roles. UTRs are located at:

• 5′-UTR : Before the start codon (AUG). This region helps in ribosome binding and translation initiation.
• 3′-UTR : After the stop codon (UAA, UAG, or UGA). This region helps in mRNA stability and translation termination.

Thus, UTRs are present at both the 5′-end (before AUG) and the 3′-end (beyond the terminator codon) .