Question

Which of the following mRNA is translated completely.
(A) 5' AUG UGA UUA AAG AAA 3'
(B) 5' AUG AUA UUG CCC UGA 3'
(C) 5' AGU UAG AGA CUC UAA 3'
(D) 5' AUG UAC AGU AAC UAG 3'

• A. (A) and (B)
• B. (B) and (D)
• C. (C) and (D)
• D. (A) and (D)

Answer 1

The correct option is B (B) and (D)

• A translation unit of mRNA carries a sequence of start codon AUG (coding for N-formylmethionine in prokaryotes and methionine in eukaryotes), codons for polypeptide, and a stop codon (UAA, UAG and UGA).
• Hence, a mRNA sequence that contains a start codon and a termination codon with intermediate codons will be translated.
• Checking the sequences given in the question we see, only options B and D fulfill this criteria because in A and C there are stop codons present within the mRNA sequence. Hence mRNA sequences given in options A and C can't complete translation.

Therefore, the correct answer is "(B) and (D).