Question

For the given sequence of DNA, identify the complementary sequence of bases on its mRNA from the options given below:
DNA 3'-ATGCATGCATGC-5'

• A. 5'-UACGUACGUACG-3'
• B. 5'-TACGTACGTACG-3'
• C. 3'-UACGUACGUACG-5'
• D. 5'-GCATGCATGCAT-3'

Answer 1

The Correct Option is A

DNA Template Strand:

3' - ATGCATGCATGC - 5'
mRNA is synthesized complementary to the template DNA strand.

Base Pairing Rules (DNA → RNA):

• A (DNA) → U (RNA)
• T (DNA) → A (RNA)
• G (DNA) → C (RNA)
• C (DNA) → G (RNA)

Complementary mRNA Sequence:

DNA: 3' - A T G C A T G C A T G C - 5'
mRNA: 5' - U A C G U A C G U A C G - 3'

Answer 2

DNA template strand: 3' – ATGCATGCATGC – 5'

mRNA synthesis follows complementary base pairing (A→U, T→A, C→G, G→C) and 5'→3' direction.

Thus, the mRNA sequence is: 5' – UACGUACGUACG – 3'.

• Option (B) shows DNA (T instead of U).
• Option (C) is reversed (3'→5').
• Option (D) is incorrect pairing.

Correct Answer: (A) 5' – UACGUACGUACG – 3'