Complementary messenger RNA strand from the DNA base sequence CTGAC would be __________.

Complementary messenger RNA strand from the DNA base sequence CTGAC would be __________.

• A. CUGAC
• B. CTGAC
• C. CAGUC
• D. GACUG

Answer: (D)

Transcription copies the template DNA strand into RNA using base pairing, with thymine in DNA pairing with adenine in RNA and uracil replacing thymine in RNA. For the DNA sequence CTGAC acting as the template, each base pairs as C→G, T→A, G→C, A→U, C→G. This gives the mRNA sequence GACUG. Note the uracil in RNA replaces thymine. If CTGAC were the coding strand, the mRNA would be CUGAC, but since the request is the complementary RNA strand, the correct result is GACUG.

Transcription copies the template DNA strand into RNA using base pairing, with thymine in DNA pairing with adenine in RNA and uracil replacing thymine in RNA. For the DNA sequence CTGAC acting as the template, each base pairs as C→G, T→A, G→C, A→U, C→G. This gives the mRNA sequence GACUG. Note the uracil in RNA replaces thymine. If CTGAC were the coding strand, the mRNA would be CUGAC, but since the request is the complementary RNA strand, the correct result is GACUG.