In the process of transcription, what would be the complementary strand of mRNA synthesized from a DNA template strand with the sequence 5'-ATCGTACG-3'?

• A. 5'-UACGUAGC-3'
• B. 5'-UAGCAUGC-3'
• C. 5'-AUCGUACG-3'
• D. 5'-TAGCTACG-3'

Answer: (B)

Verified step by step guidance

1. Understand the process of transcription: Transcription is the synthesis of mRNA from a DNA template. During this process, the enzyme RNA polymerase reads the DNA template strand and synthesizes a complementary mRNA strand.
2. Identify the directionality of the DNA template strand: The given DNA template strand is 5'-ATCGTACG-3'. Transcription reads the DNA template from 3' to 5', synthesizing the mRNA strand in the 5' to 3' direction.
3. Determine the base pairing rules: In transcription, adenine (A) pairs with uracil (U) instead of thymine (T), cytosine (C) pairs with guanine (G), guanine (G) pairs with cytosine (C), and thymine (T) pairs with adenine (A).
4. Apply the base pairing rules to the DNA template strand: For each nucleotide in the DNA template strand, write the complementary mRNA nucleotide using the base pairing rules. For example, A in DNA pairs with U in mRNA, T pairs with A, C pairs with G, and so on.
5. Write the complementary mRNA strand: Using the base pairing rules, convert the entire DNA template strand to its complementary mRNA strand, ensuring the mRNA is synthesized in the 5' to 3' direction.