Question

The coding strand of DNA is
5’-AATTCAAATTAGG-3’
What is the sequence of mRNA?
A) 3’-TTAAGTTTAATCC-5’
B) 5’-AAUUCAAAUUAGG-3’
C) 3’-AAUUCAAUUAGG-5’
D) 5’-TTAAGTTTAATCC-3’

Answer 1

Hint: The sequence of mRNA can be identified based on the process of transcription. The direction of transcription and the fact that RNA has uracil instead of thymine can help to determine the sequence of mRNA.

Complete answer: In DNA-based gene expression, transcription is the first step where a segment of DNA is transcribed to form an RNA. This process takes place with the help of an enzyme known as RNA polymerases. This enzyme uses a single-stranded DNA molecule to synthesize a complementary single strand of RNA. This enzyme builds an RNA strand in 5’-3’ direction, by adding new nucleotides to the 3' end. According to the information provided in the question, the DNA coding strand and the RNA synthesized are the same except the RNA strand has uracil instead of thymine.
5’-AATTCAAATTAGG-3’ (The coding strand of DNA) by transcription -> 5’-AAUUCAAAUUAGG-3’
The RNA strand produced as a result of transcription later undergoes another mechanism called translation. The translation is a process that leads to the formation of proteins. In translation, the RNA acts as a template in the process of translation.
Hence, the correct answer is option B.

Note: To determine the gene sequence of mRNA, DNA nucleotides matched up the nucleotides with the complementary RNA. The sequence can also be determined by replacing DNA’s thymine with the uracil. The mRNA is formed by the process of transcription that involves three steps; initiation, elongation, and termination.