Question

Identify the sequence of mRNA from the given sequence of coding strand of DNA.
5' T A C G T A G 3'

• A. 5' U T G C U T C 3'
• B. 3' U A C G U A G 5'
• C. 3' U G C U T C 5'
• D. 5' U A C G U A G 3'

Answer 1

Answer: (D)

Protein synthesis is the process of manufacturing protein from DNA involving two steps - transcription and translation. Transcription is the process of making mRNA from the DNA and this mRNA is translated into a long chain polypeptide with help of ribosome and tRNA.
The strand of DNA from which the new mRNA is synthesized is called as template strand or non-coding or anti-sense strand. It is in the 3' $\to$ 5' direction. The mRNA is synthesized on it in the 5' $\to$ 3' with the help of RNA polymerase enzyme which leads in the same direction. The complementary strand of the DNA which is not used for synthesis of mRNA is called coding/sense strand.
The new mRNA sequence will have the same sequence as coding DNA sequence only thymine will be replaced by uracil.
Coding DNA $\to$ 5' T A C G T A G 3'
mRNA $\to$ 5' U A C G U A G 3'