Which DNA strand is used as the template to produce mRNA?

Which DNA strand is used as the template to produce mRNA?

• A. Leading strand
• B. Lagging strand
• C. Template strand
• D. Coding strand

Answer: (C)

Transcription uses the antisense, or template, strand of DNA. RNA polymerase reads this template strand in the 3'→5' direction and synthesizes mRNA in the 5'→3' direction, producing a transcript that is complementary to the template strand. The mRNA sequence is essentially identical to the coding (sense) strand, except that RNA uses uracil (U) instead of thymine (T). So the strand used as the template is the one opposite the coding strand, running 3' to 5', which is why the correct choice is the template strand. For example, if the coding strand is 5'-ATG CGA TTA-3', the template strand is 3'-TAC GCT AAT-5', and the resulting mRNA is 5'-AUG CGA UUA-3'.

Transcription uses the antisense, or template, strand of DNA. RNA polymerase reads this template strand in the 3'→5' direction and synthesizes mRNA in the 5'→3' direction, producing a transcript that is complementary to the template strand. The mRNA sequence is essentially identical to the coding (sense) strand, except that RNA uses uracil (U) instead of thymine (T).

So the strand used as the template is the one opposite the coding strand, running 3' to 5', which is why the correct choice is the template strand. For example, if the coding strand is 5'-ATG CGA TTA-3', the template strand is 3'-TAC GCT AAT-5', and the resulting mRNA is 5'-AUG CGA UUA-3'.