Question

If the base sequence in mRNA is 5' UAC GUA CGU ACG UAC GUA CGU ACG 3' then what will be the sequence of template strands? 

A. 5’ CGT ACG TAC GTA CGT ACG TAC GTA 3'

B. 5' TAC GTA CGT ACG TAC GTA CGT ACG 3’

C. 5' ATG CAT GCA TGC ATG CAT GCA TGC 3’

D. 5’ GTA TAC ACG TGC GTA GTA CAG GCA 3’

Answer 1

Hint: The template strand is always complimentary to the coding strand. Adenine links with Thymine and Uracil (in the case of RNA) with two Hydrogen bonds while Guanine links with Cytosine with three Hydrogen bonds.  

Complete answer: 

As the DNA gets transcribed into a particular segment of RNA, it, therefore, contains complementary nitrogen bases following the given sequence, however for an RNA the nitrogenous base thymine is essentially replaced by Uracil. 

The RNA produced by the method of transcription is what we know as a transcript. 

In DNA, Adenine-Thymine and Guanine-Cytosine pair together aided by the formation of hydrogen bonds between the 2 bases. 

In RNA the nitrogenous base Thymine isn't present, instead, it gets replaced by Uracil, which possesses a very similar structure to Thymine. 

So, the sequence of the template strand will be 5' ATG CAT GCA TGC ATG CAT GCA TGC 3'.

So, the correct answer is option C, 5' ATG CAT GCA TGC ATG CAT GCA TGC 3’.

Note: The complementary base pairing is vital in DNA because it allows the nitrogenous bases to be arranged in an efficient way, in terms of energy expenditure for base pairing; it is essential in forming the helical structure of DNA. It is also important in replication because it allows the semiconservative replication to take place in DNA strands.