Question

What would not happen if the RNA strand is completely removed from RNA: DNA hybrid?

(a) There are no chances of the synthesis of the second DNA strand

(b) Chance complementarity would take place

(c) Hairpin structure would be formed

(d) Hairpin structure is formed is not the final structure

This question was posed to me in an interview for internship.

This is a very interesting question from cDNA Libraries, Polyadenylated RNA and cDNA Synthesis topic in chapter Libraries Construction of Genetic Engineering

Answer 1

Correct choice is (a) There are no chances of the synthesis of the second DNA strand

The explanation is: If the RNA strand is completely removed from RNA: DNA hybrid, the single stranded DNA remains. Then chance complementarity takes place and the 3’ end complements with any other portion in the single stranded DNA. It leads to the formation of a hairpin structure and the 3’ end extends in the presence of DNA pol and nucleotides.