NEETZoologyBiotechnology - Principles and Processes
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): During the first step of PCR, the reaction mixture is heated to 94-96^ C to break the hydrogen bonds between the two strands of template DNA. Reason (R): Taq polymerase is a thermostable enzyme that can withstand the high temperatures of the denaturation step. In the light of the above statements,
Options
- ABoth (A) and (R) are true and (R) is the correct explanation of (A).
- BBoth (A) and (R) are true but (R) is not the correct explanation of (A).
- C(A) is true but (R) is false.
- D(A) is false but (R) is true.
Correct answer
B. Both (A) and (R) are true but (R) is not the correct explanation of (A).
Step-by-step solution
Assertion (A) is true: The first step of PCR is denaturation, which involves heating the reaction mixture to 94-96^ C . This high temperature provides the energy required to break the weak hydrogen bonds between the nitrogenous bases of the two DNA strands, separating them into single strands. It does not break the strong covalent phosphodiester bonds of the DNA backbone. Reason (R) is true: Taq polymerase, isolated from the thermophilic bacterium Thermus aquaticus, is thermostable and remains active despite the hi