NEETZoologyMolecular Basis of Inheritance
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): Viruses having RNA genome and shorter life span mutate and evolve faster. Reason (R): The 2'-OH group present at every nucleotide in RNA makes it labile, catalytic and prone to faster mutation. In the light of the above statements, choose the most appropriate answer from the options given below:
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
A. Both (A) and (R) are true and (R) is the correct explanation of (A).
Step-by-step solution
According to NCERT, viruses having an RNA genome and a shorter life span mutate and evolve faster. This is because RNA is unstable and mutates at a faster rate. The primary biochemical reason for this instability is the presence of a reactive 2'-OH group on the ribose sugar of every nucleotide, which makes RNA labile and easily degradable. RNA is also known to be catalytic, hence reactive. Therefore, both Assertion (A) and Reason (R) are true, and (R) is the correct explanation of (A). Answer: Both (A) and (R) are