Types of Nucleic Acid Polymerases — NEET Biology

Correct answer: B — S3 and S5 only

This question tests the understanding of the 'RNA World' concept and the distinguishing properties of DNA and RNA. S1: Correct. The NCERT states, 'RNA was the first genetic material. There is now enough evidence to suggest that essential life processes (such as metabolism, translation, splicing, etc.), evolved around RNA.' S2: Correct. The NCERT states, 'Therefore, DNA has evolved from RNA with chemical modifications that make it more stable.' S3: Incorrect. The NCERT explicitly states, 'DNA being more stable is preferred for storage of genetic information.' RNA's reactivity and instability make it less suitable for stable, long-term storage. S4: Correct. The NCERT states, 'The protein synthesising machinery has evolved around RNA.' S5: Incorrect. The NCERT explains, 'Further, 2'-OH group present at every nucleotide in RNA is a reactive group and makes RNA labile and easily degradable.' This makes RNA less stable and more reactive than DNA. Therefore, statements S3 and S5 are NOT correct. This question evaluates the understanding of why RNA is considered central to the evolution of life processes, the evolutionary relationship between RNA and DNA, and the chemical basis for their differing stabilities and preferred functions.