Which one of the following is not applicable to RNA?
- Complementary base pairing
- 5' phosphoryl and 3' hydroxyl ends
- Heterocyclic nitrogenous bases
- Chargaff's rule
Answer
(4) Chargaff's rule
Solution
As per NCERT, Chargaff's rule states that in double-stranded DNA the ratio of adenine to thymine and of guanine to cytosine is constant and equal to one: A = T and G = C.
∵ RNA is usually single-stranded, its purines need not equal its pyrimidines, so Chargaff's rule does not apply to RNA.
RNA still has heterocyclic nitrogenous bases (A, G, C, U), a polynucleotide chain with a 5' phosphate end and a 3' hydroxyl end, and complementary base pairing occurs in RNA (e.g. in folded tRNA and during transcription).
Answer: (4)