Which one of the following is correct regarding nucleic acids?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Complete hydrolysis of DNA yields a pentose sugar, phosphoric acid and a nitrogenous base.
Nucleic acids (DNA and RNA) are long chains of nucleotides. Each nucleotide has three parts: a pentose sugar, a phosphate group and a nitrogenous base.
Why the other options are incorrect
Option (2) In DNA molecules, the sugar moiety is D-ribose — Incorrect. The sugar in DNA is 2-deoxy-D-ribose; D-ribose is the sugar of RNA.
Option (3) Adenine, Guanine, Cytosine and Uracil are the four bases present in DNA molecules — Incorrect. DNA contains thymine, not uracil; uracil is found in RNA.
Option (4) Adenine forms hydrogen bonding with Guanine, whereas Cytosine forms hydrogen bonding with Uracil — Incorrect. In DNA, adenine pairs with thymine and guanine pairs with cytosine. Two purines (A and G) never pair with each other.
NCERT (2026-27 edition):
Chemical Composition of Nucleic Acids
