When a nucleotide from DNA containing adenine is hydrolyzed, the products obtained are
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Adenine, deoxyribose sugar and phosphoric acid.
A nucleotide has three parts: a nitrogenous base, a pentose sugar and a phosphate group. Base + sugar alone is a nucleoside; adding the phosphate gives the nucleotide. The sugar tells DNA and RNA apart: DNA contains 2-deoxyribose, RNA contains ribose.
So complete hydrolysis of a DNA nucleotide containing adenine gives the base, the sugar and phosphoric acid:
\( \displaystyle \text{deoxyadenosine monophosphate} + \text{water} \rightarrow \text{adenine} + \text{2-deoxyribose} + \ce{H3PO4} \)
Why the other options are incorrect
Option (2) Adenine, ribose sugar and phosphoric acid — Incorrect. Ribose is the sugar of RNA; a DNA nucleotide gives 2-deoxyribose.
Option (3) Adenine and ribose sugar only. — Incorrect. This is the composition of an RNA nucleoside: the sugar is wrong and the phosphate is missing.
Option (4) Adenine and deoxyribose sugar only. — Incorrect. This is the DNA nucleoside (deoxyadenosine); a nucleotide also gives phosphoric acid.
NCERT (2026-27 edition):
Chemical Composition of Nucleic Acids
