What is the chemical composition of nucleotide?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → A pentose sugar, phosphoric acid and base.
A nucleoside is a base joined to a pentose sugar; linking phosphoric acid at the 5′ position of the sugar gives a nucleotide. So a nucleotide is a pentose sugar, phosphoric acid and a base.
Why the other options are incorrect
Option (2) A hexose sugar, phosphoric acid and base. — Incorrect. The sugar in nucleic acids is a pentose (ribose or deoxyribose), not a hexose.
Option (3) A pentose sugar and base. — Incorrect. A pentose sugar and a base make a nucleoside; the phosphate group is missing.
Option (4) A pentose sugar and phosphoric acid. — Incorrect. The nitrogenous base is missing.
NCERT (2026-27 edition):
Structure of Nucleic Acids
