Question

A single nucleoside consists of________

• A. Sugar + Nitrogenous base
• B. Nitrogenous base + Phosphate group
• C. Sugar + Phosphate
• D. Sugar + Nitrogen base + Phosphate

Answer 1

The correct option is A

Sugar + Nitrogenous base

A nucleoside has two components - a pentose sugar (deoxyribose in DNA and ribose in RNA) and a nitrogenous base. When a phosphate ion gets attached to the sugar, the entire unit is called a nucleotide. So, the difference between the nucleoside and the nucleotide lies in the presence or absence of phosphate ion.