Question

In polynucleotide chain, a nitrogenous base is linked to ................... through a N-glycosidic linkage to form a nucleoside. Fill the correct update.

• A. The OH of $5^{\prime }C$ pentose sugar
• B. The OH of $1^{\prime }C$ pentose sugar
• C. The OH of $3^{\prime }C$ of pentose sugar
• D. The OH of $5^{\prime }C$ of a nucleoside

Answer 1

The correct option is B The OH of $1^{\prime }C$ pentose sugar

Part 1: Composition of a polynucleotide chain
● A polynucleotide molecule is composed of repeating units of nucleotides.
● Each nucleotide is composed of a nucleoside and a phosphate group attached to it at the $5$’ carbon atom.
● A nucleoside is composed of a pentose sugar and a nitrogenous base attached to the hydroxyl $(-OH)$ group of it $1$’ carbon with the help of a N-glycosidic linkage.


Final answer
(b) The OH of $1^{\prime }C$ pentose sugar