Question

The type of bond represented by the dotted line ‘------’ in a schematic polynucleotide chain is:

• A. Hydrogen bond
• B. Peptide bond
• C. N-glycosidic linkage
• D. Phosphodiester bond

Hint:

Sugar and base are connected via N-glycosidic linkage; phosphate-sugar backbone is formed via phosphodiester bonds.

Answer 1

The Correct Option is C

In a polynucleotide structure, each nucleotide consists of a phosphate group (P), a sugar (S), and a nitrogenous base (B).
The dotted line in the figure represents the connection between the sugar (S) and the base (B).
This bond is known as the N-glycosidic linkage, which connects the 1' carbon of sugar to the nitrogen atom of the base.
Let’s briefly compare with other options:
- Hydrogen bond – forms between complementary nitrogen bases of two DNA strands.
- Peptide bond – links amino acids in proteins.
- Phosphodiester bond – links the phosphate of one nucleotide to the sugar of another nucleotide (in the DNA backbone).
Since the question highlights the bond between sugar and base, the answer is N-glycosidic linkage.