Question

Which covalent bond is present in nucleic acid?

• A. Peptide bond
• B. Phosphodiester bond
• C. Glycosidic bond
• D. Thymine bond

Hint:

Phosphodiester bonds are highly stable and are hydrolyzed in cells by nucleases during DNA replication, repair, and RNA degradation.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Biopolymers are synthesized by linking monomeric subunits through specific covalent bonds.

Step 2: Detailed Explanation:
- Phosphodiester bonds form the sugar-phosphate backbone of nucleic acids (DNA and RNA).
This covalent linkage connects the 3' carbon of one pentose sugar to the 5' carbon of the adjacent pentose sugar via a phosphate group.
- Peptide bonds link amino acids together to form proteins.
- Glycosidic bonds link sugars together to form carbohydrates and connect nitrogenous bases to pentose sugars in nucleosides.
While glycosidic bonds are present in nucleosides, the primary covalent linkage forming the polymer backbone of nucleic acids is the phosphodiester bond.

Step 3: Final Answer:
The covalent backbone bond in nucleic acids is the phosphodiester bond.