Question

The bond between $3'$ and $5'$ carbon of pentosed sugar of nucleotide is called

Hint:

Differentiate the key biological bonds:
Nucleotides $\rightarrow$ Phosphodiester bond
Amino acids $\rightarrow$ Peptide bond
Monosaccharides $\rightarrow$ Glycosidic bond

Answer 1

Step 1: Understanding the Concept:
Nucleic acids (DNA and RNA) are polymers composed of repeating monomer units called nucleotides. To form the long polymer chain, these individual nucleotides must be chemically linked together.

Step 2: Key Formula or Approach:
Identify the specific functional groups that react to join adjacent nucleotides and the name of the resulting chemical linkage.

Step 3: Detailed Explanation:
A nucleotide consists of three parts: a nitrogenous base, a pentose sugar, and a phosphate group.
In a nucleic acid chain, nucleotides are joined end-to-end. This connection is formed by a condensation reaction between:
1. The hydroxyl ($-\text{OH}$) group attached to the $3'$ carbon of the pentose sugar of one nucleotide.
2. The phosphate group attached to the $5'$ carbon of the pentose sugar of the adjacent nucleotide.
Because the phosphate group ($PO_4$) forms two ester bonds—one with the $5'$ carbon of its own sugar and a new one with the $3'$ carbon of the next sugar—the resulting connection bridging the two sugars is called a phosphodiester linkage (or phosphodiester bond).
This linkage forms the continuous "sugar-phosphate backbone" characteristic of all DNA and RNA strands.

Step 4: Final Answer:
The bond is called a phosphodiester bond.