Which of tho following bond is present between the Sugar and nitrogen base of a nucleoside?

Options

A. Glycosidic bond
B. Ester bond
C. Phosphodiester bond
D. Hydrogen bond

Answer

To determine the type of bond present between the sugar and nitrogen base of a nucleoside, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Nucleosides**:
- A nucleoside is formed when a nitrogenous base (either purine or pyrimidine) is attached to a sugar molecule (ribose in RNA or deoxyribose in DNA).

2. **Identifying the Bond Type**:
- The bond that connects the nitrogenous base to the sugar is crucial to understanding the structure of nucleosides.

3. **Recognizing the N-Glycosidic Bond**:
- The specific bond that forms between the nitrogen atom of the nitrogenous base and the carbon atom (specifically carbon 1) of the sugar is known as an N-glycosidic bond. This is a type of glycosidic bond where nitrogen is involved.

4. **Eliminating Other Bond Types**:
- Other types of bonds mentioned (ester bond, phosphodiester bond, hydrogen bond) do not apply to the connection between the sugar and nitrogen base in a nucleoside:
- **Ester Bond**: Typically found in the formation of phosphodiester bonds in nucleotides.
- **Phosphodiester Bond**: Formed between the phosphate group and the sugar in nucleotides, not nucleosides.
- **Hydrogen Bond**: Found between complementary nitrogenous bases in nucleotides, not between the sugar and base.

5. **Conclusion**:
- The bond present between the sugar and nitrogen base of a nucleoside is the N-glycosidic bond.

### Final Answer:
- The bond present between the sugar and nitrogen base of a nucleoside is the **N-glycosidic bond**.