Question

In the structure of a nucleoside, the base is attached to the sugar at which position?

• A. 1'-position
• B. 2'-position
• C. 3'-position
• D. 4'-position

Hint:

Nucleoside: base + sugar.
Glycosidic bond at 1'-position.
Nucleotide: nucleoside + phosphate.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Nucleosides consist of a nitrogenous base attached to a sugar.
The attachment involves a specific bond.

Step 2: Key Formula or Approach:
No specific formula.
Need to know the structure of nucleosides.

Step 3: Detailed Explanation:
In a nucleoside, the nitrogenous base is attached to the sugar.
The bond is between the base (N-1 of pyrimidines or N-9 of purines) and the 1' carbon of the sugar.
This is called a glycosidic bond.
Thus, the base is attached at the 1'-position of the sugar.

Step 4: Final Answer:
The base is attached to the sugar at the 1'-position.
Hence, the correct option is (A).