Question

Structures of four disaccharides are given below. Among the given disaccharides, the non-reducing sugar is: 

• A. Maltose
• B. Lactose
• C. Sucrose
• D. Cellobiose

Hint:

To identify non-reducing sugars: - Check if both anomeric carbons are involved in glycosidic linkage. - If yes → non-reducing sugar (e.g., sucrose). - If no → reducing sugar (e.g., maltose, lactose, cellobiose).

Answer 1

The Correct Option is C

The given question requires identifying the non-reducing sugar among the provided disaccharides. Let's examine each disaccharide to determine their reducing or non-reducing nature.
Maltose: It is a reducing sugar since one of the glucose units retains a free anomeric carbon, allowing it to act as a reducing agent.

1. Lactose: This disaccharide also has a free anomeric carbon on one of its sugar units, making it a reducing sugar.
2. Sucrose: This is a non-reducing sugar. In sucrose, the anomeric carbon atoms of glucose and fructose are involved in the glycosidic bond, preventing either from behaving as a reducing agent.
3. Cellobiose: Similar to maltose and lactose, cellobiose has a free anomeric carbon, which classifies it as a reducing sugar.

Conclusion: Among the options, Sucrose is identified as the non-reducing sugar. This is because both anomeric carbons participate in the glycosidic bond, eliminating free anomeric carbons in either glucose or fructose units.