Cellobiose, the hydrolytic breakdown product of cellulose is
A. A monosaccharide
B. A disaccharide
C. A tetrasaccharide
D. A trisaccharide

Hint: The cellulases help in breaking down cellulose into simple sugars which can be fermented into alcohol. They are produced by fungi and bacteria. Cellobiose is a reducing sugar.

Complete Answer:
- Cellulose is a homopolysaccharide of glucose in which the units are linked by beta 1,4 glycosidic bonds. It plays a structural role in plants. It gives rigidity to the cells. The bond between the cellulose molecules is very strong which is difficult to break.
- The hydrolysis of cellulose by the enzyme cellobiohydrolase results in the formation of a disaccharide (made up of two glucose molecules) called cellobiose.
- Cellobiose exists as solid which is soluble in water. It is a very weak acid. Cellobiose occurs naturally and has a significant structural role.
- A monosaccharide obtained from cellulose is glucose.

The correct answer is (B). Cellobiose, the hydrolytic breakdown product of cellulose is a disaccharide.

Additional Information: Cellobiose is similar to cellulose in the glucose content. Cellulose is a non-reducing sugar whereas cellobiose is a reducing sugar. Cellulose is a polysaccharide whereas cellobiose is a disaccharide.

Note: The cellobiose is found in natural foods like pine needles, honey and stems of maize. It gives faint sweetness to food. It is difficult to digest in the human body. It is digested in the small intestine. It is used as an indicator for Crohn’s disease and malabsorption syndrome.