A disaccharide is formed by the chemical bonding of

A) two monosaccharides

B) two polysaccharides

C) one monosaccharide and one polysaccharide

D) All the above

The correct option is A.

Explanation:

A disaccharide refers to a sugar that is formed by the chemical bonding of two monosaccharides which are joined together via glycosidic bond.

A monosaccharide refers to any sugar that can not be reduced further to give a simpler sugar. When two monosaccharides residue come together they form a disaccharide ('Di' means two).

One good example of monosaccharide is glucose. When two glucose molecules or glucose and another monosaccharide join together they give rise to disaccharide such as surcose, lactose and maltose. The components of these disaccharides are given below:

1. Sucrose (Table sugar) : Glucose + fructose.

2. Lactose (Milk sugar) : Glucose + galactose.

3. Maltose: Glucose + glucose.