Question

Which one of the following sets is a polysaccharide group?
A) Glucose , fructose , lactose
B) Starch , glycogen , cellulose
C) Sucrose , maltose , glucose
D) Galactose , starch , sucrose

Answer 1

Hint: Carbohydrates are a major source of food and a source of energy for the majority of living organisms. Polysaccharides are one of the most important classes of biomolecules. They are long chains of carbohydrate molecules made up of many smaller monosaccharides.

Complete answer:
Carbohydrates are the most important biomolecule present on earth. It is made up of carbon, hydrogen and oxygen. They are called energy-giving food. The food synthesised in the plants that are glucose is also a carbohydrate.

The carbohydrates are classified into three subtypes-
I) Monosaccharide- It is a simple carbohydrate that is the most basic unit of carbohydrate. For example, glucose, fructose, galactose.

II) Disaccharide- It is a complex carbohydrate that is made up of two monomers of monosaccharide joined by a glucosidic linkage. Example lactose (galactose, glucose), sucrose (glucose, fructose), maltose (2 glucose joined by alpha glycosidic bond).

III) Polysaccharides– These complex bio-macromolecules serve as an important source of energy in animal cells and as a structural component in plant cells. Polysaccharides can be either a straight chain of monosaccharides known as linear polysaccharides or a branched polysaccharide. Example-
i) Starch- The is made up of several glucose molecules joined by a glycosidic bond. The food stored in the plant is in the form of starch.
ii) cellulose -It is made up of several D glucose molecules linked by the beta glycosidic bond. It is an important component of the plant cell wall.
iii) Glycogen- It is a branched polysaccharide that is made up of monomer glucose. The food stored in
the animals is in the form of glycogen.

The correct answer is option (B) i.e, Starch , glycogen , cellulose.

Note: Polysaccharides possess the following characteristics:
- They do not have a sweet taste.
- Many of them are insoluble in water.
- They have a hydrophobic nature.
- It is possible to extract a white powder from it.
- They are carbohydrates with a high molecular weight.
- They are compact and osmotically inactive within the cells.
- They are made up of hydrogen, carbon, and oxygen. The hydrogen-to-oxygen ratio is 2:1.