Question

Chitin is strengthened by
A. Calcium phosphate
B. Magnesium phosphate
C. Calcium carbonate
D. Magnesium carbonate

Answer 1

Hint: Chitin is a type of structural polysaccharides. These polysaccharides take part in the formation of the structural framework of the cell wall.

Complete Answer:
Polysaccharides are condensation polymers in which monosaccharides are held together through glycosidic linkage. They are colourless and tasteless hence they are called non-sugars. They are concerned with two important functions: structural and storage of energy.

Polysaccharides are of two types based on their composition:
a. Homopolysaccharides
b. Heteropolysaccharides

Polysaccharides are of main three types:
1. Storage
2. Structural
3. Mucopolysaccharides
- Storage polysaccharides reserve the food. For example Glycogen , starch , insulin.
- Structural polysaccharides forming the structural framework of the cell wall in plants and animals. For example chitin and cellulose.
- Chitin is the most abundant organic substance. It is a heteropolysaccharide found as the structural component of the fungal wall and exoskeleton of arthropods.
- In the chitin basic unit is not glucose but nitrogen containing glucose derivative known as N- acetyl glucosamine. Monomers are joined together by 1-4 β linkage.
- Mucopolysaccharides act as cementing layers between cells, connective tissue and cartilages.

Note: Cellulose is the homopolymer of glucose. It constitutes the plant cell wall, paper pulp,cotton fibre etc. cellulose has an unbranched and linear chain.