Question

Rigidity in the cell wall is due to
A. Cellulose
B. Suberin
C. Lignin
D. Pectin

Answer 1

Hint: An extra structural layer that is found outside the cell membrane that is responsible for providing the structure and support to the cell is called the cell wall. The cell wall is not found in all the organisms. It only occurs in the prokaryotic cells, algal cell, a fungal cell, and plant cells.

Complete answer:
The cell wall is composed of hemicellulose, polysaccharides cellulose, and pectin. The cell wall also possesses some polymers like suberin, lignin, or cutin. Lignin is responsible for providing strength and rigidity to the cell wall of some algae and vascular plants. These cross-linked polymers are a very important component in the formation of the cell wall. Lignin is a hydrophobic compound and comprises a high amount of aromatic compounds.
Cellulose is polysaccharides that form the primary cell wall of algae, plants, and bacteria. The density of the cellulose is 1.5g/cm3. Its main function is to provide structure to the cell wall.
Suberin is found in the specific cell wall of some plants. These are the lipophilic macromolecules. It provides protection and insulation to the plant cell from the environment
Pectin is a heteropolysaccharide that is located in the middle and primary lamella and the cell wall of the plant. Pectin is acidic. It is only found in terrestrial plants. Golgi vesicles are responsible for depositing the pectin into the cell wall via exocytosis.
So, the correct answer is “Option C”.

Note: Cell wall of plant cells comprises three layers. These are primary cell walls, secondary cell walls, and tertiary cell walls. The cell acts as the external protector of the cell and maintains the rigid structure of the cell. Apart from forming the structure, the cell wall sustains the cell shape and is involved in cellular transportation.