Question

The ‘torus’ of simple and bordered pits of the plant cell wall is made up of
A. Phospholipids
B. Cellulose
C. Lignin
D. Cutin

Answer 1

Hint: The basic structure of the cell wall is consisting of primary cell wall middle lamina and plasma membrane. Xylem is made up of tracheid, pits, vessel elements, and parenchyma cells. Xylem helps in the water transporting cells of a plant.

Complete answer: Bordered pits are cavities that are present in the lignified cell walls of xylem, vessels, and tracheid, which are essential components in the water-transport system of higher plants.
1. The pits are the thin areas in the primary cell wall.
2. The type of pits is simple or bordered.
3. The bordered pits are open to the lumen with the thick aperture known as a torus.
4. Torus has a deposition of lignin.
5. It helps to regulate the functional activities of the pit.

Thus, the correct answer is option C. lignin.

Note: Phospholipids are the primary elements of the cell membrane. Cutin is a waxy water-resistant substance that is present in the cuticle of plants, and consists of highly polymerized esters of fatty acids. Cellulose is a branched polysaccharide molecule that is made up of hundreds to thousands of carbon, hydrogen, and oxygen atoms.
Cellulose is the main substance that is present in the cell walls of plants.
It helps plants to remain upright and rigid. Cellulose is very important in the diet of humans as fiber though Humans cannot digest it.
The basic function of the cell wall is protecting the protoplasm of plant cells and provides mechanical support to the plant.