Question

Cellulose content is high in
A. Primary wall
B. Secondary wall
C. Tertiary wall
D. Middle lamella

Answer 1

Hint: Cellulose gives strength and rigidity to the cell. It makes the wall of plant cells. It is present in walls that are thinner and less rigid than those of cells that have stopped growing.

Complete answer: The cell wall in plants is made up of cellulose. Cellulose is a homopolymer of glucose. The glucose monomers are linked to each other by glycosidic linkages. It provides strength and rigidity to plant cells. The cell wall is not a single layer. It is composed of 3 layers. They are;
a) Primary wall – It is composed mainly of cellulose. It has higher cellulose content than any other cell walls.
b) Secondary wall – It is mainly composed of hemicellulose and pectin.
c) Middle lamella – It is mainly composed of pectins.
The plant cell wall is of utmost importance to plants as it provides the cells with rigidity and control over turgor pressure. The inflow of water into the cells might cause cells to burst if the cell wall is not present. Cellulose, polysaccharide containing repeated unbranched β (1-4) D-glucose units, is synthesized at the plasma membrane by the cellulose synthase complex (CSC) from bacteria to plants. It is one of the widely used natural substances for commercial purposes.
Hence, the correct answer is option A.

Additional information: Algal cell walls are made of carrageenan and agar. Similarly, the cell walls of bacteria are made of peptidoglycan and that of archaea have varied compounds as a part of their cell walls. These compounds are; glycoproteins, s layers, pseudopeptidoglycan and polysaccharides Apart from this, fungi also have a cell wall. Their cell walls are made of chitin. Chitin is a polymer of N – acetyl glucosamine.

Note: The cell wall of plants does not have any layer which is named as a tertiary wall. Diatoms have a cell wall which is composed of biogenic silica. They form the base of coral reefs and are also known as diatomaceous earth.