Question

Name the chief constituent of cell wall
A. Cellulose
B. Pectin
C. Lignin
D. Suberin

Answer 1

Hint: The plasma membrane of plants, bacteria, and fungus is surrounded by the cell wall, which is the cell's outermost layer. Molds, yeasts, rusts, mushrooms, and other microorganisms are categorised as fungi, which are recognised as a separate kingdom. These are eukaryotic creatures that are heterotrophic and multicellular.

Complete answer:
Option A: The main component of a plant cell's cell wall is cellulose, which is a polysaccharide. Suberin is a waxy material found in plant cell walls, lignin is found mostly in the cell walls of dead plant cells, and pectin is a heteropolysaccharide found solely in the primary cell wall.
So option A is correct.
Option B: Pectin is a heteropolysaccharide that is made up largely of esterified D-galacturonic acid. Pectin is used as a thickening and gelling agent, as well as an emulsifier. Plants have it in their primary and middle lamellae, as well as their cell walls.
So option B is not correct.
Option C: Lignin fills the crevices between cellulose, hemicellulose, and pectin components in the cell wall, particularly in vascular and support tissues such as xylem tracheids, vessel elements, and sclereid cells. Water absorption to the cell wall is hampered by the crosslinking of polysaccharides by lignin.
So option C is not correct.
Option D: The plasma membrane, which is the principal site for cellulose synthesis and the main component of the cell wall, is the boundary of separated protoplasm. The plasma membrane is encased by cell wall components such as lignin and pectin. As a result, the cell wall determines the cell's form.
So option D is not correct.

So option A is the correct answer.

Note:
Carbohydrate-rich components make up the majority of the cell wall. Cellulose, pectins, hemicelluloses, proteins, and phenolics are the main components of the cell wall. The cell wall is a biphasic structure made up of moderately hard cellulose microfibrils embedded in a non-cellulosic matrix that looks like a gel.
The matrix is made up of non-cellulosic polysaccharides and other components like pectins, hemicelluloses, proteins, and phenolics, while the microfibrillar phase is made up entirely of cellulose.