Consider the following substances : I) Pectin II) Lignin III)Cutin ' IV) Chitin Which of these substances occur in plant cell wall?

The plant cell wall is a complex structure primarily composed of cellulose, hemicellulose, and pectin [t2, t4]. Pectin (I) is a major matrix substance found in the middle lamella and primary cell wall, acting as a cementing agent [t4, t5, t7]. Lignin (II) is a phenolic polymer that impregnates the secondary cell wall, providing mechanical strength and waterproofing [t4, t5, t6]. Cutin (III) is a lipid-based polymer that, while primarily forming the cuticle layer on the plant surface, is also found impregnated within the outer cell walls of the epidermis [t3, t4]. In contrast, Chitin (IV) is a characteristic component of fungal cell walls and arthropod exoskeletons, not plant cell walls [c2, t4]. Therefore, only Pectin, Lignin, and Cutin are constituents of plant cell walls, making option 1 the correct choice.

Sources

1. [1] https://pmc.ncbi.nlm.nih.gov/articles/PMC10429498/
2. [2] https://www.sciencedirect.com/science/article/abs/pii/S1369526606000409
3. [3] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 2: The Invisible Living World: Beyond Our Naked Eye > 2.5 Why Is Cell Considered to Be a Basic Unit of Life? > p. 24