Q.35 Lignin
(A). is a polysaccharide
(B). is second most abundant organic compound
(C). is a polymer of aromatic alcohols
(D). synthetic pathway is peroxidase dependent
Choose the correct answer from the options given below:
1. (A), (B) and (D) only.
2. (A), (B) and (C) only.
3. (A), (B), (C) and (D).
4. (B), (C) and (D) only.
#Lignin MCQ: Correct Answer, Options Explained
Lignin is a key plant cell wall component, and this MCQ tests core facts about its nature and biosynthesis. The correct answer is 4. (B), (C) and (D) only.
What is Lignin?
Lignin is a complex phenolic polymer that provides structural support in vascular plants, second only to cellulose in abundance. It impregnates cell walls, making them rigid and water-impermeable.
Option Analysis
-
(A) is a polysaccharide: Incorrect. Lignin is not a polysaccharide; it is a polyphenolic compound derived from phenylpropanoids, unlike glucose-based polysaccharides like cellulose.
-
(B) is second most abundant organic compound: Correct. Lignin ranks second to cellulose as the most abundant organic material on Earth, comprising 20-30% of lignocellulosic biomass.
-
(C) is a polymer of aromatic alcohols: Correct. Lignin forms through polymerization of monolignols (p-coumaryl, coniferyl, and sinapyl alcohols), which are aromatic alcohols from the phenylpropanoid pathway.
-
(D) synthetic pathway is peroxidase dependent: Correct. Lignin biosynthesis involves peroxidases (and laccases) that oxidize monolignols into radicals for coupling in cell walls.
Why Option 4?
Options (B), (C), and (D) accurately describe lignin’s abundance, composition, and enzymatic synthesis, excluding the false polysaccharide claim in (A).
