Topics:
Animal Nutrition, Animal Refresher
Metabolic Precursor of Lignin
Which of the following is precursor of lignin:
- Tyrosine
- Phenylalanine — Correct Answer
- Hexose
- None
Explanation:
Correct Answer: Phenylalanine
Lignin is a complex, indigestible, three-dimensional phenolic polymer providing rigidity to plant cell walls. In plant biochemistry, its biosynthesis proceeds via the phenylpropanoid pathway, with the aromatic amino acid Phenylalanine as the primary metabolic precursor (converted first to cinnamic acid, then to monolignols, then polymerised into lignin).
Key Metabolic Precursors (from notes)
| Product | Precursor |
|---|---|
| Lignin | Phenylalanine |
| Glucose (ruminants) | Propionate |
| Thyroxin, Catecholamines (Epinephrine, Norepinephrine) | Tyrosine |
| Niacin / Nicotinic acid | Tryptophan |
| Prostaglandins | Arachidonic acid |
| Vitamin D, Steroid hormones | Cholesterol |
| Cholesterol | Acetyl-CoA |
📚 About this Topic — Animal Nutrition
This multiple choice question is from Animal Nutrition, Animal Refresher. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Animal Nutrition to strengthen your preparation.
