Lignin

Lignin is a complex organic polymer that is an integral part of the cell walls of plants. It provides rigidity to the cell walls, allowing plants to stand upright and support their own weight. Lignin is one of the main components of wood, along with cellulose and hemicellulose.

Structure of Lignin

Lignin is composed of phenolic compounds, which are linked together to form a complex three-dimensional network. The exact structure of lignin can vary between plant species, but it generally consists of three main building blocks - coniferyl alcohol, sinapyl alcohol, and p-coumaryl alcohol.

Functions of Lignin

1. Provides structural support to plants
2. Contributes to the rigidity of plant cell walls
3. Makes plants more resistant to microbial attack
4. Helps transport water and nutrients through the plant

Study Guide

1. What is lignin and what is its role in plant cells?
2. Describe the structure of lignin and its main building blocks.
3. Explain the functions of lignin in plants.
4. How does lignin contribute to the strength of wood?
5. Discuss the importance of lignin in the plant's defense mechanisms.