What is the Difference Between Lignin and Cellulose?

Lignin and cellulose are both organic compounds found in the cell walls of plants, providing structural rigidity and strength. However, they have distinct differences in their composition, structure, and function:

1. Composition: Cellulose is a polymer made of glucose molecules, while lignin is a polymer made of phenol molecules. The monomer of cellulose is D-glucose, while the three main types of lignols, which are the monomers of lignin, are paracoumaryl alcohol, coniferyl alcohol, and sinapyl alcohol.
2. Structure: Cellulose is a linear structure with linear β glucose chains, while lignin is a three-dimensional, cross-linked polymer. Cellulose is a straight-chain polymer, whereas lignin is an irregular polymer.
3. Location in Plant Cells: Cellulose is present in the primary cell wall, while lignin is present in the secondary cell wall. Cellulose makes up the cell walls of plant cells, while lignin provides rigidity to plants.
4. Function: Cellulose is involved in the primary growth of plants, while lignin is involved in the secondary growth. Lignin also helps in preventing rotting and provides rigidity to plants.
5. Occurrence: Cellulose is the most abundant organic polymer found on Earth, and it constitutes 90% of cotton fiber and 40-50% of wood. Lignin is the second most abundant organic polymer found on Earth.

Comparative Table: Lignin vs Cellulose

The main difference between lignin and cellulose lies in their composition, structure, and function in plant cells. Here is a table comparing the two:

Lignin is a complex, non-carbohydrate aromatic polymer found in plant cell walls, providing rigidity and strength, especially in bark and wood. On the other hand, cellulose is a glucose polymer and the most abundant organic compound on Earth, found in plant cell walls and constituting 33% of all plant matter.