Plant cell walls are primarily made of cellulose, a complex carbohydrate made up of long chains of glucose molecules. This structure gives the cell wall its strength and rigidity.

Here's a breakdown of the main components:

* Cellulose: The most abundant component, providing the structural integrity.

* Hemicellulose: Another carbohydrate, but with shorter, branched chains. It helps bind cellulose fibers together.

* Pectin: A gel-like substance that helps hold the cell wall layers together and gives it flexibility.

* Lignin: Found in woody tissues, lignin strengthens the cell wall and makes it more water-resistant. It's what gives wood its rigidity.

* Other components: Proteins, lipids, and other small molecules can also be present in smaller amounts.

The specific composition of the cell wall can vary depending on the type of plant and its developmental stage.