Specifically, the main carbohydrate in most cell walls is cellulose, a complex polysaccharide made up of long chains of glucose molecules.

Here's a breakdown:

* Plants: Cell walls are primarily made of cellulose, which provides structural support and rigidity.

* Bacteria: Bacterial cell walls are made of peptidoglycan, a complex molecule made of sugars and amino acids.

* Fungi: Fungal cell walls are made of chitin, another complex carbohydrate.

While carbohydrates are the main component of cell walls, other macromolecules like proteins and lipids can also be present in smaller amounts, contributing to the overall structure and function of the cell wall.