The cell wall is the outer covering of the cell. It is typically found in plants and fungi. It is a thick and rigid structure. It provides cell it's structure and shape. It is a protective layer which allows certain molecules to enter and go out of the cell. In plants the cell wall is made up of cellulose, which is a carbohydrate. The cellulose provides the plant cell wall it's rigidity.
Cell walls of plants are made of cellulose. However, some cell walls are made of chitin such as those of fungi. They are thicker then the cell membrane and their structure are rigid. They form a mechanically protective enclave for the cell and give structural strength to a cell.
If the substance will enter the cell by diffusion, the temperature will not change raise inside the cell as the water have high capacity of with standing the temperature changes. Hence water is called as thermal insulator.
