The cell wall is a rigid outer layer found in plant cells, fungi, and some bacteria. It provides structural support and protection. The main components of the cell wall include cellulose, a carbohydrate that forms a strong framework, and hemicellulose, which helps bind cellulose fibers together. In fungi, the cell wall is primarily made of chitin, while in bacteria, it often contains peptidoglycan. In addition to these primary components, the cell wall may also contain lignin in woody plants, which adds strength and rigidity. Other substances, such as pectin, contribute to the wall's flexibility and help in cell adhesion. Together, these components enable the cell wall to perform its essential functions in various organisms.