The plant cell wall is a rigid outer layer that surrounds the cell membrane of plant cells. It provides structural support, helping the plant maintain its shape and resist external pressures. Composed mainly of cellulose, the cell wall also contains other polysaccharides and proteins that contribute to its strength and flexibility. In addition to providing support, the plant cell wall plays a crucial role in regulating the movement of substances in and out of the cell. It acts as a barrier, protecting the cell from pathogens and environmental stress. The cell wall is essential for plant growth and development, allowing cells to expand while maintaining integrity.