Zellwände

Zellwände, or cell walls, are rigid outer layers found in plant cells, fungi, algae, and bacteria. They provide structural support and protection to the cell, maintaining its shape and preventing excessive water uptake. The composition of cell walls varies significantly between different organisms. In plants, the primary component is cellulose, a complex carbohydrate. As plant cells mature, they can develop a secondary cell wall inside the primary wall, which is often thicker and contains lignin, a complex polymer that provides rigidity and strength. Fungal cell walls are typically made of chitin, another polysaccharide, while bacterial cell walls are composed of peptidoglycan. Algal cell walls can have diverse compositions, including cellulose, glycoproteins, or even silica. The presence and structure of a cell wall are crucial for the survival and function of these organisms, influencing their interactions with the environment and with other cells. For instance, the rigid cell wall of bacteria contributes to their resistance against osmotic lysis. In plants, the collective action of cell walls in tissues provides the structural integrity of the entire organism, allowing for upright growth.