Structural polysaccharides are complex carbohydrates that provide support and strength to the cells of plants, fungi, and some bacteria. The most well-known structural polysaccharide is cellulose, which forms the cell walls of plants, giving them rigidity and shape. Another important structural polysaccharide is chitin, found in the exoskeletons of arthropods and the cell walls of fungi. These polysaccharides are made up of long chains of sugar molecules linked together. Their unique structures allow them to resist degradation, making them essential for maintaining the integrity of various biological systems. In addition to cellulose and chitin, other structural polysaccharides include pectin and hemicellulose, which also play vital roles in plant structure.