Final answer:
Peptidoglycan is the compound primarily found in bacterial cell walls, consisting of polysaccharide chains cross-linked by unique peptides. This structure is vital for the rigidity and shape of bacterial cells and is targeted by certain antibiotics to treat bacterial infections.
Step-by-step explanation:
The compound commonly found in bacterial cell walls is peptidoglycan. Peptidoglycan is unique to bacteria and is a critical component for maintaining their structural integrity. It is essentially a polymer consisting of sugars and amino acids that forms a mesh-like layer outside the plasma membrane of most bacteria, providing both rigidity and shape. Composed of long polysaccharide chains, primarily N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM), these chains are cross-linked by peptides that contain a mixture of both D- and L-amino acids, a characteristic unusual among proteins.
This structure is crucial for the survival of bacteria, so much so that some antibiotics work by inhibiting peptidoglycan synthesis, effectively weakening the cell wall and leading to the bacteria's death. While cellulose is the main component of plant cell walls and chitin is found in fungi and the exoskeletons of arthropods, peptidoglycan's unique composition confirms its central role in bacterial cell wall structure.