Final answer:
Bacterial cell walls differ from plant and fungal cell walls in their composition. Bacteria have peptidoglycan-based cell walls, while plants use cellulose and fungi use chitin as their primary structural component. The complexity of bacterial cell walls also varies between Gram-positive and Gram-negative bacteria.
Step-by-step explanation:
The molecular structure of bacterial cell walls significantly differs from those of plants or fungi. Bacterial cell walls are primarily composed of peptidoglycan, which consists of long chains of alternating molecules of N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM). These chains are connected with peptide bridges, providing strength to the cell wall.
On the other hand, plant cell walls are chiefly made up of cellulose, a polysaccharide consisting of glucose units. This cellulose provides the rigid structure that, for example, gives the crunch when biting into a raw vegetable such as celery. Fungal cell walls, however, contain chitin, a different structural polysaccharide.
Bacteria are categorized into Gram-positive and Gram-negative groups based on their cell wall structure. Gram-positive bacteria have a thick peptidoglycan layer, while Gram-negative bacteria have a thinner peptidoglycan layer and an additional outer membrane containing lipopolysaccharides and lipoproteins.