Biology – Classification | e-Consult

Bacteria Cell Walls: Bacteria cell walls are primarily composed of peptidoglycan. Peptidoglycan is a polymer consisting of sugars (N-acetylglucosamine and N-acetylmuramic acid) and amino acids cross-linked to form a mesh-like structure. This provides structural support and protection against osmotic lysis. The thickness of the peptidoglycan layer can vary between different types of bacteria.

Archaea Cell Walls: Archaea cell walls are diverse and lack peptidoglycan. They are composed of various substances, including:

• Pseudopeptidoglycan: Some Archaea possess pseudopeptidoglycan, which is similar to peptidoglycan but with different sugars and linkages.
• Polysaccharides: Many Archaea have cell walls made of polysaccharides, such as glucans or mannans.
• Proteins: Some Archaea have cell walls composed of proteins.

Functional Significance: The difference in cell wall composition is functionally significant. Peptidoglycan provides rigidity and protection in Bacteria. The diverse cell wall compositions of Archaea reflect their adaptation to a wide range of extreme environments. For example, some Archaea have cell walls that provide protection against high temperatures, high salinity, or other harsh conditions. The absence of peptidoglycan in Archaea also makes them targets for antibiotics that specifically target peptidoglycan synthesis in Bacteria.