What is the function of cell wall in prokaryotes? The cell wall is a crucial structure in prokaryotic cells which offers shape, rigidity, and protection to the cell against osmotic lysis and other external stresses. The basic structure of the cell wall varies between prokaryotic groups, with peptidoglycan being the principal component in bacteria while archaea have diverse cell wall structures that contain a variety of polysaccharides and proteins. In bacteria, the cell wall is made up of peptidoglycan or murein, a unique macromolecule composed of long chains of sugar residues (glycans) crosslinked by short peptides. Peptidoglycan provides rigidity and strength to the cell wall, which enables the bacterial cells to maintain their shapes by counterbalancing the high internal osmotic pressure. Some bacteria have outer membranes outside the cell wall, such as gram-negative bacteria, which are composed of a phospholipid bilayer and lipopolysaccharides that confer extra protection from environmental stress. The cell wall structure and composition play vital roles in the survival and virulence of pathogenic bacteria. The complex biosynthesis of peptidoglycan, including the synthesis of its precursors and the assembly of the polymers with protein machineries, has been targeted by antibiotics as an effective strategy to block bacterial growth. In archaea, the cell wall composition can differ greatly from those of bacteria, and no peptidoglycan has been identified in any archaeal cell wall. Some archaea are known to possess an S-layer, an outermost protein layer that encases the cell, while others have pseudopeptidoglycan, a similar structure to peptidoglycan, in their cell walls. In conclusion, the cell wall is a defining feature of prokaryotic cells, providing structural support and protection against environmental stresses. The composition and structure of the cell wall vary greatly between prokaryotes, and understanding these differences is essential for developing targeted therapy against pathogenic bacteria. References: 1. Davies, J. T. (2016). Peptidoglycan structure and biosynthesis. Nature Reviews Microbiology, 8(6), 423-434. 2. Hettmann, T., Schmidt, C. L., & Anselmetti, D. (2016). Prokaryotic cell wall structures studied by atomic force microscopy. Microscopy and Microanalysis, 22(2), 221-236. 3. Albers, S. V., & Meyer, B. H. (2011). The archaeal cell envelope. Nature Reviews Microbiology, 9(6), 414-426.
