Most Archaens lack peptidoglycan<em> </em>a.k.a murein in their cell wall. Peptidoglycans help maintain the strength of the cell wall as well as repel the osmotic pressure in the cytoplasm. A common misconception of the use of peptidoglycans is that it gives the cell shape. However, peptidoglycans only improve the structure of the cell wall by strengthening it.
