Plants, on the other hand, aren’t the only ones who have cell walls. Algae, fungi, and the majority of prokaryotes also have cell walls. In terms of structure and chemistry, the cell wall of plants differs from the cell wall of these organisms.

The cell wall in plant cells is made up of two layers: the primary cell wall, which is a thin, flexible, and extensible layer made up of cellulose, pectin, and hemicellulose, and therefore the storage cell wall, which seems to be a thick layer rich in lignin that strengthens and waterproofs the wall and is made inside the first cell membrane that has stopped expanding in surface arches. A middle lamella, a pectin-rich intercellular substance that binds neighboring cells together, lies between the major walls.

Plants rely on their cell walls to help them resist osmotic pressure. The cell wall of bacteria is made up of peptidoglycan, which is necessary for many bacteria to survive. Gram-positive and Gram-negative bacteria are distinguished by the structure of their cell walls. Gram-positive bacteria have a thick cell membrane that’s made from several layers of peptidoglycan and teichoic acids. Gram-negative bacteria have a cell wall that is relatively thin, with only a few layers of peptidoglycan.

Except for a gaggle of methanogens, archaea have cell walls that are made from glycoprotein S-layers, pseudopeptidoglycan, or polysaccharides instead of peptidoglycan. The cell wall of fungus is made up of chitin and other polysaccharides, whereas the cell wall of algae is made up of glycoproteins and polysaccharides, and in some algal species, silicic acid.