Editing Cell wall (section)

{{Short description|Outermost layer of some cells}}
{{pp-vandalism|small=yes}}
{{Cell biology|plantcell=yes}}
A '''cell wall''' is a structural layer that surrounds some [[Cell type|cell types]], found immediately outside the [[cell membrane]]. It can be tough, flexible, and sometimes rigid. Primarily, it provides the cell with structural support, shape, protection, and functions as a selective barrier.<ref name="Romaniuk">{{cite journal | vauthors = Romaniuk JA, Cegelski L | title = Bacterial cell wall composition and the influence of antibiotics by cell-wall and whole-cell NMR | journal = Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences | volume = 370 | issue = 1679 | pages = 20150024 | date = October 2015 | pmid = 26370936 | pmc = 4632600 | doi = 10.1098/rstb.2015.0024 }}</ref> Another vital role of the cell wall is to help the cell withstand [[osmotic pressure]] and mechanical stress. While absent in many [[eukaryotes]], including animals, cell walls are prevalent in other organisms such as [[fungi]], [[algae]] and [[plants]], and are commonly found in most [[Prokaryote|prokaryotes]], with the exception of [[Mollicutes|mollicute]] bacteria.

The composition of cell walls varies across [[taxonomic groups]], [[species]], cell type, and the [[cell cycle]]. In [[Embryophyte|land plants]], the primary cell wall comprises [[Polysaccharide|polysaccharides]] like [[cellulose]], [[hemicellulose]]s, and [[pectin]]. Often, other [[Polymer|polymers]] such as [[lignin]], [[suberin]] or [[cutin]] are anchored to or embedded in plant cell walls. [[Algae]] exhibit cell walls composed of [[Glycoprotein|glycoproteins]] and [[Polysaccharide|polysaccharides]], such as [[carrageenan]] and [[agar]], distinct from those in land plants. Bacterial cell walls contain [[peptidoglycan]], while [[archaeal]] cell walls vary in composition, potentially consisting of glycoprotein [[S-layer]]s, [[pseudopeptidoglycan]], or polysaccharides. Fungi possess cell walls constructed from the polymer [[chitin]], specifically [[N-acetylglucosamine]]. [[Diatom|Diatoms]] have a unique cell wall composed of [[biogenic silica]].<ref>{{cite book |last1=Rutledge |first1=Ryan D. |last2=Wright |first2=David W. | chapter = Biomineralization: Peptide-Mediated Synthesis of Materials | chapter-url = https://books.google.com/books?id=8y-CKE8_Bi0C&pg=RA2-PT52 | veditors = Lukehart CM, Scott RA | title=Nanomaterials: Inorganic and Bioinorganic Perspectives | publisher=Wiley | series=EIC Books | year=2013 | isbn=978-1-118-62522-4  |access-date=2016-03-14}}</ref>