Editing Cell wall (section)

===Formation===
The [[middle lamella]] is laid down first, formed from the [[cell plate]] during [[cytokinesis]], and the primary cell wall is then deposited inside the middle lamella.{{clarify|reason=how can this be, since the middle lamella is defined as the pectic material between the primary cell walls?|date=September 2016}} The actual structure of the cell wall is not clearly defined and several models exist - the covalently linked cross model, the tether model, the diffuse layer model and the stratified layer model. However, the primary cell wall, can be defined as composed of [[cellulose]] [[microfibrils]] aligned at all angles. Cellulose microfibrils are produced at the plasma membrane by the [[cellulose synthase (UDP-forming)|cellulose synthase complex]], which is proposed to be made of a hexameric rosette that contains three cellulose synthase catalytic subunits for each of the six units.<ref>{{cite journal | vauthors = Jarvis MC | title = Cellulose biosynthesis: counting the chains | journal = Plant Physiology | volume = 163 | issue = 4 | pages = 1485–6 | date = December 2013 | pmid = 24296786 | pmc = 3850196 | doi = 10.1104/pp.113.231092 }}</ref> Microfibrils are held together by hydrogen bonds to provide a high tensile strength. The cells are held together and share the gelatinous membrane (the middle lamella), which contains [[magnesium]] and [[calcium]] [[pectate]]s (salts of [[pectic acid]]). Cells interact though [[plasmodesma]]ta, which are inter-connecting channels of cytoplasm that connect to the protoplasts of adjacent cells across the cell wall.

In some plants and cell types, after a maximum size or point in development has been reached, a ''secondary wall'' is constructed between the plasma membrane and primary wall.<ref>{{Cite book| title=Biology| url=https://archive.org/details/essentialbiology00camp_0| url-access=registration|last1=Campbell |last2=Reece |last3=Urry|last4=Cain|last5=Wasserman|last6=Minorsky|last7=Jackson|first1=Neil A.|first2=Jane B.|first3=Lisa A. |first4=Michael L. |first5=Steven A.|first6=Peter V.|first7=Robert B. | name-list-style = vanc |edition=8th|isbn=978-0-8053-6844-4 |pages = [https://archive.org/details/essentialbiology00camp_0/page/119 119] |year=2008| publisher=Pearson Benjamin Cummings}}</ref> Unlike the primary wall, the cellulose microfibrils are aligned parallel in layers, the orientation changing slightly with each additional layer so that the structure becomes helicoidal.<ref name=Abeysekera>{{cite journal | vauthors = Abeysekera RM, Willison JH |title=A spiral helicoid in a plant cell wall |journal=Cell Biology International Reports |volume=11 |issue=2 |date=1987 |pages=75–79 |doi=10.1016/0309-1651(87)90106-8 |doi-broken-date=24 March 2025 }}</ref> Cells with secondary cell walls can be rigid, as in the gritty [[sclereid]] cells in [[pear]] and [[quince]] fruit. Cell to cell communication is possible through [[pit (botany)|pits]] in the secondary cell wall that allow plasmodesmata to connect cells through the secondary cell walls.