Editing Cell wall (section)

===Permeability===
The primary cell wall of most [[plant cell]]s is freely permeable to small molecules including small [[Protein|proteins]], with size exclusion estimated to be 30-60 [[Atomic mass unit|kDa]].<ref>{{cite book |author1=Harvey Lodish |author2=Arnold Berk |author3=Chris A. Kaiser |author4=Monty Krieger |author5=Matthew P. Scott |author6=Anthony Bretscher |author7=Hidde Ploegh |author8=Paul Matsudaira |title=Loose-leaf Version for Molecular Cell Biology |url=https://books.google.com/books?id=0bUVAAAAQBAJ |date=1 September 2012|publisher=W. H. Freeman|isbn=978-1-4641-2746-5}}</ref> The pH is an important factor governing the transport of molecules through cell walls.<ref>{{cite book | first = C. Michael | last = Hogan | date = 2010 | chapter-url = http://www.eoearth.org/article/Abiotic_factor?topic=49461 | chapter = Abiotic factor | title = Encyclopedia of Earth | veditors = Monosson E, Cleveland C | publisher = National Council for Science and the Environment  | location = Washington DC | archive-url = https://web.archive.org/web/20130608071757/http://www.eoearth.org/article/Abiotic_factor?topic=49461 | archive-date = 2013-06-08 }}</ref>