Talk:Cell wall

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    Cell walls hold everything in place. If an organism doesn't have a cell wall, it will have a splat look. Without a cell wall everything would be floating around. you need a picture of a cell wall.

    [edit] Could we get

    A note about turgidity, flaccidity and overinflation within a cell wall? 66.75.246.149 04:17, 22 September 2005 (UTC)

    a cell wall is fully permeable

    [edit] What's the story...

    ...with the image link? Clicking on this link starts the file upload dialogue. Is this a temporary thing? --RunningFree 21:28, 25 October 2005 (UTC)

    It works fine now. Supergrunch 18:15, 7 March 2006 (UTC)


    [edit] (new) more about the Fungal Cell Wall section...

    I am wondering whether maybe this paragraph needs some further adjustment. As far as I understood, fungal cell walls are composed of (from inside out):

    • chitin layer (following the plasmamembrane)
    • a layer of β-1,3-glucan
    • a layer of mannoproteins (= mannose-containing glycoproteins) which are heavily glycosylated towards the outside

    Most of the glucosamine units found in the cell walls are in fact the subunits of chitin, since chitin is a cellulose-like polymer consisting mainly of unbranched chains of N-acetyl-D-glucosamine. Chitin = Polymeric N-acetyl-D-glucosamine

    references:

    "The polyglucose beta-1,3-D-glucan is a major structural component of the cell wall of yeasts and fungi."

    "The fungal kingdom is very diverse, with species growing as unicellular yeasts and/or branching hyphae that produce a remarkable array of spores and other reproductive structures. In each case, the shape and integrity of the fungus is dependent upon the mechanical strength of the cell wall, which performs a wide range of essential roles during the interaction of the fungus with its environment (Gooday, 1995Down). The fungal wall is a complex structure composed typically of chitin, 1,3-{beta}- and 1,6-{beta}-glucan, mannan and proteins, although wall composition frequently varies markedly between species of fungi. For diagrammatic representations of part or all of the cell wall of yeasts or filamentous fungi see recent reviews by Bernard & Latgé (2001)Down, McFadden & Casadevall (2001)Down, Smits et al. (2001)Down and Odds et al. (2003)"

    "The cell wall of Saccharomyces cerevisiae represents some 30% of the total weight of the cell and is made up of beta-glucans, mannose-containing glycoproteins (mannoproteins), and small amounts of chitin. The mannoproteins can be divided into three groups according to the linkages that bind them to the structure of the cell wall: (i) noncovalently bound, (ii) covalently bound to the structural glucan, and (iii) disulfide bound to other proteins that are themselves covalently bound to the structural glucan of the cell wall."


    --Spitfire ch 11:37, 23 April 2007 (UTC)

    http://www.biologie.uni-hamburg.de/b-online/e33/33.htm says that "Constitute oomycetes a missing link or a group that cannot be counted among fungi at all? Oomycetes contain - in contrast to all other fungi – cell walls out of cellulose, their zoospores have two heterokont flagellae, and their thallus resembles that of some siphonal algae (Vaucheria, for example)." (Boldface added by me)and "Both plant and fungal cells are enclosed by a cell wall while animal cells have no such characteristic. This is true, and cell walls exist in prokaryotes (bacteria, blue-green algae), too. The walls of all three mentioned kingdoms have, nevertheless, different molecular compositions (they contain different molecular classes), their biosynthetic pathways and the way of their cellular growths are different. They are therefore not homologous.".

    • However, http://www.iscid.org/encyclopedia/Cell_Wall, says "Fungal cell walls are similar to plant cell walls in that they contain cellulose, but they also contain glucosamine and chitin, both common supplements in herbal remedies for arthritis.", so DO they actually contain cellouse?!
    • Then, http://www.botany.hawaii.edu/faculty/wong/BOT135/Lect03_b.htm says, "The mycelium or yeast cell is surrounded by a cell wall that is typically composed of chitin, the same material that makes up an insect's exoskeleton. However, one group of fungi that we will be studying has cell wall composed of cellulose, which is is the same material that is found in plant cells [...] However, those "fungi" with cellulose cell walls are no longer believed to be closely related to the fungi and have even been classified in a kingdom of their own." (Boldface added by me), so I guess they DON'T count as fungi?
    • Also, http://vilenski.org/science/safari/cellstructure/cellwall.html says "Note: fungal cell walls contain chitin instead of cellulose." Seems to me that fungi DON'T have cellouse cell walls.

    Summary: Fungi DO NOT have cellulose walls. There are "fungi" with cellulose cell walls, but they are not actually fungi. Therefore, I'm going to try to change the paragraph... 169.229.121.94 00:37, 8 December 2006 (UTC)