The Structure of Cell Membranes

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In 1871 Hugo de Vries cell membrane permeability for ammonia and glycerol, this was leading upto the first successful X-ray study by Bernal and Crowfoot in 1934 of the globular protein pepsin, however even though it shows water covering the protein surface, it doesn’t show it in high resolution. Many years has past with more testing and experiments but it wasn’t until 1925 when E, Gorter and F, Grendel proposed the phospholipid layers in the cell membrane which resulted in them doing first bilayer structure experiment test, obtaining this by measuring the size of water surface that phospholipids taken from red blood cell can cover, the area in which it covered was nearly twice as much as the total area of red blood cells used to extract the phospholipids, as a result this ended up being a lucky find in bilayer structure and with more accurate measuring and due to the presence of proteins within the membrane the ratio of the two surfaces wouldn’t of been 2:1, although this original finding was not able to be duplicated as stimulated membrane research, it steered it in the right direction. In 1985 M. Diesenhofer, R.Huber and H. Michel show the structure of the membrane protein in high resolution, showing alpha helical transmembrane segments. In 1935 two men, Hugh Davson and James Danilli proposed a model of the cell membrane structure describing that it was made up of two layers a phospholipid bilayer and a protein layer, the phospholipid layers being sandwiched between the protein layers, the diagram below shows how they demonstrated this theory. James Danilli intended to further explain in the Davson and danilli model observations on the surface tensions in the lipid bilayers and even though there were some flaws ... ... middle of paper ... ...ous cytoplasm in the physical confirmation that was proposed. Same as if oil and water being left to stand, after being shaken will separate, meaning the hydrophilic and hydrophobic elements will sort themselves out into the correct order to isolate them from contact with the polar components. They supported their theories with both physical and biochemical evidence. During research they had successfully took apart the bilayers of frozen cell membranes from different areas to show the proteins embedded inside, other evidence had also shown to support that transmembrane proteins exist. Works Cited http://en.wikipedia.org/wiki/Davson–Danielli_model, Accessed, February, 11, 2014. http://www.whatislife.com/education/fact/history.htm, Accessed, February, 10, 2014 http://home.earthlink.net/~dayvdanls/CampOLs/MemModels.html, Accessed, February, 10, 2014.

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