Topic 2 - lipid bilayer (lec 3)

In this figure the human line got red colour and the

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Unformatted text preview: s figure the human line got red colour and the mouse were green. Than they fused the two cells together. > If the membrane is not fluid we would expect that the fused cell would be half red and half green. but what they actually found that in a relatively short time, the signals were mixed all over the fused cell. >So the mouse proteins migrated into the human half and the human proteins migrated into the mouse half of the cell, within the membrane. Its a process called lateral diffusion. When things can move around within the membrane. For this to occur, clearly the membrane has to be fluid, for the proteins to be able to move around in the membrane. Its not static, it is very loose and things can be move around easily. Intensity of Fluorescence Membrane structure Fluid mosaic model Lipid-protein assembly in which components are held together in a thin sheet by non-covalent bonds Two fluid lipid layers – structural backbone, permeability barrier Mosaic of proteins – unique complement responsible for specific functions ~10 nm thick Fluorescence Recovery After Photobleaching BIO 1140 – SLIDE 7 Fig. 5.4 R group Phosphate glycerol Fatty acids Phospholipids (amphipathic) Phosphoglycerides Glycerol backbone Hydrophilic head group: phosphate + serine, choline, ethanolamine, inositol 2 fatty acids (16-18 C); saturated & unsaturated Sphingolipids, e.g. Sphingomyelin Sphingosine backbone Hydrophilic head group: phosphate + choline 1 fatty acid Absent from plants, bacteria Phosphatidylcholine glycerol sphingosine fatty acid phosphate fatty acid non-polar choline phosphate fatty acid choline polar BIO 1140 – SLIDE 8 The lipid bilayer Gorter and Grendel, 1925 Key component of permeability barrier Composition Fig. 5.5 Phospholipids (amphipathic) Phosphoglycerides Glycerol backbone Hydrophilic head group: phosphate + serine, choline, ethanolamine, inositol 2 fatty acids (16-18 C); saturated & unsaturated Sphingolipids, e.g. Sphingomyelin Sphingosine backbon...
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