Topic 2 - lipid bilayer (lec 3)

This is imporatnt in a membrane context bc saturated

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Unformatted text preview: aturated fatty acids are nice stright linear fatty acids as shown in this example here. Unsaturated fatty acids have a kink/bend every where they have a double bond, this becomes important in membrane properties. So these are hydrocarbon chains extending down one way to the third carbon of the glycerol backbone, is linked through a phosphate group a polar head group called the (rgroup), b/c there are four main polar head groups which are: Choline, ethanolamine, insitol and serine. The example here has choline as the rgroup, therefore this phosphoglyceride is called phosphoatidylcholine, b/c of the presence of the phosphate and these polar head groups, the head end of the molecule is polar and hydrophilic (water loving). The hydrocarbon chain of the fatty acids are non-polar and are hydrophobic (water fearing). This molecule has an hydrophobic and hydrophilic end, and this makes it an amphipathic molecule. in phosphoglyceride u see typically 16-18 carbons in the fatty acid chains and one fatty acid chain will be saturated and the other will be unsaturated. > Sphingolipids: They are built on a sphingosine backbone. Sphingosine has a long hydrocarbon chain as part of the molecule itself. Sphingolipids have only one fatty acid attached to them. The sphingosine backbone provides the other hydrocarbon chain. So structurally they are very similar to phosphoglycerides, but there is only one fatty acid chain. A particular important sphingolipid is sphingomyaline. In sphingomyaline the head group is phosphate and choline. > when u dump these amphipathic molecules into water the hydrocarbon chains tend to cluster together b/c of hydrophobic intercations trying to get away from water. They tend to be on the interior with the hydrophobic head groups facing towards the water. It is b/c of this that u get a lipid bilayer. 2) Glycolipids: Are very similar in structure to phospholipids, the main difference is that instead of a phosphate and r-group, they have sugars. They can have single sugar units or strings...
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