MCB 450 1st EditionLecture 8Outline of Last Lecture I. MonosaccharidesII. Glycosidic bondsIII. PolysaccharidesOutline of Current Lecture I. Fatty acids: structure, nomenclature, propertiesII. Lipids: components, structure, propertiesIII. Functions of lipids:a. energy storageb. components of cell membranesIV. Membrane lipidsa. phospholipids: phosphoglycerides& sphingolipidsb. cholesterolV. Lipid bilayersa. why they formb. bilayer fluidityc. lipid mobility and asymmetryCurrent LectureFive classes of lipids-Fatty acids can have saturated or unsaturated hydrocarbon chains-Phospholipids -- have esterified head groups-Sterols -- polycyclic moleculesMajor membrane components: fatty acids (FA)-C-atom most distant is the omega-carbonUnsaturated fatty acids-Unsaturation means we introduce a double bond-18:1 -- has one double bond-18:2 -- has two double bondsFatty acid nomenclature-DO NOT include carbonyl bond when counting double bonds in fatty acids-Alkene (..decen…) -- carbon - carbon double bound-Alkane ( ..decan…) -This nomenclature gives some indication to the physical properties of the fatty acidCis-polyunsaturated fats are essential components of our diet-Linolenate -- is the most extreme structure that we will be expected to recognizeThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Classes of fatty acid-containing lipids-Overview slideoClassify lipids based on their function in the celloPink blocks show the "backbone" to which the fatty acids are attachedTriacylglycerols-Can have different fatty acid chains attached to the same glycerol backbone-Neutral and not a great deal of polaritySaponification-Linkages can easily be broken-Saponification -- making soapoTreat the triacylglycerol with hydroxyl and it will create detergentsMost natural plant and animal fats triacylglycerols-Different types of organisms make different triacylglycerolsTriacylglycerols are a major energy reserve-Are much better at being a major energy reserve than glycogen and glucose stores...allow to survive longeroBecause they are much more reduced than carbohydratesoTriacylglycerols can be stored more efficientlyCarbon-containing fuel molecules-Octane -- gasolineSphingolipids-Sphingosine -- mimics the "backbone" aka glycerol in a triacylglycerol-No ester linkage-And longer fatty acid chain does not contain ester linkages-So does not break apart when you treat with hydroxyl-Originally discovered when they were separated from neural tissue-Name of X -- is the name of the head groupoAttachment of different head groups creates different sphingolipidsCholesterol derivatives-Cholesterol makes up five families of steroid hormones-Hence cholesterol is a very important membrane componentAnalysis of lipids-1: extraction-Try to solubilize the lipidsoWill spin out all of the insoluble parts to allow lipids to remainAnalysis of lipids-2: separation-Then typically the next step is to do some sort of chromatographyDetergents are emulsifying agents-Example of a detergent molecule emulsifying a drop of greaseLipids self-assemble into membranes in an aqueous environment-Tail to tail arrangement of two lipid layers, they will self-assemble into this formation-When this formation happens MANY water molecules are freed upSelf-association of lipids into bilayers-Formation is favored even though you are introducing a lot of order to these moleculesBilayer fluidity-Go from gel phase to more solid phase to more fluid state-If it is below the transition temperature it will undergo the phase changeDemonstration of lateral diffusion of lipids-Attach fluorescent group to be able to detect where head group are-Can conclude that the phospholipids in this bilayer have fused and movedComposition of organellar membranes varies-Shows that different cellular membranes have different make