Chem 150 Unit 5 - Biological Molecules I LipidsIntroductionSlide 3Fatty AcidsSlide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Biochemical Compounds & Their Interactions with Water (Unit 3)Slide 15WaxesAlcohols, Carboxylic Acids & Esters (Unit 2)Slide 18Slide 19Slide 20QuestionsReactions Involving Water (Unit 4)TriglyceridesSlide 24Slide 25Slide 26PowerPoint PresentationSlide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Oxidation and Reduction (Unit 4)Slide 36Slide 37Slide 38Slide 39Slide 40Slide 41Slide 42Slide 43Slide 44Slide 45Slide 46Slide 47Reactions With Water (Unit 4)Slide 49Phospholipids and GlycolipidsSlide 51Slide 52Slide 53Slide 54Slide 55Slide 56Slide 57Slide 58Slide 59Slide 60SteroidsSlide 62Slide 63Slide 64LipoproteinsSlide 66Slide 67EicosanoidsMembranesSlide 70The EndChem 150Chem 150Unit 5 - Biological Molecules IUnit 5 - Biological Molecules ILipidsLipidsLike organic molecules, biological molecules are Like organic molecules, biological molecules are grouped into families. There are four major families grouped into families. There are four major families of biological molecules, including of biological molecules, including proteinsproteins, , nucleic nucleic acidsacids, , carbohydratescarbohydrates, and , and lipidslipids. The lipids are . The lipids are the subject of this unit. Of these four families, the the subject of this unit. Of these four families, the lipids are the structurally the most diverse. This is lipids are the structurally the most diverse. This is because unlike members of the other three families, because unlike members of the other three families, members of this families do no share a common members of this families do no share a common structural feature, but rather share a common structural feature, but rather share a common physical property; the are hydrophobic.physical property; the are hydrophobic.22IntroductionIntroductionLipids are hydrophobic, nonpolar molelcules.Lipids are hydrophobic, nonpolar molelcules.•They are soluble in nonpolar solvent.They are soluble in nonpolar solvent.•They are insoluble in polar solvents, such as waterThey are insoluble in polar solvents, such as waterThey are isolated from the other biological molecules by They are isolated from the other biological molecules by extracting them with nonpolar solvents.extracting them with nonpolar solvents.33IntroductionIntroductionThe types of lipids that we will look at include.The types of lipids that we will look at include.•Fatty AcidsFatty Acids•In the carboxylic acid familyIn the carboxylic acid family•WaxesWaxes•Fatty Acids + AlcoholsFatty Acids + Alcohols•TriglyceridesTriglycerides•3 Fatty acids + glycerol3 Fatty acids + glycerol•Phospholipids and glycolipidsPhospholipids and glycolipids•2 fatty acids + glycerol + phosphate + X2 fatty acids + glycerol + phosphate + X•SteroidsSteroids•Derivatives of cholesterolDerivatives of cholesterol•EicosanoidsEicosanoids•Derivatives of the Fatty acid arachidonic acidDerivatives of the Fatty acid arachidonic acid•MembranesMembranes•Formed from phospholipids and glycolipidsFormed from phospholipids and glycolipids44Fatty AcidsFatty AcidsFatty acids contain a carboxylic acid groupFatty acids contain a carboxylic acid group•This should make them quite polarThis should make them quite polarHowever, they also contain a long hydrocarbon tailHowever, they also contain a long hydrocarbon tail•Which overall, makes them nonpolar.Which overall, makes them nonpolar.nonpolarnonpolarnonpolarnonpolarpolarpolarpolarpolar55Fatty AcidsFatty AcidsFatty acids typically contain between 12 and 20 carbonsFatty acids typically contain between 12 and 20 carbons•The number is usually always even.The number is usually always even.•The nonpolar tails interact with London forces.The nonpolar tails interact with London forces.nonpolarnonpolarnonpolarnonpolarpolarpolarpolarpolar66Fatty AcidsFatty AcidsMelting points for saturated fatty acids:Melting points for saturated fatty acids:No. of CarbonsNo. of CarbonsNo. of CarbonsNo. of CarbonsMelting Temperature Melting Temperature {°C}{°C}Melting Temperature Melting Temperature {°C}{°C}77Fatty AcidsFatty AcidsSome fatty acids contain double bondsSome fatty acids contain double bonds•unsaturatedunsaturated•monounsaturatedmonounsaturated•polyunsaturatedpolyunsaturated•polyunsaturatedpolyunsaturated88Fatty AcidsFatty AcidsThe common fatty acids found in biological systems are The common fatty acids found in biological systems are shown in Table 8.1 of Raymond.shown in Table 8.1 of Raymond.TextTextTextTextLinolenic acid is one of the Linolenic acid is one of the omega-3 fatty acidsomega-3 fatty acids..Linolenic acid is one of the Linolenic acid is one of the omega-3 fatty acidsomega-3 fatty acids..99Fatty AcidsFatty AcidsNormally the double bonds are Normally the double bonds are ciscis•This lowers the melting points for fatty acids containing This lowers the melting points for fatty acids containing double bonds.double bonds.No. of Double BondsNo. of Double BondsNo. of Double BondsNo. of Double BondsMelting Temperature Melting Temperature {°C}{°C}Melting Temperature Melting Temperature {°C}{°C}1010Fatty AcidsFatty AcidsThe The ciscis double bonds produce kinks, which disrupt the double bonds produce kinks, which disrupt the London forces by preventing the tails from packing close to London forces by preventing the tails from packing close to one another.one another.1111Fatty AcidsFatty AcidsAs acids, the carboxylic acid group in fatty acids can react As acids, the carboxylic acid group in fatty acids can react with a base to produce a carboxylate ionwith a base to produce a carboxylate ion•By donating its proton (HBy donating its proton (H++) to the base the fatty acid ) to the base the fatty acid becomes negatively charged.becomes negatively charged.•We will talk more about acids and bases in Unit 6We will talk more about acids and bases in Unit 61212Fatty AcidsFatty AcidsThe negative charge makes the polar head portion of the the The negative charge makes the polar head portion of the the fatty acid even more more polar and hydrophilic.fatty acid even more more polar and hydrophilic.1313Fatty AcidsFatty AcidsThe salts of fatty acids are also called The salts of fatty acids are also called soapssoaps, and are , and are considered considered amphipathicamphipathic, , meaning they have a part that is meaning they have a part that