Presentation on theme: "long term energy storage"— Presentation transcript:
1 long term energy storage Lipidslong term energy storageconcentrated energyAdapted from Kim Fogia and David Knuffke work
2 Lipids Lipids are composed of C, H, O “Family groups” long hydrocarbon chains (H-C)“Family groups”fatsphospholipidssteroidsDo not form polymersbig molecules made of smaller subunitsnot a continuing chainMade of same elements as carbohydrates but very different structure/ proportions & therefore very different biological properties
3 dehydration synthesis FatsStructure:glycerol (3C alcohol) + fatty acidfatty acid = long HC “tail” with carboxyl (COOH) group “head”enzymeLook at structure… What makes them hydrophobic?Note functional group = carboxylH2Odehydration synthesis
4 Building Fats Triacylglycerol (triglycerides) 3 fatty acids linked to glycerolester linkage = between OH & COOHhydroxylcarboxylBIG FAT molecule!!
5 Dehydration synthesis H2Odehydration synthesisenzymeH2OPulling the water out to free up the bondenzymeH2OenzymeH2O
6 Fats store energy Long HC chain Function: polar or non-polar? hydrophilic or hydrophobic?Function:energy storageconcentratedall H-C!cushion organsinsulates bodythink whale blubber!What happens when you add oil to waterWhy is there a lot of energy stored in fats?• big molecule• lots of bonds of stored energySo why are we attracted to eating fat?Think about our ancestors on the Serengeti Plain & during the Ice Age. Was eating fat an advantage?
7 Saturated fats All C bonded to H No C=C double bonds long, straight chainmost animal fatssolid at room temp.contributes to cardiovascular disease (atherosclerosis) = plaque depositsMostly animal fats
8 Unsaturated fats C=C double bonds in the fatty acids plant & fish fats vegetable oilsliquid at room temperaturethe kinks made by double bonded C prevent the molecules from packing tightly togetherMostly plant lipidsThink about “natural” peanut butter:Lots of unsaturated fats Oil separates outCompanies want to make their product easier to use:Stop the oil from separating Keep oil solid at room temp.Hydrogenate it = chemically alter to saturate itAffect nutrition?
11 Phospholipids Hydrophobic or hydrophilic? fatty acid tails = PO4 head =split “personality”Amphipathic: containboth hydrophilic andhydrophobic elementshydrophobichydrophillic“attracted to water”“repelled by water”
12 Phospholipids in water Hydrophilic heads “attracted” to H2OHydrophobic tails “hide” from H2Ocan self-assemble into “bubbles”can also form a phospholipid bilayerMicelles- hydrophilic heads of phospholipids face H2O and tails are forced togetherwaterLipid micellebilayerwater
13 Why is this important? Phospholipids create a barrier in water define outside vs. insidethey make cell membranes!
14 Steroids Structure: 4 fused C rings + ?? different steroids created by attaching different functional groups to ringsdifferent structure creates different functionexamples: cholesterol, sex hormonescholesterol
15 Cholesterol Important cell component animal cell membranes precursor of all other steroidsincluding vertebrate sex hormoneshigh levels in blood may contribute to cardiovascular disease
16 Cholesterol Important component of cell membrane helps keep cell membranes fluid & flexible
17 From Cholesterol Sex Hormones What a big difference a few atoms can make!Same C skeleton, different functional groups
19 Lipid molecule hydrolysis produces Glycerol and fatty acidsGlycerol and waterWater and amino acidsGlucose and fatty acidsWater and fatty acids
20 In phospholipids, at least one fatty acid chain is “kinked”, resulting in a bent structure. This phenomenon, which gives fluidity to cell membranes, is caused byExcess hydrogen atoms around the bondHydrophobic interactionsMultiple double bondsSulfhydryl group interactionsMultiple ionic bonds
21 The single structural unit common to all lipids is FatGlycogenCholesterolGlycerolCarbon