AP Biology Lipids Lipids are composed of C, H, O Not considered polymers-no subunits “Family groups” Fats Phospholipids Steroids Polymers big molecules made of smaller subunits not a continuing chain
AP Biology Fats Structure: Glycerol and fatty acids fatty acid = long HC “tail” with carboxyl (COOH) group “head” dehydration synthesis H2OH2O enzyme
AP Biology Building Fats Triacylglycerol 3 fatty acids linked to glycerol Ester linkage = between OH & COOH hydroxylcarboxyl
AP Biology Dehydration synthesis H2OH2OH2OH2OH2OH2OH2OH2O enzyme dehydration synthesis
AP Biology Fats store energy Long HC chain polar or non-polar? hydrophilic or hydrophobic? Function: Store Energy concentrated all H-C! 2x carbohydrates Cushioning Insulates think whale blubber!
AP Biology Saturated fats All C bonded to H No C=C double bonds Solid at Room Temp. Butter Lard contributes to cardiovascular disease (atherosclerosis) = plaque deposits
AP Biology Unsaturated fats C=C double bonds in the fatty acids One or more double bonds Plant Fats Liquid at Room Temp. the kinks made by double bonded C prevent the molecules from packing tightly together
AP Biology Saturated vs. unsaturated _______________
AP Biology Phospholipids Structure: glycerol + 2 fatty acids + PO 4 PO 4 negatively charged
AP Biology Phospholipids Hydrophobic or hydrophilic? fatty acid tails = Hydrophobic PO 4 head = Hydrophilic split “personality” interaction with H 2 O is complex & very important! “repelled by water” “attracted to water”
AP Biology Phospholipids in water Tails repelled by water Heads attracted to water can self-assemble into “bubbles” bubble = “micelle” can also form a Bilayer early evolutionary stage of cell? bilayer water
AP Biology Why is this important? Phospholipids create a barrier in water define outside vs. inside they make Cell Membrane
AP Biology Steroids Structure: 4 fused C rings + ?? different steroids created by attaching different functional groups to rings different structure creates different function What are some examples: cholesterol
AP Biology Cholesterol Important cell component Part of the cell membrane Used to make other types of steroids including vertebrate sex hormones high levels in blood may contribute to cardiovascular disease
AP Biology Cholesterol helps keep cell membranes fluid & flexible Important component of cell membrane
AP Biology From Cholesterol Sex Hormones What a big difference a few atoms can make!