AP Biology Lipids Oils Fats

AP Biology Lipids: Fats & Oils

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 H2OH2OH2OH2OH2OH2O 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  Vegetable oil  Plant and Fish 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 How Detergents Work  Detergents:  amphipilic compounds with polar and hydrophobic groups  many different detergents composed of different types of polar and hydrophobic groups  forms mixed micelles with lipids  bind to hydrophobic portions of proteins Detergnet: Sodium dodecyl sulfate

AP Biology Cleansing action of soap

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!

AP Biology Bile Acids  Synthesized in the liver, stored in the gallbladder, and secreted into the intestine where their function is emulsify dietary fats and aid in their absorption and digestion.

AP Biology Let’s build some Lipids!