1. AP Biology 2006-2007 Lipids Oils Fats

2. AP Biology Lipids: Fats & Oils

3. 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

4. AP Biology Fats  Structure:  Glycerol and fatty acids  fatty acid = long HC “tail” with carboxyl (COOH) group “head” dehydration synthesis H2OH2O enzyme

5. AP Biology Building Fats  Triacylglycerol  3 fatty acids linked to glycerol  Ester linkage = between OH & COOH hydroxylcarboxyl

6. AP Biology Dehydration synthesis H2OH2OH2OH2OH2OH2OH2OH2O enzyme dehydration synthesis

7. 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!

8. 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

9. 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

10. AP Biology Saturated vs. unsaturated _______________

11. AP Biology Phospholipids  Structure:  glycerol + 2 fatty acids + PO 4  PO 4 negatively charged

12. 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”

13. 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

14. AP Biology Why is this important?  Phospholipids create a barrier in water  define outside vs. inside  they make Cell Membrane

15. 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

16. 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

17. AP Biology Cholesterol helps keep cell membranes fluid & flexible Important component of cell membrane

18. AP Biology From Cholesterol  Sex Hormones  What a big difference a few atoms can make!

19. AP Biology 2006-2007 Let’s build some Lipids!