Lipids

1. Fats Lipids Oils

2. Lipids: Fats & Oils

3. 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. enzyme H2O Fats • Structure: • Glycerol and fatty acids • fatty acid = long HC “tail” with carboxyl (COOH) group “head” dehydration synthesis

5. Building Fats • Triacylglycerol • 3 fatty acids linked to glycerol • Ester linkage = between OH & COOH hydroxyl carboxyl

6. enzyme enzyme enzyme H2O H2O H2O H2O Dehydration synthesis dehydration synthesis

7. 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. 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. 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 doublebonded C prevent the molecules from packing tightly together

10. Saturated vs. unsaturated _______________ _______________

11. Phospholipids • Structure: • glycerol + 2 fatty acids + PO4 • PO4 negatively charged

12. Phospholipids • Hydrophobic or hydrophilic? • fatty acid tails = Hydrophobic • PO4 head = Hydrophilic • split “personality” “attracted to water” interaction with H2O is complex & very important! “repelled by water”

13. 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? water bilayer water

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

15. Steroids • Structure: • 4 fused C rings + ?? • different steroids created by attachingdifferentfunctional groups to rings • different structure creates different function • What are some examples: cholesterol

16. 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. Cholesterol helps keep cell membranes fluid & flexible Important component of cell membrane

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

19. Let’s build some Lipids!