2. Regents Biology 2003-2004 Lipids  Hydrophobic molecules  Do NOT consist of polymers  Function:  energy storage  cell membrane  protection - cushions organs  insulates body

3. Regents Biology Structure of Fat

4. Regents Biology What are lipids composed of? 1 glycerol + 3 fatty acids  lipids (triglycerides)  Vary in length and number and location of double bonds

5. Regents Biology How are lipids made and broken down?

6. Regents Biology How are lipids made? Broken down?

7. Regents Biology Saturated Fats  Mostly animal fats  solid at room temperature  Saturated with hydrogen  All single bonds  Can be tightly packed  Limit the amount in your diet

8. Regents Biology Unsaturated fats  Plant, vegetable & fish fats (oils)  liquid at room temperature  the fat molecules don’t stack tightly together  Double bond causes a kink  Better choice in your diet

9. Regents Biology 2003-2004 Saturated vs. Unsaturated Examples saturatedunsaturated  Meat  Butter  Ice Cream  Cookies  Animal Fat  Olive oil  Canola Oil  Avocado  Nuts  Seafood  Soy

10. Regents Biology 2003-2004 Other lipids in biology  Cell membranes are made out of phospholipids  2 fatty acid tails & a phosphate group  heads are on the outside touching water  “like” water (hydrophilic)  tails are on inside away from water  “scared” of water (hydrophobic)  forms a barrier between the cell & the outside

11. Regents Biology 10  Phospholipid structure CH 2 O P O O O CH CH 2 OO C O C O Phosphate Glycerol (a) Structural formula (b) Space-filling model Fatty acids (c) Phospholipid symbol Hydrophobic tails Hydrophilic head Hydrophobic tails – Hydrophilic head CH 2 Choline + Figure 5.13 N(CH 3 ) 3

12. Regents Biology  The structure of phospholipids  Results in a bilayer arrangement found in cell membranes Hydrophilic head WATER Hydrophobic tail Figure 5.14

13. Regents Biology Other lipids in biology  Steroids, Ex: Cholesterol  Carbon skeleton of 4 fused rings  good molecule in cell membranes  make hormones from it  including sex hormones  but too much cholesterol in blood may lead to heart disease HO CH 3 H3CH3C

14. Regents Biology Other lipids in biology  Waxes  Bees, ears, shiny leaves, shiny feathers, hair  Repels water  For protection