2. Lipids Triglycerides Phospholipids Sterols

3. Lipids Lipids are a class of nutrients that includes: –Triglycerides (fats and oils) –Phospholipids –Sterols –Waxes Composed of carbon, hydrogen, and oxygen. Lipids are hydrophobic (insoluble in water)

4. Characteristics of Lipids Composed of Carbon, Hydrogen, and Oxygen Greater than 2:1 ratio of H:O Includes fats, oils, phospholipids, and cholesterol Building blocks are fatty acids and glycerol. Energy storage molecules Phospholipids part of cell membrane

5. Fatty Acid Structure Carboxyl group (COOH) forms the acid. “R” group is a hydrocarbon chain.

6. A Representative Fatty Acid

7. Fatty Acids Fatty acids vary in carbon chain lengths, degree of unsaturation, and number of double bonds. –Degree of Saturation- Saturation affects the physical characteristics of the fat and its storage properties

8. Saturated vs. Unsaturated Saturated - Saturated fatty acids carry the maximum possible number of hydrogen atoms.. Stearic acid, an 18-carbon saturated fatty acid

9. Saturated vs. Unsaturated Unsaturated – Unsaturated fatty acids have at least one double bond. There are 2 types –Monounsaturated fatty acid (MUFA) Oleic acid, an 18-carbon monounsaturated fatty acid

10. Saturated vs. Unsaturated Polyunsaturated fatty acids (PUFA) –have at least two double bonds. Linoleic acid, an 18-carbon polyunsaturated fatty acid

11. Saturated and Unsaturated Fatty Acids Help Shape Foods

12. Saturated Fatty Acid Unsaturated Fatty Acid

13. Glycerol An alcohol composed of a three carbon chain.

14. Synthesis of a Fat

15. Triglycerides TG (fats and oils) – composed of 3 fatty acids attached to a glycerol

16. TG

17. Phospholipids contain glycerol, 2 fatty acids and a phosphate group. Soluble in both water and fat Roles of phospholipids –Transport lipids through Plasma membrane –Make up the cell membrane

18. Phospholipids

19. Sterols –cholesterol, vit D, testorone –Multiple carbon-ring structure. –Found in plant and animal foods –Cholesterol is found in animal foods only - meat, eggs, fish, poultry and dairy products

20. Sterols Roles of sterols –Needed to make bile acids, sex hormones, adrenal hormones and vitamin D –Component of cell membranes –Cholesterol forms deposits in the artery wall causing artherosclerosis.

21. Sterols