VIDEO LECTURE 1 LIPIDS CLASSIFICATION& FUNCTIONS

1. VIDEO LECTURE 1LIPIDSCLASSIFICATION& FUNCTIONS

2. DEFINITION Agroup of organic compounds that are insoluble in water(hydrophobic) but soluble in organic solvents Most membrane lipids are amphipathic small molecules having polar head group and non polar tail group

3. FUNCTIONS OF LIPIDS • MEMBRANE STRUCTURE • FUELS AND STORAGE FROMS OF ENERGY • DIGESTION(BILE) AND ABSORPTION OF FAT SOLUBLE VITAMINS • STEROID HORMONES • THEY PROVIDE INSULATION FROM ENVIRONMENT

4. Fatty Acids A fatty acid is a carboxylic acid with a long aliphaticchain which can be eithersaturated or unsaturated Fatty acids that have carbon–carbon double bonds are known as unsaturated. Fatty acids without double bonds are known as saturated

5. Naming of fatty acids According to IUPACnames/delta-xnomenclature counting begins from the carboxylic acid end. Double bonds are labelled with cis-/trans And each double bond is indicated by Δx, where the double bond is located on the x thcarbon–carbon bond

6. Examples of saturated fatty acids

7. Examples of unsaturated fatty acids

8. Cis and Trans fatty acids • Cis-fatty acids are isomers in which the continuing carbon chains on each end of the double bond face the same direction. A cis-isomer is bent or “kinked,” preventing cis-fatty acids from packing closely together. • Trans-fatty acids are isomers often created during commercial food production. In trans-fatty acids, the continuing carbon chains face opposite directions around a double bond. Trans-isomers are structurally similar to saturated fatty acids 

9. LIPIDS CLASSIFICATION

10. Natural Fats/Tri acyl Glycerides • Triglycerides are chemically tri esters of fatty acids and glycerol. •  Triglycerides are the main constituents of body fatin animals, as well as vegetable fat.

11. Simple and mixed tri acyl glycerides

12. waxes

13. Examples of waxes

14. Complex/Compound Lipids • Esters of fatty acids with alcohol, containing non-lipid Group (PO4, Nitrogenous base, or sugar) • Compound Lipids are Further Classified as: • PHOSPHO-LIPIDS • GLYCO-LIPIDS • PROTEO-LIPIDS (LIPO-PROTEINS) • SULPHO-LIPIDS

15. Types of phospholipids • The simplest glycerophospholipid is phosphatidic acid (PA) • It consists of glycerol, phosphate, and 2 fatty acyl chains in ester linkages

16. Different types of phospholipids Phosphatidylethanolamine (cephalin) (PE) • Phosphoinositides: Phosphatidylinositol ((PI)  • Phosphatidylcholine (lecithin) (PC) • Phosphatidylserine (PS)

17. Functions of phospholipids • major constituents of all cell membranes • components of bile • anchor some proteins in membranes • signal mediators • components of lung surfactant • components of lipoproteins

18. Plasmalogens • Plasmalogens have an ether-linked hydrocarbon chain at C-1 of glycerol, instead of ester-linked fatty acid Platelet-activating factor (PAF) is a plasmalogen (a phosphatidalcholine) with an acetyl group at C-2 of glycerol It has potent physiologic actions (platelet activation; inflammatory responses; bronchoconstriction