Lipids v Lipids are a heterogeneous group of

Lipids v Lipids are a heterogeneous group of compounds. v insoluble in water and soluble in organic solvent such as (alcohol, acetone).

Classification of lipid Simple lipid Compound lipid Derived lipid

§ fats are lipids that solid at room temperature. § oils are lipids that liquid at room temperature. e n a br em P m l l e c f o t ar So n o i t c n Fu d i p i l f o Regulate activities of cells and tissues ur ce of en e rg y

Iodine test v. Specific test for (unsaturated fatty acid). v. Depends on reaction of iodine reagent with double bond of fatty acid. v. Produced colorless (+). + -

Reaction test v. Specific test for fatty acid (saturated and unsaturated). v. Depends on fatty acid decolorizes the red color of phenolphthalein reagent because it have free carboxyl group. v. Produced colorless (+).

Copper acetate test v. Specific test for distinguish between TG, unsaturated and saturated fatty acid. v. Depends on reaction of (Cu+2 ) with (COOH) of fatty acid. Neutral unsaturated

Emulsification of oils v Emulsion when lipid shake with water then broken down to give minute particles which is immiscible with water. v Because oil particles will get together and carried above the surface of water. v. So add soap to this mixture, oil will be in this solution (oil + water + soap) emulsion permanent. miscible to give

ü Chemical substances that make emulsion permanent are: (soap, proteins, bile salts and phospholipid).

Lipid tests 1 - iodine Test : (test for unsaturated fatty acid) (1 ml) of lipid (2 drops) OF reagent 2 - reaction Test : (test for general fatty acid) (1 ml) of liquid (2 drops) of reagent 3 - copper acetate Test : (distinguish between lipids) (1 ml) of liquid (1 ml) OF reagent, shake, let stand oleic (+) Brown (-) Purple (palmitic) 4 - emulsification of oils: (1 ml) of liquid (2 ml) of water Few drop of soap and shake (-) TG (+) palmitic TG Saturated 5 - cholesterol test: Salkowski test (2 ml) of cholesterol in dry test tube (2 ml) of H 2 SO 4 (con. ) Mix, let stand unsaturated

Reaction Test : (1 ml ) of unknown (2 drop) of reagent Iodine Test : (1 ml) of unknown (2 drop) of reagent Reaction test Copper acetate test (-) neutral (+) Fatty acid Iodine test Copper acetate Test : (1 ml) of unknown (1 ml) of reagent, shake, let stand (+) (-)