LIPIDS -organic macromolecules that are insoluble in water -contain many Hydrogen atoms -contain more energy than carbohydrates -there are 5 groups of lipids that are important to living things: Oils, Fats, Phospholipids, Waxes and Steroids

Function 1. Long term nutrient and energy storage 2. Cushions vital organs in mammals 3. Insulation against heat loss 4. Hormones to send messages around the body 5. Primary structure of cell membranes   -1 gram of lipid contains 9 calories, whereas 1g of CHO contains 4 calories. Thus, 1 gram of lipid contains 2.25times as much energy as 1 gram of CHO.

OILS and FATS -made up of subunits called triglycerides -triglycerides are made up of a glycerol molecule and three fatty acids Oils and Fats Triglycerides Glycerol 3 Fatty Acids Glycerol Molecule: Fatty Acids: -3 Carbon Chain -long chains of C and H atoms -OH (Hydroxyl group) attached to -carboxyl group at one end each carbon      

Triglyceride:   The combination of a glycerol molecule plus three fatty acids is called a TRIGLYCERIDE

-the carboxyl group of each fatty acid is linked to the glycerol molecule on one of three reaction sites, it is a dehydration synthesis reaction

-it is the different types of fatty acids that allow for wide variation in fat molecules -fatty acids may be identical or non-identical, short or long, saturated or unsaturated -the fewer the hydrogen atoms, the more double bonds between carbons there will be. The number of double bonds between C atoms determines if a fatty acid is Saturated or Unsaturated.

  Saturated Fatty Acid -each of the C atoms beyond the carboxyl group has NO double bonds, single bonds only between the C atoms -they contain the maximum number of hydrogen atoms (saturated with H) -usually solid at room temperature, and usually come from animal products (ie) butter -b/c there are only single bonds between C atoms, the saturated fatty acid is straight Saturated Triglyceride -a triglyceride that contains saturated fatty acids

UnSaturated Fatty Acid -one or more double bonds between carbons in the fatty acid tail -tail ‘kinks’ at C=C so the molecules do not pack closely enough to be solid at room temperature -liquid at room temperature , usually are plant fats and referred to as oils (corn oil, olive oil...)   Unsaturated Triglyceride -triglycerides that contain fatty acids with at least one double bond between carbon atoms Polyunsaturated Triglyceride -triglycerides that have many double bonded carbons -liquid at room temperature

Polyunsaturated Triglycerides Characteristics: -have low melting points -liquid oils at room temperature Examples: -sunflower, canola, olive oil (all made from plants), margarine Margarine= -hydrogen gas PLUS polyunsatured triglycerides found in oils -oil changes from a liquid to a solid and companies add yellow food colouring Butter, Lard -produced by animals -saturated triglycerides have been shown to lead to heart attack and strokes Why? The saturated triglycerides can clog arteries.

B) Phospholipids Structure:-consist of a glycerol molecule and TWO fatty acids Function:-make up the structure of the cell membrane, protects cell from external environment   Wax Function-waterproof, provide protective coatings, earwax prevents microorganisms from entering the middle ear D) Steroids Structure- composed of four fused carbon rings with various functional groups attached to them Function- makes many human hormones (ie) testosterone in males; cholesterol is needed for nerve cells and other cells to function properly -high concentration of cholesterol is known to lead to clogged