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LIPIDS. Lipids (oils,fats,waxes). Fats are also known as TRIGLYCERIDES or LIPIDS Carbon, Hydrogen & Oxygen (have many hydrogens compared to oxygen) . Properties. (STORAGE) twice as much energy than carbohydrates insoluble in water Soluble in alcohol
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Lipids (oils,fats,waxes) • Fats are also known as TRIGLYCERIDES or LIPIDS • Carbon, Hydrogen & Oxygen (have many hydrogens compared to oxygen)
Properties • (STORAGE) twice as much energy than carbohydrates • insoluble in water • Soluble in alcohol • Can be solid (fat) or liquid at room temperature (liquid)
Functions of Fat • Store of energy • Insulation • Protecting Organs • Buoyancy • Found in cell membranes
Triglycerides FATTY ACID GLYCEROL GLYCEROL + 3 FATTY ACIDS TRIGLYCERIDE + 3 WATER
Formation of lipid molecule The three fatty acids are joined to glycerol by condensation reactions
Fatty acids (FA’s) • R-COOH COOH = carboxylic acid R = hydrocarbon chain • Saturated Fatty Acids • Unsaturated Fatty acids
Hydrolysis of lipids Lipids can be hydrolysed into fatty acids and glycerol by: • heating with acid or alkali. • using the enzyme lipase at an optimum temperature and pH.
Emulsion test for lipids This involves: • The sample is placed into a test tube with 2cm3 of ethanol; • shake the mixture so that the fat dissolves; • add this to water in another test tube and mix the contents; • a white or cloudy emulsion of fat droplets indicates lipid is present.
Phospholipids GLYCEROL + 2 FA’s + Phosphate Phospholipid + 3 Water
Recap questions. • 1. Name two functions of lipids. • 2. What does a triglyceride consist of? • 3. Draw glycerol. • 4. What does the R group on the fatty acid represent? • 5. What is the difference between a saturated and an unsaturated fatty acid?
Recap questions. • 6. What components make up a phospholipid? • 7. What term is used to describe the phosphate head and its “relationship” with water? • 8. Where are phospholipids mainly found? • 9. How do we test for the presence of lipids?