Lipids - Complete Summary 0.0 / 5 ? BiologyBiological moleculesBiological molecules, organic chemistry and biochemistryASAQA Created by: Betsy_2018Created on: 17-05-17 15:16 General Characteristics made of carbon, hydrogen and oxygen they have a very high carbon-hydrogen to oxygen ratio they have a low mass to high energy ratio they are insolube in water they are soluble in organic solvents they are osmotically inactive fatty acids (represented by RCOOH) 1 of 7 Functions source of energy insulation of heat and electrical impulses (myelin sheaths) waterproofing (oily secretion from skin) protection of organs 2 of 7 Triglycerides ester bond between each fatty acids and the glycerol molecule esterification (condensation reactions) result in ester bond formation emulsification (hydroylsis reactions) result in monoglyceride and fatty acid formation glycerol formula is C3H8O3 glycerol is an alcohol (OH group) fatty acids can be saturated (CnH2n+1)(COOH) monounsaturated (CnH2n-1)(COOH) polyunsaturated (CnH2n-1-1...) OH of COOH and H of OH (glycerol) form H20 non-polar 3 of 7 Phospholipids glycerol and 2 fatty acids insoluble - hydrophobic head phosphate group is soluble (polar) - hydrophilic head phosphate group is (PO4^3-) form bilayer for membrane or surfactants on water form glycolipids with carbohydrates in membrane 4 of 7 Test of Lipids 2cm3 of sample 5cm3 of ethanol shake to dissolve 5cm3 water cloudy-white colour = lipid presence emulsion formation 5 of 7 Digestion live produces bile salts break down lipids into micelle droplets by emulsification of ester bonds pancreas makes pancreatic juices pancreatic juice contains lipases breaks down ester bonds of micelle droplets into monoglycerise and fatty acids 6 of 7 Absorption micelle droplets remained associated with bile salts until they reach the villi of the ileum come into contact with villi micelles break down into monoglycerides and fatty acids with lipase enter the epithelial cells andreach endoplasmic reticulum reformed into triglycerides move to golgi body associate with cholesterol and lipoproteins to form chylomicrons leave epithelial cell by exocytosis enter lacteals break down into triglycerides in the blood vessels 7 of 7
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