Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Chapter 15 Lipids 1 15.3 Waxes, Fats, and Oils Waxes are esters of long-chain alcohols and fatty acids. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Waxes 2 Waxes are • esters of saturated fatty acids and long-chain alcohols • coatings that prevent loss of water by leaves of plants Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Fats and Oils: Triacylglycerols 3 Fats and oils are • also called triacylglycerols • esters of glycerol • produced by esterification • formed when the hydroxyl groups of glycerol react with the carboxyl groups of fatty acids Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Triacylglycerols 4 In a triacylglycerol, glycerol forms ester bonds with three fatty acids. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Formation of a Triacylglycerol 5 In a triacylglycerol, three hydroxyl groups on a glycerol molecule form ester bonds with the carboxyl groups of three fatty acids. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Triacylglycerols 6 Triacylglycerol may contain different fatty acids. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Learning Check 7 What are the fatty acids in the following triacylglycerol? O CH2 O C (CH2)16CH3 O CH CH2 O O C (CH2)7CH CH(CH2)7CH3 O C (CH2)12CH3 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Solution 8 What are the fatty acids in the following triacylglycerol? O CH2 O C Stearic acid (CH2)16CH3 O CH CH2 O O C (CH2)7CH CH(CH2)7CH3 O C (CH2)12CH3 Oleic acid Myristic acid Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Melting Points of Fats and Oils 9 A fat • is usually solid at room temperature • is prevalent in meats, whole milk, butter, and cheese An oil • is usually liquid at room temperature • is prevalent in plants such as olive and safflower Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Oils with Unsaturated Fatty Acids 10 Oils • have more unsaturated fats • have cis double bonds that cause “kinks” in the fatty acid chains • with “kinks” in the chains do not allow the triacylglycerol molecules to pack closely • have lower melting points than saturated fatty acids • are liquids at room temperature Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Diagram of Triacylglycerol with Unsaturated Fatty Acids 11 Unsaturated fatty acid chains with kinks cannot pack closely. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Percent Saturated and Unsaturated Fatty Acids in Fats and Oils 12 Vegetable oils have low melting points because they have a higher percentage of unsaturated fatty acids than do animal fats. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Learning Check 13 Draw the condensed structural formula of glyceryl trilinoleate (trilinolein). Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Solution 14 Draw the condensed structural formula of glyceryl trilinoleate (trilinolein). Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc.