Presentation on theme: "Goals for the day… Review practice Exam 3"— Presentation transcript:
1 Goals for the day… Review practice Exam 3 Review naming and physical properties of carboxylic acids and esters.Review physical properties of carboxylic acids and esters.Review reactions of carboxylic acids and esters.Review lipids (both fatty acid lipids and steroids).Review physical properties of lipids.Review reactions of lipids.
37 Learning CheckAssign the melting point (mp) of −17°C, 13°C, or 69°C to each one of the following 18-carbon fatty acids, and list the fatty acids in order from highest to lowest melting point. Explain.A. oleic acidB. stearic acidC. linoleic acid
38 SolutionStearic acid is saturated and would have a higher melting point than the unsaturated fatty acids. Oleic acid, which has one double bond, has a higher mp than linoleic acid, which has two double bonds.B. stearic acid mp 69°C saturatedA. oleic acid mp 13°C unsaturated with one double bondC. linoleic acid mp −17°C unsaturated with twodouble bonds
39 Which of these are: saturated, monounsaturated omega-3 and monounsaturated omega-6? CH3—CH2—CH2—CH2—CH2—CH2—CH2—CH2—CH2—COOHB.C.
40 Solution A. saturated (no double bonds) CH3—CH2—CH2—CH2—CH2—CH2—CH2—CH2—CH2—COOHB. monounsaturated omega-3 (double bond at 3)C. monounsaturated omega-6 (double bond at 6)
41 Recognize the difference… Oil: at room temperature, it is a viscous liquid. Triacylglyceride that has unsaturation, so has a low melting point.Fat: at room temperature, it is a solid. Triacylclyceride that is saturated, so has a higher melting point.Wax: Contains an ester of a “fat” and an alcohol.
42 Glycerophospholipids Contain Amino Alcohols. Three amino alcohols found in glycerophospholipids are choline, serine, and ethanolamine.In the body, at a physiological pH of 7.4, these amino alcohols are ionized.Insert structures of amino alcohols pg 618 bottom
43 Four ReactionsThe chemical reactions of triacylglycerols are similar to those of alkenes and esters.esterification (making the triacylglycerol)ester hydrolysis (breaking the triacylglycerol into the fatty acid and glycerol)Saponification (adding NaOH and making a salt)hydrogenation (adding H2 to the double bonds)
44 Esterifcation…To form the triacylglycerols, you take 3 fatty acids and glycerol…ester formation…
45 Hydrolysis In acid or enzyme hydrolysis, water adds to the ester bonds.triacylglycerols hydrolyze forming glycerol and three fatty acids.a strong acid, such as HCl or H2SO4, or an enzyme catalyst is required.
46 Saponification Fat or oil + strong base glycerol + salts of fatty acids (soap)
47 Hydrogenation of Glyceryl Trioleate In a hydrogenation reaction, H2 adds across the double bond to form a carbon–carbon single bond.
48 Learning CheckDraw (explain) the condensed structural formula of the product of the following reaction.