PROBLEMS CH 17

Learning Check Which lipids contain the alcohol glycerol? A. steroids and waxes B. triacylglycerols and glycerophospholipids C. sphingolipids and glycerophospholipids D. glycerophospholipids and waxes

Solution Which lipids contain the alcohol glycerol? A. steroids and waxes B. triacylglycerols and glycerophospholipids C. sphingolipids and glycerophospholipids D. glycerophospholipids and waxes Answer is B. Triacylglycerols and glycerophospholipids contain the alcohol glycerol.

Learning Check Assign 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 acid B. stearic acid C. linoleic acid

Solution Stearic 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°Csaturated A. oleic acid mp 13°C unsaturated with one double bond C. linoleic acid mp −17°C unsaturated with two double bonds

Learning Check Draw the condensed structural formulas for each of the fatty acids with 10 carbon atoms that follow. A. saturated B. monounsaturated omega-3 C. monounsat urated omega-6

Solution Draw the condensed structural formulas for each of the fatty acids with 10 carbon atoms that follow. A. saturated CH 3 —CH 2 —CH 2 —CH 2 —CH 2 —CH 2 —CH 2 —CH 2 —CH 2 —COOH B. monounsaturated omega-3 C. monounsat urated omega-6

Learning Check What are the fatty acids in the following triacylglycerol?

Solution Stearic acid Oleic acid Myristic acid

Learning Check Draw the condensed structural formula for glyceryl tripalmitoleate (tripalmitolein).

Solution Draw the condensed structural formula for glyceryl tripalmitoleate (tripalmitolein).

Which of the following products is obtained from the complete hydrogenation of glyceryl trioleate? B. glyceryltristearate Solution

Olestra, a Fat Substitute Olestra is used in foods as an artificial fat. composed of 6–8 long-chain fatty acids attached by ester links to a sucrose (not glycerol) molecule. not broken down in the intestinal tract.

Learning Check Identify each statement as true (T) or false (F). A. There are more unsaturated fats in vegetable oils. B. Vegetable oils have higher melting points than fats. C. Hydrogenation of oils converts some cis-double bonds to trans-double bonds. D. Animal fats have more saturated fats.

Solution Identify each statement as true (T) or false (F). T A. There are more unsaturated fats in vegetable oils. F B. Vegetable oils have higher melting points than fats. T C. Hydrogenation of oils converts some cis- double bonds to trans-double bonds. T D. Animal fats have more saturated fats.

What products are obtained from the complete hydrolysis of glyceryl trioleate? A. glycerol and 3 oleic acids B. glyceryl tristearate C. glycerol and 3 stearic acids Learning Check

What products are obtained from the complete hydrolysis of glyceryl trioleate? A. glycerol and 3 oleic acids Solution

Learning Check Draw the condensed structural formula of the product of the following reaction.

Solution

Learning Check Identify each as a fatty acid, triacylglycerol, amino alcohol or glycerophospholipid. A. glyceryl trioleate B. cephalin C. choline D. palmitic acid

Solution Identify each as a fatty acid, triacylglycerol, amino alcohol or glycerophospholipid. A. glyceryl trioleate triacylglycerol B. cephalinglycerophospholipid C. cholineamino alcohol D. palmitic acid fatty acid

Learning Check Identify the components and type of glycerophospholipid. O ║ CH 2 —O—C— (CH 2 ) 16 —CH 3 O ║ CH 2 —O—C— (CH 2 ) 16 —CH 3 + O NH 3 ║ │ CH 2 —O—P—O—CH 2 —CH−COO – │ O –

Solution Identify the components and type of glycerophospholipid. O ║ CH 2 —O—C— (CH 2 ) 16 —CH 3 O 2 Stearic acids ║ CH 2 —O—C— (CH 2 ) 16 —CH 3 + O NH 3 ║ │ Type = cephalin CH 2 —O—P—O—CH 2 —CH−COO – │ Serine O – Phosphate Amino alcohol

Learning Check Match the components of the cholesterol molecule with each of the following: alkyl chain hydroxyl group steroid nucleus methyl group A C B D

Solution Match the components of the cholesterol molecule with each of the following: alkyl chain hydroxyl group steroid nucleus methyl group A C B D D A C B

Learning Check Identify each of the following as a steroid, triacylglycerol, phospholipid, or sphingolipid. A. cholesterol B. glycerol, 2 fatty acids, phosphate, and choline C. glyceryl tristearate D. sphingosine, fatty acid, phosphate, and choline E. estradiol F. bile salts G. lipids in plasma membranes

Solution A. cholesterolsteroid B. glycerol, 2 fatty acids,phospholipid phosphate, and choline C. glyceryl tristearatetriacylglycerol D. sphingosine, fatty acid, sphingolipid phosphate, and choline E. estradiolsteroid F. bile salts steroid G. lipids in plasma phospholipid membranessphingolipid

Learning Check What is the transport of particles across a cell membrane from high concentration to low concentration called? A. facilitated transport B. diffusion (passive transport) C. active transport

Solution What is the transport of particles across a cell membrane from high concentration to low concentration called? A. facilitated transport B. diffusion (passive transport) C. active transport