17 5 Phospholipids are a family of lipids

Glycerophospholipids contain • two fatty acids that form ester bonds with the first and

Sphingomyelin • contains sphingosine instead of glycerol. • contains a fatty acid, phosphate, and

Amino Alcohols Amino alcohols found in glycerophospholipids • are choline, serine, and ethanolamine. •

Lecithin and Cephalin Lecithin and cephalin are two types of glycerophospholipids that are •

Structure and Polarity of a Glycerophospholipids • contain both polar and nonpolar regions that

Structure and Polarity of a Glycerophospholipid (a) The components of a typical glycerophospholipid: an

Glycerophospholipid, Snake Venom The venom of the eastern diamondback rattlesnake and the Indian cobra

Study Check Draw the condensed structural formula for the cephalin that contains two stearic

Solution Draw the condensed structural formula for the cephalin that contains two stearic acids,

Study Check Identify each of the following as a fatty acid, triacylglycerol, amino alcohol,

Solution Identify each of the following as a fatty acid, triacylglycerol, amino alcohol, or

Sphingomyelin contains • sphingosine, a long-chain amino alcohol that replaces glycerol. • an amide

Sphingomyelins are abundant in the white matter of the myelin sheath, a coating surrounding

Sphingomyelin Structure of a sphingomyelin containing myristic acid and choline. General, Organic, and Biological

Study Check Palmitic acid, the 16 -carbon saturated fatty acid, is the most common

Solution Palmitic acid, the 16 -carbon saturated fatty acid, is the most common fatty

Slides: 19

Download presentation

17. 5 Phospholipids are a family of lipids similar in structure to triacylglycerols; they include glycerophospholipids and sphingomyelin. G l y c e r o l Fatty acid PO 4 Amino alcohol Glycerophospholipid Learning Goal Draw the structure of a phospholipid containing glycerol or sphingosine. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Glycerophospholipids contain • two fatty acids that form ester bonds with the first and second hydroxyl groups of glycerol. • a hydroxyl group that forms an ester with phosphoric acid, which forms another phosphoester bond with an amino alcohol. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake G l y c e r o l Fatty acid PO 4 Amino alcohol © 2016 Pearson Education, Inc.

Sphingomyelin • contains sphingosine instead of glycerol. • contains a fatty acid, phosphate, and an amino alcohol. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake S p h i n g o s i n e Fatty acid PO 4 Amino alcohol © 2016 Pearson Education, Inc.

Amino Alcohols Amino alcohols found in glycerophospholipids • are choline, serine, and ethanolamine. • are ionized at physiological p. H of 7. 4. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Lecithin and Cephalin Lecithin and cephalin are two types of glycerophospholipids that are • abundant in brain and nerve tissues. • found in egg yolk, wheat germ, and yeast. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Structure and Polarity of a Glycerophospholipids • contain both polar and nonpolar regions that allow them to interact with polar and nonpolar substances. • have a polar head containing the ionized amino alcohol and phosphate portion, which is strongly attracted to water. • have a nonpolar hydrocarbon tail portion soluble only in nonpolar substances such as lipids. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Structure and Polarity of a Glycerophospholipid (a) The components of a typical glycerophospholipid: an amino alcohol, phosphoric acid, glycerol, and two fatty acids. (b) In a glycerophospholipid, a polar “head” contains the ionized amino alcohol and phosphate, while the hydrocarbon chains of two fatty acids make up the nonpolar “tails. ” (c) A simplified drawing indicates the polar region and the nonpolar region. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Glycerophospholipid, Snake Venom The venom of the eastern diamondback rattlesnake and the Indian cobra contains phospholipases, which are enzymes that • catalyze the hydrolysis of the fatty acid on the center carbon of glycerophospholipids in the red blood cells. • produces a lysophospholipid, which causes the breakdown of the red blood cell membranes. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Study Check Draw the condensed structural formula for the cephalin that contains two stearic acids, phosphate, and serine as the ionized amino alcohol. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Solution Draw the condensed structural formula for the cephalin that contains two stearic acids, phosphate, and serine as the ionized amino alcohol. ANALYZE THE PROBLEM Given cephalin, two stearic acids (18: 0), phosphate, serine (ionized) General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake Need condensed structural formula © 2016 Pearson Education, Inc.

Solution Draw the condensed structural formula for the cephalin that contains two stearic acids, phosphate, and serine as the ionized amino alcohol. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Study Check Identify each of the following as a fatty acid, triacylglycerol, amino alcohol, or glycerophospholipid: A. B. C. D. glyceryl trioleate cephalin choline palmitic acid General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Solution Identify each of the following as a fatty acid, triacylglycerol, amino alcohol, or glycerophospholipid: A. B. C. D. glyceryl trioleate cephalin choline palmitic acid General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake triacylglycerol glycerophospholipid amino alcohol fatty acid © 2016 Pearson Education, Inc.

Sphingomyelin contains • sphingosine, a long-chain amino alcohol that replaces glycerol. • an amide bond formed by the amine group on sphingosine to a fatty acid. • a hydroxyl group that forms an ester bond with phosphate, which forms another phosphoester bond to choline or ethanolamine. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Sphingomyelins are abundant in the white matter of the myelin sheath, a coating surrounding the nerve cells that increases the speed of nerve impulses and insulates and protects the nerve cells. In multiple sclerosis, • sphingomyelin is lost from the myelin sheath, which protects the neurons in the brain and spinal cord. • the myelin sheath deteriorates as the disease progresses. • scars form on the neurons and impair the transmission of nerve signals. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Study Check Palmitic acid, the 16 -carbon saturated fatty acid, is the most common fatty acid found along with the ionized amino alcohol choline in the sphingomyelin of eggs. Draw the condensed structural formula for this sphingomyelin. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Solution Palmitic acid, the 16 -carbon saturated fatty acid, is the most common fatty acid found along with the ionized amino alcohol choline in the sphingomyelin of eggs. Draw the condensed structural formula for this sphingomyelin. ANALYZE THE PROBLEM Given sphingomyelin, palmitic acid (16: 0), choline (ionized) General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake Need condensed structural formula © 2016 Pearson Education, Inc.

Solution Palmitic acid, the 16 -carbon saturated fatty acid, is the most common fatty acid found along with the ionized amino alcohol choline in the sphingomyelin of eggs. Draw the condensed structural formula for this sphingomyelin. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.