Lecture Presentation Chapter 17 Lipids Karen C Timberlake General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Chapter 17 Lipids A clinical lipid specialist • assesses a patient’s current diet and exercise program • diagnoses and determines treatment including dietary changes • advises patients on the use of medications that lower lipid levels General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Chapter 17 Readiness Core Chemistry Skills • Writing Equations for Hydrogenation, Hydration, and Polymerization (12.7) • Naming Alcohols and Phenols (13.1) • Naming Carboxylic Acids (16.1) • Hydrolyzing Esters (16.5) General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc 17.1 Lipids Lipids are • biomolecules that contain fatty acids or a steroid nucleus • soluble in organic solvents but not in water • named for the Greek word lipos, which means “fat.” • an important feature in cell membranes, fat-soluble vitamins, and steroid hormones Steroid Nucleus Learning Goal Describe the classes of lipids General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Types of Lipids Lipids are characterized by their structures: Lipids such as • waxes, • triacylglycerols, • glycerophospholipids, and • sphingolipids are esters that can be hydrolyzed to give fatty acids and other molecules General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Lipids Containing Glycerol Triacylglycerols and glycerophospholipids contain the alcohol glycerol General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Lipids Containing Sphingosine Sphingolipids contain the amino alcohol sphingosine General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Lipids Containing Sphingosine Steroids, which have a completely different structure, not contain fatty acids and cannot be hydrolyzed They are characterized by the steroid nucleus of four fused carbon rings General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc General Structure of Lipids Lipids are naturally occurring compounds in cells and tissues They are soluble in organic solvents but not in water General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Study Check Lipids are characterized by presence of fatty acids or a steroid nucleus Which type is described by the following? A contain a fused four-membered ring system B contain long carbon chains C include carboxyl groups General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Chemistry Link to Health: Anabolic Steroids Anabolic steroids • are derivatives of testosterone • are used illegally to increase muscle mass • have side effects including fluid retention, hair growth, sleep disturbance, and liver damage General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Adrenal Corticosteroids Steroid hormones called adrenal corticosteroids • are produced by the adrenal glands located on the top of each kidney • include aldosterone, which regulates electrolytes and water balance by the kidneys • include cortisone, a glucocorticoid, which increases blood glucose level and stimulates the synthesis of glycogen in the liver General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Adrenal Corticosteroids 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, steroid, or triacylglycerol: A B C D E cholesterol stearic acid glyceryl tristearate estradiol contains no fatty acids 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, steroid, or triacylglycerol: A B C D E cholesterol steroid stearic acid fatty acid glyceryl tristearate triacylglycerol estradiol steroid contains no fatty acids steroid General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc 17.7 Cell Membranes Substances are transported across a cell membrane by either diffusion, facilitated transport, or active transport Learning Goal Describe the composition and function of the lipid bilayer in cell membranes General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Cell Membranes Cell membranes • are semipermeable so that nutrients can enter the cell and waste products can leave • separate cellular contents from the external environment • consist of a lipid bilayer made of two rows of phospholipids • have an inner portion made of the nonpolar tails of phospholipids, with the polar heads at the outer and inner surfaces General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Fluid Mosaic Model, Cell Membrane In the fluid mosaic model of a cell membrane, • proteins and cholesterol are embedded in a lipid bilayer of phospholipids • the bilayer forms a membrane-type barrier with polar heads at the membrane surfaces and the nonpolar tails in the center, away from the water General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Fluid Mosaic Model, Cell Membrane The lipid bilayer • contains phospholipids with unsaturated fatty acids with kinks in the carbon chains • contains proteins, carbohydrates, and cholesterol molecules • is not a rigid, fixed structure but one that is dynamic and fluid-like • has proteins and carbohydrates on the surface that communicate with hormones and neurotransmitters General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Transport through Cell Membranes The transport of substances through cell membranes involves • diffusion (passive transport), which moves particles from a higher to a lower concentration • facilitated transport, which uses protein channels to increase the rate of diffusion • active transport, which moves ions against a concentration gradient General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Transport Pathways through Cell Membranes Substances are transported across a cell membrane by diffusion (passive) transport, facilitated transport, or active transport General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Study Check The transport of particles across a cell membrane from high concentration to low concentration is called A facilitated transport B diffusion C active transport General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Solution The transport of particles across a cell membrane from high concentration to low concentration is called B diffusion General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Concept Map General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc ... and therefore are NOT soluble in water General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc General, Organic, and Biological Chemistry: ... prostaglandins that produce inflammation and pain in the area General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Prostaglandins:... makes it insoluble in water General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C Timberlake © 2016 Pearson Education, Inc Prostaglandins Prostaglandins • are hormone-like