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SWBAT: 1.Describe a lipid 2.Describe the classes of lipids SWBAT: 1.Describe a lipid 2.Describe the classes of lipids Chapter 15 Lipids.

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Presentation on theme: "SWBAT: 1.Describe a lipid 2.Describe the classes of lipids SWBAT: 1.Describe a lipid 2.Describe the classes of lipids Chapter 15 Lipids."— Presentation transcript:

1 SWBAT: 1.Describe a lipid 2.Describe the classes of lipids SWBAT: 1.Describe a lipid 2.Describe the classes of lipids Chapter 15 Lipids

2 What are lipids? Group of molecules not defined by structure but by common characteristics They are: non-polar soluble in non-polar solvents like methylene chloride, gasoline, ether not soluble in polar solvent like water fats, oils, fatty acids, waxes, steroids, cholesterol, fat soluble vitamins

3 Lipids and Health BMI: Body Mass Index: Body Fat vs Obesity Blood Lipids

4 CAD: Coronary Artery Disease Lipid deposits clogging arteries in the body and heart Risk Factors for CAD Hypertension, Diabetes, elevated cholesterol smoking sedentary lifestyle stress obesity male sex family history older age

5 Types of Lipids Saponifiable Lipids: Prostaglandins Waxes Tricylglycerols Glycerophospholipids Non-Saponifiable Lipids: Cholesterol Steroid hormones Can be Hydrolyzed Can NOT be Hydrolyzed

6 Homework Chapter 15.1 Pg 497 #15.2 – 15.4 (even)

7 SWBAT: 1.Write structures of fatty acids 2.ID saturated and unsaturated fatty acids Chapter 15 Fatty Acids

8 Fatty Acids Contains a long carbon chain attached to a carboxylic acid on C1 Typically contain and even number of carbon atoms – between 10 and 20 Dodecanoic Acid Lauric Acid

9 Fatty Acids They are: Aliphatic molecules – they are both hydrophobic and hydrophilic But…overall they are hydrophobic HydrophilicHydrophobic Cell Membrane

10 Fatty Acids to know… Laura, My Palm Stinks! Lauric Acid (C12) Myristic Acid (C14) Palmitic Acid (C16) Stearic Acid (C18)

11 Types of Fatty Acids Saturated Fatty Acids: Only single bonds between the carbon atoms Monounsaturated Fatty Acids: Have one double bond in the carbon chain Polyunsaturated Fatty Acids: Have two or more double bonds

12 Unsaturated Fatty Acids trans double bonds cis double bonds

13 Shapes of Unsaturated Fatty Acids

14 Fatty Acids: Physical Properties Saturated and trans Fatty Acids: High melting points (solids) Perfect alignment – high Van de Waals intermolecular attractions Trans fatty acids do not naturally exist – they are a man made product and are the most stable fatty acids

15 Fatty Acids: Physical Properties Unsaturated cis Fatty Acids: Lower melting point (liquid at room temp) Do not have perfect alignment due to kinks in chain – low Van de Waals Less stable – double bonds can break

16 Both are: C 18 H 36 O 2 Saturated MP of 69° Unsaturated MP of 13°

17 Prostaglandins They are: Small polyunsaturated Fatty Acids that act like hormones mediating a range of symptoms from inflammation to blood pressure Synthesized from Arachidonic Acid (AA)

18 Prostaglandins Most have a hydroxyl group on C11 and C15 and a trans double bond at C13 PGE - those with a ketone on C9 PGF - those with a hydroxyl group on C9

19 Inflammation is a… Natural response to infection and injury Disease like rheumatoid arthritis (inflammation of the joints)

20 Why do we care?

21 Non Steroidal Anti- Inflammatory Drugs (NSAIDs) Drug class that includes: Aspirin Ibuprofen Naproxen (Alveve) Ketoprofen (actron) Nabumetone (Relafen) Long term use can result in liver, kidney and gastrointestinal damage

22 NSAID effect and side effect Stomach side effect Video Links

23 Homework Chapter 15.2 Pg 503 #15.6 – 15.18 (even)

24 SWBAT: 1.Write structural formula of wax, fat or oil 2.ID the reaction of a fatty acid and an alcohol or glycerol Chapter 15 Waxes, Fats and Oils

25 Waxes Found in many plants and animals (leaves, stems, skin, fur and feathers) Is an ester of a saturated Fatty Acid and a long-chain alcohol (14-30 carbon atoms)

26 Fats and Oils: Triacylglycerols The body stores Fatty Acids as fats and oils Also called tryglycerides Produced by esterification of glycerol and Fatty Acid groups

27 Fats and Oils: Triacylglycerols Most fats and oils are mixed triacylglycerolds with two or three different Fatty Acids from stearic acid from palmitic acid from myristic acid can be saturated or unsaturated

28 Writing Structures for Triacylglycerol Each Fatty Acid is attached by an ester bond to one of the hydroxyl groups in glycerol Alcohol Part: In triglycerides always glycerol Carboxylic Acid Part: Three Fatty Acids

29 Fats and Oils: Physical Properties A fat is a solid at room temperature (fats in meat, butter, cheese) There are exceptions Typically from an animal source Oil is usually liquid at room temperature (oils – olive, peanut, sunflower) Typically from a plant source

30 Fats and Oils: Physical Properties Saturated Fatty Acids have higher melting points because they pack together tightly Animal fats usually contain more saturated Fatty Acids than vegetable oils

31 Melting Points

32 Homework Chapter 15.3 Pg 507-508 #15.20 – 15.28 (even)

33 SWBAT: Draw the structure of the product from a reaction of triacylglycerol with hydrogen, or an acid or base Chapter 15 Chem Props of Triacylglycerols

34 Hydrogenation Hydrogenation of unsaturated fats converts carbon-carbon double bonds to single bonds Hydrogen gas is heated through oil with a nickel catalyst Partial hydrogenation changes oil to a soft, semisolid fat (crisco) H2H2

35 Why? Chemical process patented in the 1940’s used to convert oil surpluses from soybean farming into spreadable fats (margarines) to alleviate butter shortage

36 Problem… Incomplete hydrogenation leads to the formation of trans- double bonds→ Trans Fats Trans Fats raise LDL (bad cholesterol ) levels in the body Consumption of Trans Fats is correlated with a rise in CAD during 1960-2000 FDA prohibits use of Trans Fats & requires labeling trans fats in our food Video Link

37 Hydrolysis Breaking the ester bond – yielding fatty acid & glycerol First step in the digesting of triglycerides in the body Carried out by the enzyme lipase Glycerol is soluble in water Fatty Acids are not H+H+ lipase

38 Saponification (sapon = soap) Reacting triglycerides with a strong base Yields glycerol and Fatty Acid Salts (soap) Glycerol tritearate + 3 NaOH glycerol + 3 sodium stearate

39 What is Soap Soaps are aliphaic molecules that have a polar part (facing water molecules) and a non- polar part (facing greasy dirt) Ancient soap making – Animal fats are heated with a strong base (lye from burnt limestone) Fatty acid salts – Sodium paltmitate: Na + - OOC-(CH 2 ) 14 -CH 3 Soap Making Video

40 Food Labels


42 Olestra Fatty Acids from cottonseed or soybean oils Composed of 6 to 8 long- chain Fatty Acids attached to sucrose rather than glycerol We can’t digest it so “Fake Fat” goes straight through our system GI problems occurred 

43 Homework Chapter 15.4 Pg 512-513 #15.30 – 15.36 (even)

44 SWBAT: 1.Describe the characteristics of glycerophospholipids Chapter 15 15.5 Glycerophospholipids

45 What are Glycerophospholipids? Similar to triglycerides except one hydroxyl group is replaced by the ester of phosphoric acid and an amino alcohol Bonded through a phosphodiester bond Glycerophospholipids Triglycerides

46 Amino Alcohols Three amino alcohols found in glycerophospholipids are: choline ethanolamine serine

47 Lecithins Lecithins contain choline Fatty Acids can be same, different, saturated, unsaturated or mixture Abundant in: brain tissue nerve tissue egg yolks wheat germ yeast

48 Cephalins Cephalins contain ethanolamine and sometimes serine Abundant in: brain tissue nerve tissue egg yolks wheat germ yeast

49 Polar? Contain both polar and nonpolar regions Ionized alcohol and phosphate portion is called “the head” –Can hydrogen bond with water Two Fatty Acids represent “the tail” Hydrophobic Tails Hydrophilic Head Group

50 Polar and Nonpolar Regions Most abundant in lipids in cell membrane Nonpolar Tails Polar Head

51 Homework Chapter 15.5 Pg 515 #15.38 – 15.42

52 SWBAT: Describe the structure of steroids Chapter 15 Cholesterol & Steroid Hoemones

53 General Structure Steroidnucleus: Three cyclohexane rings A,B,C One cyclopentane ring D

54 Types of Steroids Cholesterol Lipoproteins Steroid Hormones Anabolic Steroids

55 Why does it have the ending –ol? Cholesterol Most abundant steroid in the body

56 Facts about Cholesterol its part of every cell membrane insulates nerve and brain tissue forms bile for digestion forms Vitamin D in skin starting material for steroid hormones: sex hormones, cortisone leads to heart attacks

57 Lipid Metabolism Cholesterol is so important that the body does not rely on what you eat…. It manufactures 80% of the cholesterol needed Serum Cholesterol Levels in your body can be measured via blood tests: Lipid Panels

58 Lipid Panels What health care professional look for… Total Cholesterol HDL: High density Cholesterol – “good” LDL: Low density Cholesterol – “bad”

59 Why? Lowering Cholesterol Levels is a business…. Food industry: fat free/cholesterol free items lean meats low fat dairy hunt against saturated fats Pharmaceutical industry: statin drugs HMG-CoA reductase inhibitors

60 LIPITOR The most widely used drug in the world… Pharmaceutical drug lowering cholesterol levels Reaps 26 billion in sales per year worldwide Side effects range from diabetes, to cancer

61 Cholesterol Levels Cholesterol levels show individual variations due to: Genetics Age General health: cholesterol is an anti- inflammatory, anti-stress substance, it can rise due to reasons ranging from stress, lack of sleep, drugs and chronic diseases (diabetes) Diet: Plant based diets are correlated with lower cholesterol levels

62 Cholesterol in Food Egg250 mg Crab/Shrimp150 mg Beef85 mg White chicken75 mg Fish40 mg All animal based food contain cholesterol All plant based foods contain no cholesterol

63 Cholesterol and CAD Artheriosclerosis is the main cause of CAD It is caused by plaque that clog arteries Plaque are cholesterol deposits Q: What makes cholesterol form plaque? A: Inflammation

64 Transporting Fats in Blood Lipids are insoluble in the blood (=water) Lipids are transported from spherical vesicles called Lipoproteins Skin: Phospholipids, Proteins Inside: Cholesterol, Triglycerides

65 Steroid Hormones Sex Hormones Estrogen: development of female sex characteristics Testosterone: development of male sex characteristics including muscle anabolism Progesterone: prepares uterus for fertilized egg

66 Steroid Hormones Corticosteroids Steroid Hormones produced by the adrenal glands Natural – Cortisone Drug – Prednisone Helps with: stress response immune response regulation of inflammation

67 Anabolic Steroids Synthetic Testosterone derivatives Promote muscle growth, reduce body fat Short term side effects: broken bones, ruptured tendons, kidney pain Long term use lead to kidney, heart, liver damage Legal steroid Tren

68 Homework Chapter 15.6 Pg 522 #15.44 – 15.54 (even)

69 SWBAT: 1.Describe the composition and function of the lipid bilayer in cell membranes Chapter 15 15.7 Cell Membranes

70 Cell Membrane Composed of phospholipid bilayer Polar head & nonpolar tails Semipermeable – items can enter and leave

71 Lipid Bilayer Double row arrangement of phospholipids Hydrophilic polar heads align on outer edges of membrane Hydrophobic nonpolar tails move to center

72 Fluid Mosaic Model Lipid bilayer contains unsaturated Fatty Acid Cis double bonds causes a non-rigid structure In liquid like bilayer: Proteins Carbohydrates Cholesterol

73 Homework Chapter 15.7 Pg 524 – 525 #15.56 – 15.62

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