Organism. Organ and organ systems. Tissue. Cells. Carbohydrates Proteins Lipids Nucleic Acids

Transcription

1 hemistry of Life rganism rgan and organ systems Tissue ells arbohydrates Proteins Lipids Nucleic Acids Hydrocarbons, Alcohols, Phenols, Ethers, Thiols, Aldehydes, Ketones, arboxylic Acids, Esters, Amines, Amides Molecules (compounds) Bonds - ionic, covalent, hydrogen Atom (elements)

2 hemistry of Life - Goals At the end of this chapter you should: be able to identify the different classes of lipids. know the difference between saturated and unsaturated fatty acids. be able to describe the effect of chain length and unsaturation on the melting point of fatty acids. know the difference between fats and oils and be able to describe how the fatty acid composition determines the physical properties of fats and oils. be familiar with the hydrolysis and saponification reactions of triglycerides. be able to describe the properties of glycerophospholipids and their role in the structure of cell membranes. be able to describe the role of cholesterol in human health. be familiar with the role of lipoproteins in transporting lipids and know the difference between LDL and HDL particles. be familiar with the importance of lipids in human health.

3 Lipids - it s role in health oronary Artery Disease (AD) - aka coronary heart disease (HD), ischemic heart disease (IHD), arteriosclerotic cardiovascular disease (ASVD). aused by the deposition and build up of fatty deposits (atherosclerosis: from the greek athera meaning porridge and sclerosis meaning hardening) Risk factors: - Hypertension - Diabetes - Elevated cholesterol - smoking - Sedentary lifestyle - Stress - besity - Male sex - Family history - lder age

4 Lipids - it s role in health - What are triglycerides? - What is HDL? - What is LDL? - How are there molecules made? what is their chemistry?

5 Lipids (from the greek lipos meaning fat or lard) - types Lipids are a class of molecules that are insoluble in water but are soluble in non-polar organic solvents. Lipids Saponifiable lipids (can be hydrolyzed) non-saponifiable lipids (can NT be hydrolyzed) - Waxes - Triglycerides - Steroids - Prostaglandins - Glycerophospholipids - Sphingolipids - Glycosphingolipids Remember the esters?

6 Lipids - types Saponifiable lipids - (can be hydrolyzed) Remember the esters? long chain alcohol Waxes G l y c e r o l G l y c e r o l P 4 Amino alcohol Triglycerides Glycerophospholipids S p h i n g o s i n e P 4 Amino alcohol Sphingolipids S p h i n g o s i n e Sugar Glycosphingolipids

7 Lipids - types nonsaponifiable lipids - (can NT be hydrolyzed) Steroids holesterol Bile salts A 10 9 B 8 7 D Hormones Steroid Ring Structure H Prostaglandins Arachidonic acid yclooxygenase (x-1 and x-2) H H (prostaglandin H2)

8 Lipids - saponifiable, fatty acids in common Saponifiable lipids - (can be hydrolyzed) Remember the esters? long chain alcohol Waxes G l y c e r o l G l y c e r o l P 4 Amino alcohol Triglycerides Glycerophospholipids S p h i n g o s i n e P 4 Amino alcohol Sphingolipids S p h i n g o s i n e Sugar Glycosphingolipids

9 Lipids - s Palmitic acid (hexadecanoic acid) - a saturated fatty acid found in palm oil, butter, cheese, milk. H Stearic acid (octadecanoic acid) - a saturated fatty acid from plant and animal fats and oils. H H Linoleic acid - a poly unsaturated fatty acid from plant and animal fats and oils. An omega-6 fatty acid. H Linolenic acid - a poly unsaturated fatty acid from fish oil, flax seed, hemp seed, and canola oil. An omega-3 fatty acid.

10 Lipids - s, solubility Tail Water soluble polar hydrophilic (water liking) H Water insoluble Non polar hydrophobic (water fearing) Head group The hydrophobic tail is responsible for the fatty or oily characteristics of fatty acid containing lipids

11 Lipids - s, solubility and micells The hydrophobic tails associate into the structure. The hydrophilic head group points towards the water. Held together by weak dispersion forces. Micelles

12 Blast from the past - why are these fat soluble? Lycopene Hydrophobic beta-carotene H 3 H H 3 H 3 H 3 H 3 H 3 H 3 H 3 H 3 H 3 H H 3 H 3 Vitamin E H 3 H 3 H 3 H 3 H H 3 Retinoic acid Retinal H 3 H 3 H 3 H 3 H 3 * H 3 Retinol H 3 Vitamin K(phylloquinone)

13 Lipids - s, they are not flat Palmitic acid (hexadecanoic acid) - a saturated fatty acid found in palm oil, butter, cheese, milk. H Stearic acid (octadecanoic acid) - a saturated fatty acid from plant and animal fats and oils. H H Linoleic acid - a poly unsaturated fatty acid from plant and animal fats and oils. An omega-6 fatty acid. H Linolenic acid - a poly unsaturated fatty acid from fish oil, flax seed, hemp seed, and canola oil. An omega-3 fatty acid.

14 Lipids - s, three dimensional shape

15 Lipids - s, three dimensional shape

16 Lipids - s, some examples and their properties

17 Lipids - s, unsaturation and packing

18 Lipids - s, fish oils and the heart H docosahexaenoic acid (DHA) H eicosapentaenoic acid (EPA) Polyunsaturated fatty acids (PUFAs), learn more at the AHA

19 Lipids - s, trans fatty acids and health The process that is used to convert polyunsaturated vegetable oils (liquids) to partially hydrogenated solid fats to be used in margarine and shortening produces trans fats. H 3 H 2 H H 2 H H 3 H 3 H 2 H H H 2 H 2 H 2 H 3 H H partial hydrogenation cis-2,5-octadiene trans-3-octene Learn more qbout Trans s at: (1). The FDA (2). About Trans s in butter and margarine at the AHA (2). About Trans s and heart disease at the AHA s are thought to (1). Increase the levels of LDL (Low Density Lipoproteins) (2). Reduces the levels of HDL (high Density Lipoproteins)

20 Lipids - s, those that are essential H Linoleic acid - a poly unsaturated fatty acid from plant and animal fats and oils. An omega-6 fatty acid. H Linolenic acid - a poly unsaturated fatty acid from fish oil, flax seed, hemp seed, and canola oil. An omega-3 fatty acid. H Arachidonic acid These fatty acids cannot be synthesized in the body. Need to get them from our diet.

21 Lipids - Waxes H 3 (H 2 ) 18 (H 2 ) 19 H 3 Jojoba wax H 3 (H 2 ) 14 Bees wax (H 2 ) 29 H 3 H 3 (H 2 ) 24 (H 2 ) 29 H 3 arnauba wax

22 Lipids - Fats and ils Fats and ils - are esters of glycerol. Also known as triglycerols or triglycerides. s in the body are stored as triglycerides. Triglycerides that are (usually) liquids at room temperature are oils. Triglycerides that are solids at room temperature are fats. G l y c e r o l H 2 H H 2 (H 2 ) 16 H 3 (H 2 ) 16 H 3 (H 2 ) 16 H 3 Triglycerides Glyceryl tristearate

23 Lipids - Fats and ils, triglycerides H 2 H H (H 2 ) 16 H 3 H H 2 H H + H (H 2 ) 16 H 3 H (H 2 ) 16 H 3 Esterification Glycerol stearic acid Three of them. ne for each alcohol group. Ester group H 2 (H 2 ) 16 H 3 H (H 2 ) 16 H 3 H 2 (H 2 ) 16 H 3 Glyceryltristearate

24 Lipids - Fats and ils, triglycerides Alcohol Part arboxylic acid part In triglycerides always Glycerol H 2 H (H 2 ) 16 H 3 (H 2 ) 16 H 3 Three fatty acids H 2 (H 2 ) 16 H 3 Glyceryltristearate In Glyceryltristearate all three fatty acids are the same. But they do not have to be... H 2 H H 2 (H 2 ) 16 H 3 (H 2 ) 14 H 3 (H 2 ) 12 H 3 from stearic acid from Palmitic acid from Myristic acid Saturated fats Unhealthy In Glyceryltristearate all three fatty acids are saturated. But they do not have to be... H 2 H (H 2 ) 16 H 3 (H 2 ) 7 H H(H 2 ) 5 H 3 from stearic acid from Palmitoleic acid unsaturated fats H 2 (H 2 ) 12 H 3 from Myristic acid

25 Lipids - Fats and ils, triglycerides Triglycerides from animal sources are usually solids at room temperature - they are called Fats. There are exceptions the most notable being the triglycerides from fish. Triglycerides from animal plant sources are usually liquids at room temperature - they are called oils. Think back to the melting points of different fatty acids. an you predict what types of fatty acids are prevalent in animal vs. plant triglycerides?

26 Lipids - Fats and ils, triglycerides Physical properties H 2 (H 2 ) 16 H 3 hydrophobic tail H (H 2 ) 7 H H(H 2 ) 5 H 3 H 2 (H 2 ) 12 H 3 Ester group not as hydrophillic as the fatty acid carboxyl group. verall more hydrophobic than fatty acids. Do not form micells. ompare To hydrophilic Head group hydrophobic Tail H

27 Lipids - Fats and ils, triglycerides hemical properties What groups do you think will determine the chemical properties of triglycerides? Ester group H 2 (H 2 ) 16 H 3 Alkene group H (H 2 ) 7 H H(H 2 ) 5 H 3 H 2 (H 2 ) 12 H 3 The ester and alkene functional groups will determine the chemical properties of triglycerides.

28 Lipids - Fats and ils, triglycerides hemical properties, Hydrolysis H 3 Ester + H 2 Heat/H + H 3 H + H 3 H H 3 carboxylic acid Alcohol H 2 H H 2 (H 2 ) 16 H 3 (H 2 ) 7 H (H 2 ) 12 H 3 H(H 2 ) 5 H 3 H 2 / acid H 2 H H 2 H H H + H H H (H 2 ) 16 H 3 (H 2 ) 7 H (H 2 ) 12 H 3 H(H 2 ) 5 H 3 Triglycerol - the ester Triglycerol - the alcohol s - the carboxylic acids

29 Lipids - Fats and ils, triglycerides hemical properties, saponification H 3 + NaH H 3 H 3 - Na + + H 3 H Ester carboxylate ion Alcohol H 2 H H 2 (H 2 ) 16 H 3 (H 2 ) 7 H (H 2 ) 12 H 3 H(H 2 ) 5 H 3 NaH H 2 H H 2 H H H + + Na - + Na - + Na - (H 2 ) 16 H 3 (H 2 ) 7 H (H 2 ) 12 H 3 H(H 2 ) 5 H 3 Triglycerol - the ester Triglycerol - the alcohol Salts of the s - the salts of the carboxylic acids These are soaps oconut shampoo - which oil does this come from?

30 Lipids - Fats and ils, triglycerides hemical properties, Hydrogenation H2 (H2)7H H(H2)5H3 H (H2)7H H(H2)5H3 H2 (H2)12H3 H2/Ni H2 (H2)14H3 H (H2)7H H2 (H2)12H3 Partial hydrogenation Used to convert vegetable oils to produce spreadable fats (like margarine). auses the production of trans fats. Learn more qbout Trans Fats at: (1). The FDA (2). About Trans s in butter and margarine at the AHA (2). About Trans s and heart disease at the AHA Trans Fats are thought to (1). Increase the levels of LDL (Low Density Lipoproteins) (2). Reduces the levels of HDL (high Density Lipoproteins) H(H2)5H3

31 Trans Fats: oming in 2006, to a label near you...

32 Trans Fats: oming in 2006, to a label near you...

33 Lipids - Fats and ils, the hunt for new fats The glycerol molecule in triglycerides had three alcohol groups to form esters. What other molecules have we seen with multiple alcohol groups? H 2 = fatty acid Fatty Acid Acid Fatty Fatty Acid Acid Fatty H 2 Fatty Acid Fatty Acid Acid Fatty lestra - a fat substitute made by combining sucrose with fatty acids no enzymes to break it down, large size prevents absorption. ontributes no calories. May lead to lipid soluble vitamin (A, D, E and K) deficiency.

34 Lipids - Fats and ils, triglycerides - What are triglycerides? Are triesters of glycerol and fatty acids. - those that are liquid at room temperature are oils. - those that are solids at room temperature are Fats. - triglycerides have chemical properties of esters and alkenes. - triglycerides are the major source of energy storage of animals. - triglycerides with a high content of saturated fatty acids or with trans fatty acids are unhealthy.

35 Lipids - types Saponifiable lipids - (can be hydrolyzed) Remember the esters? long chain alcohol Waxes G l y c e r o l G l y c e r o l P 4 Amino alcohol Triglycerides Glycerophospholipids S p h i n g o s i n e P 4 Amino alcohol Sphingolipids S p h i n g o s i n e Sugar Glycosphingolipids

36 Lipids - Glycerophospholipids G l y c e r o l P 4 Amino alcohol ompare To G l y c e r o l Glycerophospholipids Triglycerides In glycerophospholipids one of the hydroxyl groups in glycerol is bonded to a phosphate (P 4 ) via an ester link. The phosphate is in turn linked to another alcohol (usually an amino alcohol), via another ester link. These lipids are also known as phospholipids.

37 Lipids - Glycerophospholipids G l y c e r o l P 4 Amino alcohol glycerol H 2 H H 2 P - Fatty Acids (H 2 ) 7 H (H 2 ) 7 H H(H 2 ) 5 H 3 H(H 2 ) 5 H 3 H 3 H 2 H 2 N + H 3 H 3 phosphate amino alcohol (choline) H 2 (H 2 ) 7 H H(H 2 ) 5 H 3 H (H 2 ) 7 H H(H 2 ) 5 H 3 H 3 H 2 P H 2 H 2 N + H 3 - H 3 Ester links (phosphodiester)

38 Lipids - Glycerophospholipids H 2 (H 2 ) 7 H H(H 2 ) 5 H 3 H (H 2 ) 7 H H(H 2 ) 5 H 3 H 3 H 2 P amino alcohol H 2 H 2 N + H 3 - H 3 H 3 H H 2 H 2 N + H 3 H 3 H H 2 H 2 NH 3 + H H 2 H NH holine (quatenary ammonium ion) Ethanolamine Serine

39 Lipids - Glycerophospholipids H 2 (H 2 ) 7 H H(H 2 ) 5 H 3 H (H 2 ) 7 H H(H 2 ) 5 H 3 H 3 H 2 P H 2 H 2 N + H 3 - H 3 phosphatidyl choline A typical phosphoglyceride (glycerophospholipid). Also called lecithin. All phosphoglycerides that contain a choline are called lecithins. The fatty acids can be the same or differet. an be saturated or unsaturated or can be a mixture.

40 Lipids - Glycerophospholipids Physical properties H 2 (H 2 ) 7 H H(H 2 ) 5 H 3 hydrophobic tails H (H 2 ) 7 H H(H 2 ) 5 H 3 H 3 H 2 P H 2 H 2 N + H 3 - H 3 hydrophillic head group The negatively charged phosphate and the positively charges ammonium group make the head group hydrophillic. Glycerophospholipids form micells. H 2 (H 2 ) 16 H 3 hydrophobic tail H H 2 (H 2 ) 7 H (H 2 ) 12 H 3 H(H 2 ) 5 H 3 hydrophilic Head group hydrophobic Tail H

41 Lipids - Glycerophospholipids The 3D structure Palmitoyl leoyl phosphatidyl choline

42 Lipids - and cell membranes

43 Lipids - and cell membranes Lipid membranes are fluid - they permit movement of proteins and lipids. Lipid membranes (Bilayers) typically contain: Phosphatidylcholine Phosphatidylethanolamine Phosphatidylserine Sphingomyelins Glycerophospholipids

44 Lipids (from the greek lipos meaning fat or lard) - types Lipids are a class of molecules that are insoluble in water but are soluble in non-polar organic solvents. Lipids Saponifiable lipids (can be hydrolyzed) non-saponifiable lipids (can NT be hydrolyzed) - Waxes - Triglycerides - Steroids - Prostaglandins - Glycerophospholipids - Sphingolipids - Glycosphingolipids Remember the esters?

45 Lipids - nonsaponifiable - Steroids - they have the same distinguishing feature of the saponifiable lipids, i.e. they do not dissolve in water. BUT their structures are completely different D A B Steroid Ring Structure The most important and most abundant steroid is cholesterol.

46 Lipids - nonsaponifiable, cholesterol holesterol is a sterol H 3 H 3 H 3 H(H 2 ) 3 HH 3 H 3 H component of cell membranes component of myelin sheath, nerve and brain tissue used in the synthesis of other steroids including steroid hormones, bile salts, and vitamin D etc.

47 Lipids - nonsaponifiable, cholesterol in a membrane Hydrophilic H Hydrophobic H3 H3 H3 H3 H(H2)3HH3 holesterol helps maintain the fluidity of the membrane. Acts as a buffer that does not allow big changes in membrane fluidity.

48 Lipids - cholesterol in steroid hormone synthesis H 3 H 3 H 3 H 3 H 3 H(H 2 ) 3 HH 3 H 3 H 3 H 3 H 3 H 3 H H holesterol Pregnenolone Progesterone H H 3 H 2 H H H H H 2 H H 3 H H 3 H 3 H 3 ortisol aldosterone testosterone

49 The steroid hormones Progesterone Prepares uterus for fertilized egg testosterone Development of male organs; male sexual characteristics; sperm formation ortisol (a glucocorticoid) Stimulated glycogen synthesis from amino acids and increased blood glucose levels. Inhibits allergic and inflammatory responses. aldosterone (a mineralocorticoid) Helps maintain Na and K balance in tissues; water retention.

50 Lipids - cholesterol and bile salts H 3 H 3 H 3 H 3 H 3 H 3 H(H 2 ) 3 HH 3 H 3 H(H 2 ) 3 HH 3 H H 3 HH 2 H 2 - H 3 H 3 Many steps H 3 H H H H H holesterol 7alpha-hydroxycholesterol holic acid H 3 H 3 H H 3 HH 2 H 2 NH H 2 H 2 S 3 - Hydrophilic H H 3 HH 2 H 2 NH H 2 - Hydrophilic H 3 H 3 H H Hydrophobic H H Hydrophobic Taurocholic acid Glycocholic acid Bile satls (the salts of the acid) - derived from cholesterol; are made in the liver and stored in the gallbladder; secreated in to the intestine after meals to solubilize fats. The contain both hydrophobic and hydrophilic parts and therefore act as very good detergents. The micelles help break up fat in the diet so that they can be broken down.

51 Lipids - cholesterol, the dark side holesterol is a major constituent of atherosclerotic plaques.

52 Lipids - cholesterol, a summary - What is cholesterol? - cholesterol is a lipid that is a steroid, a compound that contains a steroid nucleus. - cholesterol is a sterol because it contains a H group. - cholesterol is a sterol because it contains a H group. - cholesterol is a major constituent of cellular membranes and helps membrane maintain its rigidity. - cholesterol is needed for the synthesis of other important steroid hormones like progesterone and testosterone, and also for the synthesis of bile salts. - cholesterol is a major component of atherosclerotic plaques and therefore plays an important role in heart disease.

53 Lipids - transporting If triglycerides (the major storage molecule of fatty acids) and cholesterol are mainly hydrophobic (non-soluble in water) then how are they transported in the blood which is mainly water? Use lipoprotein particles. transports lipids from intestine to cells for use as energy and for storage. transports lipids from liver to cells for use as energy and for storage. transports lipids to cells to be used in cell membranes, synthesis of steroids. Excess LDL causes cholesterol to deposit in plaques. transports excess lipids from cells to liver to be converted to bile salts and eliminated.

54 Lipids - transporting - What are LDLs and HDLs? - Low density lipoproteins (LDLs) and High density lipoproteins (HDLs) are lipid/protein particles that are responsible for the transport of lipids in the blood. - LDLs are bad cholesterol, because the cholesterol within the LDL can be deposited in plaques. - HDLs are good cholesterol, because they help remove excess cholesterol to the liver to be eliminated.

55 Lipids - nonsaponifiable, prostaglandins Why are they nonsaponifiable? H Arachidonic acid yclooxygenase (x-1 and x-2) ~ 20 others H H (prostaglandin H2) - involved in almost every phase of the reproduction. - involved in blood clotting. - involved in inflammation and pain.

56 Lipids (from the greek lipos meaning fat or lard) - types Lipids are a class of molecules that are insoluble in water but are soluble in non-polar organic solvents. Lipids Saponifiable lipids (can be hydrolyzed) non-saponifiable lipids (can NT be hydrolyzed) - Waxes - Triglycerides - Steroids - Prostaglandins - Glycerophospholipids - Sphingolipids - Glycosphingolipids Remember the esters?