Lipids

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Lipids

  1. 1. LIPIDS AND FATS <ul><li>*A group of organic substances that are greasy to touch and insoluble to H2O but </li></ul><ul><li>soluble in organics solvents/non-polar solvents such as ether, benzene, alcohol and choloroform. </li></ul>
  2. 2. <ul><li>Contain C,H,O but compared to carbohydrates, have less O2 in proportion to C & H </li></ul><ul><li>Basic structural unit: fatty acids </li></ul><ul><li>Are chemically composed of 5 main elements: C, H,O, N, P. </li></ul><ul><li>Composed of about 5% of the organic matter of the cell. </li></ul>
  3. 3. FATS <ul><li>Simple lipids </li></ul><ul><li>Most concentrated source of energy </li></ul><ul><li>Composed of C, H and O but C is greater in number and ratio of H to O is higher </li></ul><ul><li>Solid at room temperature </li></ul>
  4. 4. OIL <ul><li>Physical state of fats that is liquid at room temperature </li></ul><ul><li>Example: Mineral and lubricating oil from petroleum or oil of cloves </li></ul>
  5. 5. Trigyceride <ul><li>Chemical and clinical names for fats and oils </li></ul><ul><li>Ester of glycerol and fatty acids </li></ul><ul><li>Form of fats found in foodstuff and fat depot of most animals </li></ul>
  6. 6. Glycerol <ul><li>3 carbon chain which makes up the core of fat molecules, such that 1 molecule of fatty acid is attached to each of the 3 carbon unit of glycerol </li></ul>
  7. 7. <ul><li>H - glycerine linkage </li></ul><ul><li>H C OH HOOC R(C  H  ) </li></ul><ul><li>H C OH HOOC R(C  H  ) </li></ul><ul><li>H C OH HOOC R(C  H  ) </li></ul><ul><li>H </li></ul><ul><li>Glycerol Fatty Acid Simple Triglyceride Tristearin </li></ul>
  8. 8. <ul><li>If R 1 R 17 and R 33 are different they are considered mixed triglyceride </li></ul><ul><li>Example </li></ul><ul><ul><li>R 1 C17 H 33 Oleic Acid </li></ul></ul><ul><ul><li>R 2 C17 H 35 Stearic Acid </li></ul></ul><ul><ul><li>R 3 C15 H 31 Palmitic Acid </li></ul></ul>
  9. 9. Functions of Lipids <ul><li>Source of Energy </li></ul><ul><ul><li>Fat as the most concentrated source of energy 9 cal/g </li></ul></ul><ul><ul><li>As adipose tissue, it is the major source of energy stored in quantity by the body </li></ul></ul><ul><ul><li>Fat is converted to acetyl CoA which yields great mount of ATP </li></ul></ul><ul><li>Source of Essential Fatty Acids </li></ul><ul><ul><li>From seed oils of wheat germ, corn soybean, walnut, cotton seeds </li></ul></ul><ul><li>Carrier of Fat soluble vitamins and their precursor </li></ul>
  10. 10. <ul><li>4. Insulation </li></ul><ul><li>subcutaneous layer of fat reduces heat loss in cold weather (helps maintain body temperature) </li></ul><ul><li>Excessive heat layer or subcutaneous fats (obesity) interfere with heat loss during warm weather thereby increasing discomfort </li></ul><ul><li>5. Protection of Vital Body Organs </li></ul><ul><li>-especially from physical shock </li></ul>
  11. 11. <ul><li>6. Palatability </li></ul><ul><ul><li>Responsible for flavors and aroma of foods in the diet </li></ul></ul><ul><ul><li>It stimulates flow of digestive juices </li></ul></ul><ul><li>7. Satiety value </li></ul><ul><ul><li>Fats retard the emptying of the stomach (reduce gastric motility) and stay longer therefore delays the onset of hunger which makes the individual feel satisfied for a longer period of time </li></ul></ul>
  12. 12. <ul><li>8. Acts at emulsifying agent </li></ul><ul><li>Lecithin helps in transport of fatty substances that cannot easily pass through the cell membrane </li></ul><ul><li>9. Lubricants </li></ul><ul><li>Which aid in elimination </li></ul><ul><li>10. Precursor of Prostaglandins </li></ul><ul><li>Participates in the regulation of blood pressure, heart rate and lipolysis </li></ul><ul><li>11. Body Composition </li></ul><ul><li>Female 18-25% of BW Male 15-20% </li></ul>
  13. 13. <ul><li>12. Important constituent of tissue/cell membrane structure (phospholipids, cholesterol) - 30-40% lipids; 60-7-% proteins; RBC – phosphoglycerides </li></ul><ul><li>13. protective form of cell walls of many bacteria; leaves of higher plants; or the exoskeleton of insects and the skin of the vertebrates; </li></ul><ul><li>in animals, the waxes keep feathers, skin and hair soft, pliable and H2O repellant. While the cuticle waxes of plants protect them both from dehydration and from invasion of harmful organisms </li></ul>
  14. 14. <ul><li>14. As enzyme cofactors ( some fat soluble vitamins). </li></ul><ul><li>15. As transport form of some neurotransmitters ex. Acetylcholine </li></ul><ul><li>16. As receptors in nerve ending membranes. </li></ul><ul><li>17. As determinants of immunological specificity </li></ul>
  15. 15. Fatty Acids <ul><li>Consist of a chain series of Carbon attached to a carboxyl group which concerns the acidic property of the compound </li></ul><ul><li>They give a diversity and chemical specificity to the natural fats, similar to that given to proteins by amino acids </li></ul>
  16. 16. Classification of Lipids <ul><li>I. Classification by White – based on the presence or absence of glycerol. </li></ul><ul><li>1. Fatty Acids </li></ul><ul><li>2. Lipids containing glycerol </li></ul><ul><li>a. Neutral fats (triacylglycerols) </li></ul><ul><li>b. Phosphoglycerides </li></ul><ul><li>c. Cardiolipin </li></ul><ul><li>d. Plasmologens </li></ul>
  17. 17. <ul><li>3. Lipids not containing glycerol </li></ul><ul><li>a. Sphingolipids </li></ul><ul><li>b. Aliphatic alcohol and waxes </li></ul><ul><li>c. Terpenes 2 major grps of </li></ul><ul><li>d. Steroids non-saponifiable lipids </li></ul><ul><li>e. Prostaglandins </li></ul><ul><li>4. Lipids combined with other classes of compounds </li></ul><ul><li>a. Lipoproteins and proteolipids </li></ul><ul><li>b. Glycolipids </li></ul>
  18. 18. <ul><li>II. Classification by Bloors: </li></ul><ul><ul><li>Simple Lipids- ester of fatty acids or other alcohol </li></ul></ul><ul><ul><li>1. neutral fats or trigyceride </li></ul></ul><ul><ul><li>3 fatty acids combined with glyceride </li></ul></ul><ul><ul><li>2 fatty acids + glycerol + diglyceride </li></ul></ul><ul><ul><li>1 fatty acid + glycerol + monoglyceride </li></ul></ul><ul><ul><li>simple fats- all fatty acids are the same </li></ul></ul><ul><ul><li>Mixed fats- at least 2 fatty acids are different </li></ul></ul>
  19. 19. <ul><ul><li>2. Waxes-at least 2 fatty acids with an alcohol other than glycerol </li></ul></ul><ul><ul><li>- long chain or cyclic alcohol </li></ul></ul><ul><ul><li>- they are not digested by fat splitting enzyme, so no nutritional value </li></ul></ul><ul><ul><li>- includes esters of cholesterol, Vitamin A and D </li></ul></ul>
  20. 20. <ul><ul><li>B. Compound Lipids </li></ul></ul><ul><ul><li>- esters of fatty acid containing groups in addition to an alcohol and fatty acid (CHO phosphate or nitrogenous group) </li></ul></ul><ul><ul><li>1. Phospholipids </li></ul></ul><ul><ul><li>- fats containing H 3 PO 4 and a nitrogenous base in addition to fatty acid and glycerol </li></ul></ul>
  21. 21. <ul><ul><li>- plays an important role in the transport of fat to the different tissues and appear to be involved in its utilization </li></ul></ul><ul><ul><ul><ul><li>Lecithin- emulsifying agent </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Cephalin- thromboplastic substance which initiates blood coagulation </li></ul></ul></ul></ul>
  22. 22. <ul><li>2. Glycolipids </li></ul><ul><ul><li>- contains carbohydrate and nitrogenous base </li></ul></ul><ul><ul><li>example: Cerebrosides which contain a molecule of glucose or galactose </li></ul></ul><ul><ul><li>3. Aminolipids or lipoproteins </li></ul></ul><ul><ul><li>- lipid molecule bound to protein; facilitate transport in the aqueous medium of blood </li></ul></ul>
  23. 23. <ul><ul><li>C. Derived Lipids </li></ul></ul><ul><ul><li>- derivatives of simple and compound lipids due to hydrolysis. </li></ul></ul><ul><ul><li>- Some contain N or P or both, other contain S </li></ul></ul><ul><ul><li>Fatty Acids </li></ul></ul><ul><ul><li>Glycerol </li></ul></ul><ul><ul><li>Steroids </li></ul></ul><ul><ul><ul><li>Sterols- cholesterol </li></ul></ul></ul><ul><ul><ul><li>Bile Acids- glycocholic acid </li></ul></ul></ul><ul><ul><ul><li>Sex Hormones- progesterone </li></ul></ul></ul><ul><ul><ul><li>Adrenal corticosterol </li></ul></ul></ul><ul><ul><ul><li>Vitamin D </li></ul></ul></ul><ul><ul><ul><ul><li>ergocalciferol (D 1 ) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Cholicalceferol (D 3 ) </li></ul></ul></ul></ul>
  24. 24. FATTY ACIDS <ul><li>Content of fats and oils which are the basis of their physical and chemical properties </li></ul><ul><li>The most abundant occurring lipids </li></ul><ul><li>The building blocks of several classes of lipids and neutral fats, phosphoglycerides, glycolipids, cholesterol esters and some waxes </li></ul><ul><li>Products of fat hydrolysis </li></ul>
  25. 25. A. Structure of Fatty acids <ul><li>1.They are mainly straight chain aliphatic, monocarboxylic acids, ranging in chain lengths from 4 to 24 C atoms. </li></ul><ul><li>2.Type formula </li></ul><ul><li>( hydrophobic – R – COOH – hydrophilic) </li></ul><ul><li>3. FA maybe saturated and unsaturated </li></ul><ul><li>4. Most naturally occurring fatty acids are even numbered containing 16 to 18 C atoms. </li></ul>
  26. 26. <ul><li>5. Double bonds in naturally occurring fatty acids are always in a cis – as opposed to trans – configuration </li></ul><ul><li>a. the presence of the double bond gives rise to the possibility of geometric isomerism </li></ul>
  27. 27. <ul><li>b. the double bond forms around which the rest of the molecules maybe oriented; if the radicals are on the same side of the bond, the compound is called a cis – form; if on opposite sides, a trans – form. </li></ul><ul><li>HOOH(CH2)7CH CH(CH2)7COOH </li></ul><ul><li>CH3(CH2)7CH CH3(CH2)7CH </li></ul><ul><li>cis-oleic acid trans-elaidic acid </li></ul><ul><li>CH3 H CH3 H </li></ul><ul><li>C C </li></ul><ul><li>C C </li></ul><ul><li>H H COO </li></ul><ul><li>COO </li></ul>
  28. 28. Classification of Fatty Acids <ul><li>Essential or indispensable Fatty Acids </li></ul><ul><ul><li>When the body cannot synthesize them from other substance, it must be provided in the diet </li></ul></ul><ul><ul><li>Examples: </li></ul></ul><ul><ul><ul><li>Linoleic Acid- (n-6 PUFA) sole dietary </li></ul></ul></ul><ul><ul><ul><li>Linolenic Acid- (n-3 PUFA) promotes growth </li></ul></ul></ul><ul><ul><ul><li>Arachidonic Acid- promotes growth </li></ul></ul></ul>
  29. 29. <ul><li>Deficiency in the diet produces: </li></ul><ul><li>Impairment of growth </li></ul><ul><li>Some form of dermatitis </li></ul><ul><li>Excessive thirst </li></ul><ul><li>Kidney damage in advance cases </li></ul><ul><li>Some cases of eczema and dermatosis- caused by vit. A deficiency are cured by addition of indispensable FA </li></ul>
  30. 30. <ul><li>2. Unsaturated Fatty Acids </li></ul><ul><li>- if f.a. contains 1 double bond monounsaturated, (oleic) </li></ul><ul><li>if f. a. contains 2 or more double bonds polyunsaturated, (linoleic a., linolenic a., arachidonic a.) </li></ul><ul><li>Unstable and reactive due to the presence of (=) bonds. </li></ul><ul><li>Ends in “enoic” </li></ul>
  31. 31. Most important unsaturated fatty acids: <ul><li>1. Oleic acid (C 18 H 34 COOH) – olive oil </li></ul><ul><li>CH 3 (CH 2 ) 7 CH = CH (CH 2 ) 7 COOH </li></ul><ul><li>2. Linoleic acid (C 18 H 32 COOH) – corn oil </li></ul><ul><li>CH 3 (CH 2 ) 4 CH = CHCH 2 CH </li></ul><ul><li>= CH (CH 2 ) 7 COOH </li></ul><ul><li>3. Linolenic acid (C 18 H 30 COOH) – linseed oil </li></ul><ul><li>CH 3 CH 2 CH = CHCH 2 CH = CHCH 2 CH </li></ul><ul><li>= CHCH (CH 2 ) 7 COOH </li></ul>
  32. 32. Importance of Unsaturated FAcids <ul><li>Maintains normal growth and reproduction of lower animals </li></ul><ul><li>Prevents eczematous lesions of skin in man </li></ul><ul><li>Lowers the serum cholesterol level in man (polyunsaturated type) </li></ul>
  33. 33. 3. Saturated Fatty Acids <ul><li>Fatty acids wherein the C atom holds as many H as it can hold. </li></ul><ul><li>Found in animal and vegetable fats (coconut and peanut oil) </li></ul><ul><li>H H </li></ul><ul><li>C C with w hydrogen atoms attached to each C atom </li></ul><ul><li>H H </li></ul><ul><li>eg,. Stearic Acid, Palmitic acid, myristic acid </li></ul>
  34. 34. <ul><li>Contains up to 8C atoms; belong to acetic acid series w/ general formula of CnH2nO2 </li></ul><ul><li>Saturated fatty acids has no double bonds </li></ul><ul><li>Systematic name ends in “anoic” </li></ul><ul><li>ex. Lauric or duodecanoic – C12 </li></ul><ul><li>myristic or tetradecanoic – C14 </li></ul><ul><li>palmitic or hexadecanoic – C16 </li></ul><ul><li>stearic or octadecanoic – C18 </li></ul>
  35. 35. <ul><li>Classificattion of SFA accdg to the no. of C atoms: </li></ul><ul><li>1. Short chain – w/ < 6 C atoms </li></ul><ul><li>ex. Butanoic – 4 C atoms; pentanoic – 5 C </li></ul><ul><li>2. Medium chain – w/ 6-10 C atoms </li></ul><ul><li>ex. Heptanoic, octanoic, nonanoic, decanoic </li></ul><ul><li>3. Long chain – w/ H and more C atoms </li></ul><ul><li>ex. Dodecanoic, octadecanoic </li></ul>
  36. 36. Nomenclature of Fatty acids <ul><li>1. Delta ( ) system – C atoms are numbered beginning from the carboxylic end (COOH) </li></ul><ul><li>ex. Linoleic acid - 18: 2c 9, 12 </li></ul><ul><li>COOH </li></ul><ul><li>CH3 </li></ul><ul><li>2. N system (Number system) counting starts from the methyl end of the molecule </li></ul><ul><li>ex. Linoleic acid – 18: 2n – 6, 9 </li></ul><ul><li>3. Omega system </li></ul>
  37. 37. Some metabolically important FA: Animal fats C18H36O2 0 18 octadecanoic Stearic Plants & animal fats C16H32O2 0 16 hexadecanoic Palmitic Coconut,nutmeg C14H28O2 0 14 tetradecanoic Myristic Laurel, coconut oil C12H24O2 0 12 duodecanoic Lauric Occurrence Chemical formula No. of = bonds No. of C atoms Systematic name Common name
  38. 38. Lecithin, cephalin, liver, fish C20H32O2 4 20 All cis - 5,8,11,14 eicosatetraenoic Arachidonic Linseed oil C18H30O2 3 18 All-cis-9,12,15 octadecatrienoic Linolenic Linseed oil C18H32O2 2 18 Cis 9 octadecadienoic Linoleic Cottonseed oil C18H34O2 1 18 Cis 9 octadecanoic Oleic Butter, fish, oils, hen fat C16H30O2 1 16 Cis 9 hexadecanoic Palmitoleic
  39. 39. Physical properties of Fatty acids: <ul><li>Odorless, tasteless,colorless, greasy to touch </li></ul><ul><li>Insoluble to water but are soluble in organic solvents such as chloroform, methanol, ether or benzene, carbon tetrachloride </li></ul><ul><li>Only small amounts are present in nature; abundant in amide or ester linkage </li></ul><ul><li>Boiling point and melting point rise w/ inc in chain length;inc. C atoms – inc. melting point – less soluble </li></ul>
  40. 40. <ul><li>5. At physiological ph, fatty acids are ionized and possess amphipathic character ( their hydrocarbon tail is hydrophobic while the carboxylic head (COOH) is hydrophilic. </li></ul><ul><li>6. Solubility decreases (inversely proportional) w/ increasing chain length. FA w/ R groups higher than C6 are only slightly soluble in water. </li></ul><ul><li>7. Specific gravity of fats is less than 0. </li></ul>
  41. 41. Chemical properties of FA due to double bonds: <ul><li>1. Hydogenation- addition of hydrogen; hardening – UFA – hydrogenated by gaseous hydrogen in the presence of catalyst like platinum, palladium or nickel </li></ul><ul><li>* principle involved in the manufacture of artificial butter (oleomargarine) from vegetable oils. </li></ul><ul><li>2. Halogenation – Br and I </li></ul>
  42. 42. <ul><li>3. Oxidation leading to rancidity </li></ul><ul><li>exposure to air – acidic UFA – due to hydrolysis – liberation of volatile FA – formation of peroxides,odoriferous volatile aldehyde, ketones and acids – rancid odor </li></ul><ul><li>Lipoxidase – enzyme causing rancidity of fats and oils at room temperature </li></ul><ul><li>- change maybe catalyzed by bacteria </li></ul>
  43. 43. <ul><li>Types of rancidity </li></ul><ul><li>Hydrolytic rancidity – bad odor and taste are due to the free FA liberated (hydrolysis) </li></ul><ul><li>ex. Butterfat – w/ high %age of volatile FA </li></ul>
  44. 44. <ul><li>Oxidative rancidity – caused by oxidation of UFA and their = bonds w/ the production of shortered chain acids, aldehydes and ketones;more impt. type </li></ul><ul><li>ex. Tallowy butter – dairy industry </li></ul><ul><li>* O2 is necessary for oxidative rancidity. Light, heat, moisture and traces of certain metals such as Cu hasten the oxidative process </li></ul>
  45. 45. Due to COOH (carboxylic acid) <ul><li>1. Esterification – a very slow reaction but maybe accelerated by heat or addition of hydrogen ion </li></ul><ul><li>2. Saponification – metallic salts of fatty acids (soaps) will be produced when treated w/ alkali. </li></ul><ul><li>- Na & K salts are soluble in water </li></ul><ul><li>Na salts – hard soaps </li></ul><ul><li>K salts – soft soaps </li></ul><ul><li>- Ca & Mg salts and the heavy metals such as Pb & Zn are insoluble in water </li></ul><ul><li>3. Hydrolysis – fats are hydrolyzed by dilute acids to FA and glycerol </li></ul>
  46. 46. <ul><li>Assignment: ( Watch LORENZO’S OIL FILM ) </li></ul><ul><li>1. What ails the main character in the story? What are the symptoms presented? </li></ul><ul><li>2. What are the preventive measures/cure given to remedy the problem? </li></ul><ul><li>3. Is there a real cure to Lorenzo’s disease/illness? </li></ul><ul><li>4. What is the mixture of Lorenzo’s oil? </li></ul><ul><li>5. How will you relate the subject Biochemistry in the story? </li></ul><ul><li>Write your answers in a one whole intermediate pad paper. Submission is on Friday. </li></ul><ul><li>We’ll have discussion of Lipids and about the film. </li></ul>

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