Biochem Lipids I

1,978
-1

Published on

(c) Geromil J. Lara, RMT, MSMT

Published in: Education, Business, Technology
0 Comments
9 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total Views
1,978
On Slideshare
0
From Embeds
0
Number of Embeds
2
Actions
Shares
0
Downloads
204
Comments
0
Likes
9
Embeds 0
No embeds

No notes for slide

Biochem Lipids I

  1. 1. LIPIDSGeromil J. Lara, RMT, MSMT
  2. 2. LIPIDS• Refers to a collection of organic molecules of varying chemical composition• Are grouped together on the basis of their solubility in nonpolar solvents• 4 main groups – Fatty Acids (Saturated and Unsaturated) – Glycerides (Glycerol-containing Lipids) – Nonglyceride Lipids (Sphingolipids,Steroids,Wax) – Complex Lipids (Lipoproteins) 2
  3. 3. Saturated Fatty Acids Unsaturated Neutral Glycerides Glycerides PhosphoglyceridesLIPIDS Complex Lipids Lipoproteins Sphingomyelins Sphingolipids Glycolipids Nonglycerides Lipids Steroids Waxes 3
  4. 4. BIOLOGICAL FUNCTIONS OF LIPIDS• Energy Source – When oxidized, each gram of fat releases 9 kcal of energy, or more than twice the energy released by oxidation of a gram of carbohydrate• Energy Storage – In the form of triglycerides (TAG) in adipocytes• Cell Membrane Structural Components – Phosphoglycerides, sphingolipids, and steroids make up the basic structure of all cell membranes 4
  5. 5. BIOLOGICAL FUNCTIONS OF LIPIDS• Hormones – Steroid Hormones• Vitamins – Lipid-soluble vitamins (A,D,E, and K)• Vitamin Absorption – Dietary fat serves as a carrier of the lipid-soluble vitamins• Protection – fats as shock absorber• Insulation – subcutaneous fat 5
  6. 6. (1) FATTY ACIDS• Are long-chain O monocarboxylic acids R C OH• Generally contain an even number of #1 Carbon Acid Group carbon atoms O R C OH Polar End - Hydrophilic End Non-polar End - Hydrophobic End (F at-soluble tail) 6
  7. 7. CLASSIFICATIONS OF FATTY ACID• Length of the Carbon Chain – Long-chain, medium-chain, short-chain• Degree of Unsaturation – Saturated, Unsaturated (Mono, Poly)• Location of Double Bonds – Omega-3 Fatty Acid, Omega-6 Fatty Acid 7
  8. 8. (1) FATTY ACIDS• Short-Chain Fatty Acids – Less than 6 carbons• Medium-Chain Fatty Acids – 6-10 carbons• Long-Chain Fatty Acids – More than 12 carbons 8
  9. 9. (1) FATTY ACIDS• Saturated Fatty Acids – Each C being “saturated” with H – General Formula: CH3(CH2)nCOOH 9
  10. 10. LAURIC ACID 10
  11. 11. 11
  12. 12. 12
  13. 13. (1) FATTY ACIDS• Unsaturated Fatty Acids – Composed of at least one carbon-to- carbon double bond – Almost are in the cis configuration 13
  14. 14. (1) FATTY ACIDS• Monounsaturated Fatty Acids (MUFA) – Composed of one carbon-to-carbon double bond 14
  15. 15. 15
  16. 16. (1) FATTY ACIDS• Polyunsaturated Fatty Acids (MUFA) – Composed of more than one carbon-to- carbon double bond 16
  17. 17. (1) FATTY ACIDS• Polyunsaturated Fatty Acids (MUFA) – are identified by position of the double bond nearest the methyl end (CH3) of the carbon chain; this is described as an omega number; – If PUFA has first double bond 3 carbons away from the methyl end = omega 3 FA – 6 carbons from methyl end = omega 6 FA 17
  18. 18. 18
  19. 19. 19
  20. 20. (1) FATTY ACIDS• cis-Fatty Acid – H’s on same side of the double bond; fold into a U-like formation; naturally occurring 20
  21. 21. (1) FATTY ACIDS• trans-Fatty Acid – H’s on the opposite side of the double bond; occur in partially hydrogenated food 21
  22. 22. 22
  23. 23. 23
  24. 24. PROPERTY SATURATED UNSATURATED FATTY ACIDS FATTY ACIDC-C Bonds within Only C-C single At least one C-Cthe hydrocarbon bonds double bond chainHydrocarbon chains are Alkanes Alkenes characteristic of what group of hydrocarbon “Shape” of Linear, Fully Bend in carbonHydrocarbon chain extended chain at site of C-C double bond Physical state at Solid Liquidroom temperature Melting Point Higher Lower 24
  25. 25. 25
  26. 26. 26
  27. 27. BUT, ARE ALL TRANS-FAT BAD?• Omega-3: – Eicosopentaenoic acid (EPA) – Docosahexaenoic acid (DHA) – Alpha-linolenic acid (ALA) • flaxseed--most, canola (rapeseed), soybean, walnut, wheat germ • body can make some EPA and DHA from ALA• Omega-6 – corn, safflower, cottonseed, sesame, sunflow er – Linoleic acid 27
  28. 28. 28
  29. 29. CHEMICAL REACTIONS OF FATTY ACID• Esterification – Fatty acids react with alcohols to form esters and water 29
  30. 30. CHEMICAL REACTIONS OF FATTY ACID• Acid Hydrolysis – Producing fatty acids from esters – Opposite of esterification• Saponification – Is the base-catalyzed hydrolysis of an ester – the product of this reaction, an ionized salt, is a soap • Have a long uncharged hydrocarbon tail and a negatively charged terminus (the carboxylate terminus 30
  31. 31. CHEMICAL REACTIONS OF FATTY ACID• Saponification – Is the base-catalyzed hydrolysis of an ester – the product of this reaction, an ionized salt, is a soap • Have a long uncharged hydrocarbon tail and a negatively charged terminus (the carboxylate terminus), they form micelles that dissolve oil and dirt particles 31
  32. 32. 32
  33. 33. CHEMICAL REACTIONS OF FATTY ACID• Reaction at the Double Bond (Unsaturated Fatty Acids) – Hydrogenation • Used in the food industry to convert polyunsaturated vegetable oils into saturated solid fats – Partial Hydrogenation • Carried out to add hydrogen to some, but not all, double bonds in polyunsaturated oils • In this way liquid vegetable oils are converted into solid form (Crisco and margarine) 33
  34. 34. 34
  35. 35. 35
  36. 36. 36
  37. 37. (2) GLYCERIDES• Are lipid esters that contain the glycerol molecule and fatty acids – 2 Classes • Neutral Glycerides – nonionic and nonpolar • Phosphoglycerides – have polar region, the phosphoryl group, in addition to the nonpolar fatty acid tails 37
  38. 38. (2) GLYCERIDES• Neutral Glycerides – Produce after the esterification of glycerol with a fatty acid – Esterification may occur at one, two, or all three positions, producing: • Monoglycerides • Diglycerides • Triglycerides – most important and main storage form of lipids in man (adipocytes) 38
  39. 39. 39
  40. 40. 40
  41. 41. FAT vs. OIL• Fat – A mixture of triglycerides containing high proportion of long-chain, saturated fatty acids • Animals – generally solids • Plants or Fish – usually liquids• Oil – Liquid fat – Contain high proportion of unsaturated fatty acids and saturated fatty acids 41
  42. 42. (2) GLYCERIDES• Neutral Glycerides – There are no charges (+ or -) on these molecules – These long molecules readily stack with one another and constitute the majority of the lipids stored in the body’s fat cells – Primary function is to store energy • More energy-rich nutrients are consumed than are required for metabolic processes, much of the excess is converted to neutral glycerides and stored as TAG in fat cells 42
  43. 43. (2) GLYCERIDES• Phosphoglycerides – Phospholipids – are group of lipids that are phosphate esters • The presence of the phosphoryl group results in a molecule with a polar head (the phosphoryl group) and a nonpolar tail (the alkyl chain of the fatty acid) 43
  44. 44. (2) GLYCERIDES• Phosphoglycerides – Most abundant membrane lipids and derived from glycerol-3-phosphate – Contain acyl groups derived from long chain fatty acids at C-11 and C-2 of glycerol-3-phosphate – At C-3 the phosphoryl group is joined to glycerol by a phosphoester bond • Phosphatidate – simplest phosphoglyceride contains a free phosphoryl group 44
  45. 45. 4/30/2012 Free Template from www.brainybetty.com 45
  1. A particular slide catching your eye?

    Clipping is a handy way to collect important slides you want to go back to later.

×