Learning Keys , Lehninger Chapter # 10 LIPIDS
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Chapter 10 of 'Lehninger Principles of Biochemistry' focuses on lipids, highlighting their biological importance, types (storage, structural, and signaling lipids), and functions. It details fatty acids, triacylglycerols, phospholipids, sphingolipids, and sterols, along with their roles in energy storage, cellular structure, and signaling processes. The chapter also discusses the significance of vitamins and enzymes involved in lipid metabolism.
![Steroid hormones
• derivatives of sterols
– lack alkyl chain attached to D ring of cholesterol
• SH produced blood stream enter cell binds
to protein protein expression
• [low] enough because of its ↑affinity
• major Steroid hormones:
– sex hormones,
– hormones from adrenal cortex:
• cortisol, aldosterone](https://image.slidesharecdn.com/lehninger4ech10yeni-150502032056-conversion-gate02/85/Learning-Keys-Lehninger-Chapter-10-LIPIDS-57-320.jpg)
Learning Keys , Lehninger Chapter # 10 LIPIDS
- 1. Lehninger Principles of Biochemistry Fourth Edition David L. Nelson and Michael M. Cox Fourth Edition Chapter 10: Lipids Copyright © 2004 by W. H. Freeman & Company
- 2. Biological Importance 1. Fats & oils storage lipids 2. Phospholipids & sterols structural lipids 3. Others i. Cofactorsi. Cofactors ii. Electron carriers iii. Light-absorbing pigments iv. Hydrophobic anchors for proteins v. “chaperone” to help membrane protein fold vi. Emulifying agents in digestive tract vii. Hormones viii. Intracellular messenger
- 3. 1. STORAGE LIPIDS • Fats & Oils derivatives of fatty acids (FA) – FA hydrocarbon triacylglycerols – FA hydrocarbon derviatives like fossil fuel – Burn them exergonic reaction – Two example: triacylglycerols and waxes
- 4. Fatty Acids • FA=Carboxylic acid + hydrocarbon chain(HC) – HC between 4-36 carbon long (C4 to C36) – Saturated HC no double bond – Unsaturated HC one or >one triacylglycerols – Unsaturated HC one or >one – A few has OH, methyl-group branch, rings
- 5. Nomenclature of FA • Palmitic Acid wth 16C, saturated: 16:0 • Oleic Acid wth 18C, one double: 18:1 • To show the position of double bonds triacylglycerols • To show the position of double bonds – ∆ (delta) used: How? ∆no of Catom • Example: # of C=20; # of DB=2, where? between C-9&C-10 C-12&C-13 SO 20:2 (∆∆∆∆9,12)
- 7. Common • most monounsaturated FA ∆9 • Most polyunsaturated FA ∆9,12 or ∆9,15 triacylglycerols
- 8. cis-configuration highly common Trans-configuration: produced by microp of rumen of ruminants And during the hydrogenation of fish and vegetable oils triacylglycerols Trans FA LDL (bad cholesterol)
- 9. Physical properties Depending on # of Carbon & # of double b. The more hydrocarbon the more hydrophobic The fewer double bond the more hydrophobic triacylglycerols The fewer double bond the more hydrophobic The more hydrocarbon the more melting point The higher double bond the lower melting point
- 10. triacylglycerols
- 11. triacylglycerols
- 12. triacylglycerols
- 13. Melting • No double bond – Atoms close each other – Possibility of van der Waals triacylglycerols – Possibility of van der Waals • Size – Carboxyl side is polar; polar/hydrocarbon • Double bond number – Not enough, cis configuration (kink)
- 15. Types of triacylglycerols • Simple triacylglycerols: only one kind of fatty acids (example: 16:0 tristearin) • Mixed triacylglycerol (mostly): 2 or more triacylglycerols • Mixed triacylglycerol (mostly): 2 or more different fatty acids. • Triacylglycerols nonpolar • Lipids lower speicifc gravity than water 2 layers water oil
- 16. Roles of Triacylglycerols • Store energy • Insulation • Stored in cell as oily droplets serving as depots of triacylglycerols • Stored in cell as oily droplets serving as depots of metabolic fuel – adipocytes for vertebrates fat droplets – As oil in seeds of plants • Lipases: enzyme to hydrolyse TA to fatty acids to be transported anywhere as an energy battery
- 17. triacylglycerols
- 18. triacylglycerols
- 19. Why body uses TA to store energy • More reduced than sugar twice energy when hydrolysed • Hydrophobic unhydrated less space but triacylglycerols • Hydrophobic unhydrated less space but higher energy (2 g water/1 g polysaccharide to hydrate it) – 15 kg TA months – Full glycogen depots supply less than one day’s energy
- 20. TA for insulation • TA under skin low temperature – Seals, walruses, penguins etc triacylglycerols – Seals, walruses, penguins etc (warm-blooded polar animals) full of TA – Hibernating animals (bear) both energy and insulation
- 21. triacylglycerols
- 22. Simple and mixed TA in food. So different FA in size and saturation degree triacylglycerols
- 23. Waxes Waxes
- 24. Waxes
- 25. • Function of waxes depends on • Waxes are water repellent • Firm consistency • Waxes for hair pliable (easy to bend), lubricated, waterproof Waxes lubricated, waterproof • Birds’ feather • Tropical plants’ leaves for water loss • Industeial usage • Ointments, lotions and polishes from waxes
- 26. Structural lipids in Membrane • A barrier • A double layer of lipids • Amphipatic (charged and hydrophobic)
- 28. I II III IV V Called Phospholipid Called glycolipidCalled Phospholipid Why? Polar group to hydrophobic moeity by Phosphodiester bond Called glycolipid Why Sugar at polar head
- 32. Fatty Acids • Glycerophospholipid Fatty Acids • Differences in different organism, tissues, even cells Glycerophospholipid • Generally – C-1 to C16 or C18 – C-2 to C18 or C20
- 33. Phospholipids with ether linked fatty acids: Ether lipids Ester •Vertebrate heart tissue (plasmalogen %50 of phospholipids)phospholipids) •Halophilic (salt lovers) bacteria •Cilliated protists •Certain invertebrates
- 35. Galactolipids : plants (most abundant) Localized in thylokoid membrane in chloroplast Make up 70-80% of total membrane lipid No phosphate intake Plants also have sulfolipids (sulfonated glucose to a diacylglycerol in glycosidic linkage) -1
- 37. Archeabacteria’s membrane lipids (Hydrocarbon) Glycerol dialkyl glycerol tetraethers (GDGTs)
- 38. Sphingolipids •4th biggest group •Polar head + 2 nonpolat tail •No glycerol •Majority no phosphate group •Extra sphingosine •Its strucutre: 1 sphingosine + 1 FA + head
- 40. • Three subclass of sphingolipids 1. Sphingomyelins 2. Glycosphingolipids 3. Gangliosides
- 41. • Three subclass of sphingolipids 1. Sphingomyelins – Phosphocholine (polar head group –X) – So called glycerophospholipid (due to phosphate group) – Animal cells – Prominent in myelin sheat around axons 2. Glycosphingolipids2. Glycosphingolipids 3. Gangliosides
- 42. • Three subclass of sphingolipids 1. Sphingomyelins 2. Glycosphingolipids – Generally outer face of plasma membrane – Sugar (1 or 2) to ceramidine wthout phosphate g. – Cerebroside: single sugar – Glucose nonneural tissue – Galactose neural tissue – Globosides: neutral – 2 or more sugar – D-glucose; D-galactose; N-acetyl-D-galactosamine 3. Gangliosides
- 43. • Three subclass of sphingolipids 1. Sphingomyelins 2. Glycosphingolipids 3. Gangliosides – most complex one – Oligosaccharide + N-acetylneuraminic acid (sialic– Oligosaccharide + N-acetylneuraminic acid (sialic acid) – Negative charge due to sialic a. – Accumulated in outer surface of plasma membrane – Kinds and amount change during development
- 47. Sterols • With steroid nucleus ( 4 fused rings; 3X6+1X5) – Planar – Rigid – No rotation– No rotation – Most eukaryotics’ membrane – Plant can synthesize – Animals can do – But bacteria can not (a few exception) – Funciton: some in signaling, in the structure of bile acids (cholestrol)
- 49. Lipids with active role passive role 1. Potent signals (hormones) 2. Enzyme cofactor (in cellular respiration and photosynthesis and in transfer of sugar moeties) • Vitamines –A, D, E ,K 3. Pigment molecules (to absorb light to see (eye) or to produce chemical energy (leaf), colorization (orange of carrot) 4. volatile lipids (communication of plants)
- 50. Phosphatidylinositol: Regulate metabolism •Phosphatidylinositol and its phosphorylated derivatives: phosphatidylinositol 4,5- bisphosphate inositol 1,4,5-trisphosphate (IP3) •some regulatory proteins binds to phosphatidylinositol 3,4,5-bisphosphate •source of intracellular messengers.
- 51. Eicosanoids • Paracrine hormone (near point) • involved in – Reproduction– Reproduction – inflammation – Pain – Fever – Formation of blot clots – Regulation of blood pressure – Gastric acid segration – Etc
- 54. • Prostaglandins: prostate gland – Two known groups – PGE ether-soluble (subgroups PGE1 ...) – PGF water soluble – Regulation of cAMP • Regulation of celular and tissue functions
- 55. • Thromboxanes – By thrombocytes • In blood clotting
- 56. • Leukotrienes – in leukocytes – Powerful signals – leukotriene D4, contraction of the muscle lining the airways to the lung. – Overproduction asthmatic attacks – strong contraction of smooth m. of lung (anaphylactic shock) potentially fatal allergic reaction in individuals hypersensitive to bee stings, penicillin, or other agents
- 57. Steroid hormones • derivatives of sterols – lack alkyl chain attached to D ring of cholesterol • SH produced blood stream enter cell binds to protein protein expression • [low] enough because of its ↑affinity • major Steroid hormones: – sex hormones, – hormones from adrenal cortex: • cortisol, aldosterone
- 58. male sex hormone organ: testis female sex h ovary and placenta regulation of glucose metabolism regulation of salt extraction both from adreanl cortex synthetic drug for inflammation potent growth regulator in vascular plants
- 59. Volatile Signals • lipophilic compound for plant to….. – attrack pollinators and helpful organisms against enemiesagainst enemies – repel herbivors – communicate with friends – exmple: josmante
- 60. Vitamins • vitamins essential (mostly not produced by animals, most in diet) • grouped into two• grouped into two – soluble in polar s. (water-soluble vitamins) – soluble in nonpolar solvent(fat-soluble v) • A,D,E,K: isoprenoid compounds by condansation of poly-isoprene units
- 61. Vitamin D3 • cholecalciferol – from skin from 7-dehydrocholesterol • ultiately converted to 1,25-d,hydroxyvitamin D33 – hormone which regulates …….. • calcium uptake by intestine • calcium level in kidney and bones – interact directly with its target protein in nucleus • deficincy defective bone formation and rickets • vitamin D2 by yeast and similar effect like D3 – added into milk
- 62. Vitamin A • retinol • various forms functioning as….. – hormone such as retinoic acid • receptor of cell nucleus to regulate gene in epithelial• receptor of cell nucleus to regulate gene in epithelial cell development – visual pigment as retinal • initiate response of rop and cone to light • sources: fish oil, liver,egg,milk, butter • beta-carotene: pigments that gives carrots, sweet potatoes, yellow veetables • Syptoms:dryness in skin,eyes and mocous, night blidness
- 64. •Tocopherols •Aromatic ring + along isoprenoid side chain •Hydrophobic so associate with •Cell membrane •Lipid droplets •Lipoproteins •Antioxidant because of its aromatic ring •Sources: egg, vegetable oil, white germ •Deficiency rare; symp: RBC fragility
- 65. •A cycle of oxidation & reduction during the formation of•A cycle of oxidation & reduction during the formation of active protrombin •active protrombin: an enzyme converting fibrinogen to fibrin • fibrin: insoluble protein holding bloot clot together •Deficiency rare; only in new borns •Source: green plants, K2 intestinal bacteria
- 71. Working with Lipids • First degradation – Alkali – Acidic– Acidic – Hydrolytic enzymes • Glycosidase • phospholipase
- 72. Working with Lipids • Extraction – Neutral lidips (TG, waxes)by the solvents • Ethyl ether, chloroform, benzen (hydrophobic) – Membrane Lidips by more polar solvents • Ethanol, methanol – Example: chloroform, ethanol, water (1:2:0.8) – Then add water » Two layers:lipids in chloroform
- 73. Seperation by.. •Adsorption chromotography •Silica gel: polar but insoluble •Polar lipids adsorb to silica gel •Neutral Lipids eluted •To remove polar lipids polar solvents: •For polar, uncharged:acetone •Charged: methanol •TLC: •Very similar to Ad. Ch.•Very similar to Ad. Ch. •Plate with silica •Neutral lipids run faster •Trick in staining lipids •Spray(a dye: RHODAMINE) •Đodine fumes: yellow-brown •Đnteract with double bond •Other commercials