These Learning key Points will help when you will study Text Book of Lehninger Principles Of Biochemistry .

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)

6. triacylglycerols

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)

14. Triacylglycerols
triacylglycerols

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

29. 1. Glycerophospholipid
Glycerophospholipid

30. Glycerophospholipid

31. Glycerophospholipid

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

46. Degraded in
lysosomes

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