LAB Exp 6. Lipids Flashcards
(159 cards)
1
Q
T/F: lipids are water soluble; they are nonpolar
A
T;F
2
Q
T/F: lipids are soluble to organic solvents
A
T
3
Q
Examples of organic solvents where lipids are soluble
A
Diethyl ether
Dichloromethane
Acetone
4
Q
Building block of complex lipids
A
Fatty acyls
5
Q
Long-chain monocarboxylic acids
A
Fatty acids
6
Q
Long hydrophobic tail and a polar head
A
Fatty acids
7
Q
Fatty acids differ in terms of (3)
A
Degree of unsaturation
Length of HC tails
Position of double bonds
8
Q
Identify whether saturated or unsaturated fatty acid: contains only single C-C bonds
A
Saturated
9
Q
Identify whether saturated or unsaturated fatty acid: CnH2n+1COOH
A
Saturated
10
Q
Identify whether saturated or unsaturated fatty acid: without C=C bond
A
Saturated
11
Q
Identify whether saturated or unsaturated fatty acid: waxy solids at RT
A
Saturated
12
Q
Identify whether saturated or unsaturated fatty acid: animal fats
A
Saturated
13
Q
Identify whether saturated or unsaturated fatty acid: high melting points
A
Saturated
14
Q
Identify whether saturated or unsaturated fatty acid: contains one or more C=C bonds
A
Unsaturated
15
Q
Identify whether saturated or unsaturated fatty acid: CnH2n-1, CnH2n-3COOH, CnH2n-5COOH
A
Unsaturated
16
Q
Identify whether saturated or unsaturated fatty acid: liquids at RT
A
Unsaturated
17
Q
Identify whether saturated or unsaturated fatty acid: vegetable fats
A
Unsaturated
18
Q
Identify whether saturated or unsaturated fatty acid: low melting points
A
Unsaturated
19
Q
T/F: naturally occurring unsaturated fats have trans- orientation
A
F
20
Q
Where does the bend insert in unsaturated fatty acids?
A
HC chain
21
Q
The higher the number of carbons, the ____ the melting point
A
Higher
22
Q
In the case of same number of carbon atoms, the higher the number of double bonds, the _____ the melting point
A
Lower
23
Q
A group of signal lipids
A
Eicosanoids
24
Q
Derived from the metabolism of arachidonic acid by the enzyme cyclooxygenase (COX)
A
Eicosanoids
25
Derived mainly from arachidonic acid
Protaglandins
26
Have a variety of potent biological activities of hormonal or regulatory nature
Prostaglandins
27
Parent compound is prostanoic acid
Prostaglandins
28
Control blood pressure
Prostaglandins
29
Stimulate muscle contration
Prostaglandins
30
Inhibit platelet aggregation
Prostaglandins
31
Induce inflammation
Prostaglandins
32
Induces platelet aggregation and vasoconstriction
Thromboxane A
33
Aspirin and other NSAIDs inhibit the synthesis of _____
Thromboxanes
34
T/F: leukotrienes are synthesized from arachidonic acid
Leukotrienes
35
Leukotrienes as _____ double bonds
3
36
Produce muscle contractions, especially in the lungs and thereby can cause asthma-like attacks
Leukotrienes
37
T/F: leukotrienes are 20 times more potent than histamine
F (100 times)
38
Comprise the bulk of storage fat
Glycerolipids
39
A type of glycerolipid formed by esterification of three fatty acids to glycerol
Triacylglycerol
40
T/F: triacylglycerol is also known as neutral lipid
T
41
Reaction of a TAG with a base producing glycerol and three molecules of fatty acids
Saponification
42
Most abundant lipid in most membrance
Phosphoacylglycerol
43
Have polar head and two nonpolar tails
Phosphoacylglycerol
44
Control cell permeability
Phosphoacylglycerol
45
Other term for phosphatidylcholine
Lecithin
46
Abundant in brain and nerve tissue
Phosphatidylcholine (lecithin)
47
Found in egg yolk, wheat germ, yeast
Phosphatidylcholine (lecithin)
48
Other term of phosphatidylethanolamine
Cephalin
49
Other term for diphosphatidylglycerol
Cardiolipin
50
The only antigenic lipid so far
Cardiolipin/diphosphatidylglycerol
51
The second large class of membrane lipids
Sphingolipids
52
Abundant in nervous system
Sphingolipids
53
Sphingomyelin contain _____ or _____ as their polar head
phosphocholine or phosphoethanolamine
54
Sphingomyelin is most commonly found in _____
Myelin sheath
55
A carbohydrate is bound to an alcohol group of a lipid by a glycosidic linkage
Glygolipids
56
"sterol alcohols"
Sterol lipids
57
Signals molecules located along the membrane
Sterol lipids
58
Contains aromatic alcohol which are derivatives of steroid nucleus
Steroids
59
Steroids has ____ cyclohexane rings and ___ cyclopentane ring
3, 1
60
Precursor for the synthesis of other steroids
Cholesterol
61
Derived from squalene
Cholesterol
62
A C30 terpenoid HC
Squalene
63
T/F: cholesterol is strongly amphipathic
F (weakly amphipatic)
64
T/F: cholesteryl esters are non-hydrolyzable
F
65
Terpenes, carotenoids, quinones, hydroquinone are examples of ___
Prenol lipids
66
Identify the prenol lipid: isoprene derived natural metabolite
Terpenes
67
Identify the prenol lipid: insect and plant growth hormone
Terpenes
68
Identify the prenol lipid: plant's pleasant odors
Terpenes
69
Identify the prenol lipid: lipid-like sugar carriers
Terpenes
70
Fatty acid with a sugar backbone
Saccharolipid
71
Has glucosamine precursoe
Saccharolipid
72
Secondary metabolites of living organisms for survival
Polyketides
73
Used as anti-microbial, anti-parasitic, and anti-cancer
Polyketides
74
Doxycycline and aflatoxin are examples of _____
Polyketides
75
Esters of fatty acids with long chain alcohols
Waxes
76
Enumerate the saponifiable lipids (with fatty acids)
TAGs
Sphingolipids
Waxes
Phosphoacylglycerols
Glycolipids
77
Enumerate the non-saponifiable lipids (without fatty acids)
Steroids
Terpenes
Prostaglandins
Leukotrienes
Thromboxanes
78
What are the fat-soluble vitamins?
A, D, E, K
79
Identify the fat-soluble vitamin: an isoprenoid alcohol that plays a key role in vision
A
80
Identify the fat-soluble vitamin: control of animal growth
A
81
Identify the fat-soluble vitamin: stimulation of development of nervous system
A
82
Identify the fat-soluble vitamin: can either be consumed in diet or biosynthesize from b-carotene
A
83
Enumerate some examples of Vitamin A sources
cod liver oil, fish livers, butter, eggs
84
Identify the fat-soluble vitamin: regulation of Ca & P metabolism
D
85
Identify the fat-soluble vitamin: deficiency leads to ricketsia
D
86
Identify the fat-soluble vitamin: can also be found in cod liver oil and dairy products
D
87
The most abundant form of Vitamin D is ____
D3 (Cholecalciferol)
88
Identify the fat-soluble vitamin: has an antioxidant role
E
89
Identify the fat-soluble vitamin: prevents attack of peroxides on unsaturated fatty acids in membrane lipids
E
90
Identify the fat-soluble vitamin: found in eggs & vegetable oils
E
91
Enumerate the common sources of Vitamin E
corn, peanut, wheat germ
92
Other term Vitamin E
a-tocopherol
93
Identify the fat-soluble vitamin: deficiency leads to muscular dystrophy
E
94
Identify the fat-soluble vitamin: deficiency leads creatinuria
E
95
Identify the fat-soluble vitamin: deficiency leads to anemia
E
96
Identify the fat-soluble vitamin: important in the lymphatic synthesis of prothrombin & protein factors in blood platelets
K
97
Identify the fat-soluble vitamin: Vitamin K found in animals & bacteria
Vitamin K2 (menaquinone)
98
Identify the fat-soluble vitamin: Vitamin K found in plants
Vitamin K1 (phylloquinone)
99
Identify the fat-soluble vitamin: deficiency leads to diminished intestinal absorption of lipids
K
100
Identify the reagent for isolation of lipids: denatures the proteins and disrupts the lipoprotein complexes of the egg yolk
Ethanol
101
Identify the reagent for isolation of lipids: used to remove neutral or least polar lipids
Hexane
102
Identify the reagent for isolation of lipids: provides mild hydration condition
Acetone
103
Identify the reagent for isolation of lipids: the H2O content decreases and extracts the fatty acids, sterol, and other simple lipids
Acetone
104
Identify the reagent for isolation of lipids: the remaining polar lipids with some neutral lipids are further precipitated
Acetone
105
Stationary phase in column chromatography
Silica gel
106
Enumerate the mobile phase in column chromatography
1. petroleum ether: ethyl ether (9:1) - least polar
2. 5% MeOH in DCM
3. DCM:MeOH:H2O (1:3:1) - most polar
107
Describe the result of the first eluate in ester test
Deep burgundy (++); due to fatty acids of TAG
108
Describe the result of the second eluate in ester test
Deep burgundy (+/-); due to cholesterol ester
109
Describe the result of the third eluate in ester test
Deep burgundy (-); due to fatty acids of sphingolipids or phosphoacylglycerol
110
Describe the result of the first eluate in glycerol test
Burnt fat odor (++); presence of glycerol
111
Describe the result of the second eluate in glycerol test
(-)
112
Describe the result of the third eluate in glycerol test
Burnt fat odor (+); presence of glycerol
113
Describe the result of the first eluate in liebermann-burchard test
(-)
114
Describe the result of the second eluate in liebermann-burchard test
Emerald green (+); due to cholesterol
115
Describe the result of the third eluate in liebermann-burchard test
(-)
116
Stationary phase of TLC in lipids
Silica G-250
117
Enumerate the reagents for TLC in lipids
1. Petroleum ether: methanol: H2O (65:25:4)
2. Petroleum ether: methanol: NH4OH (65:25:4)
118
Enumerate the visualizing agents of TLC in lipids
I2
Ninhydrin
119
This visualizing agent appears as yellow-brown spots
I2; due to oxidation of unsaturated fatty acids
120
This visualizing agent appears as blue-violet spots
Ninhydrin; due to free amino groups
121
Enumerate the standards for TLC in lipids
cholesterol, lecithin
122
Purpose of hydroxamic test
Detects the presence of carboxylic acid ester (TAGs, glycerophospholipids, cholesteryl esters)
123
Reagents for hydroxamic test
ethanol:buthanol (3:1); NH2OH x HCl;
NaOH;
FeCl3;
HCl
124
Positive result for hydroxamic test
Burgundy color
125
Principle of hydroxamic test
Complexation reaction
126
Purpose of acrolein test
Detects the presence of glycerol (TAGs, glycerophospholipids)
127
Positive result for acrolein test
Burnt fat odor
128
Reagent for acrolein test
KHSO4, water bath
129
Principle involved in acrolein test
dehydration and oxidation
130
Purpose of liebermann-burchard test
Detects the presence of unsaturated sterols (cholesterol)
131
Reagents for liebermann-burchard test
Conc. H2SO4, acetic anhydride
132
Positive result for liebermann-burchard test
Emerald green solution
133
Principle involved in liebermann-burchard test
Esterification of OH at C-3 with acetic anhydride and epimerization of double bond at C-5
134
Purpose of kraut's test
Detects the presence of choline (phosphatidyl choline, sphingolipids)
135
Reagents for kraut's test
Bismuth nitrate, 3M HNO3, KI (Kraut's reagent)
136
Positive result for kraut's test
Dark orange to red ppt
136
Principle involved in kraut's test
Complexation reaction
Proposed condensation, dehydration, and epimerization
Modification of Dragendorff's test
137
A test for alkaloids
Dragendorff's test
138
Purpose for Ascorbic acid method
Detects the presence of phosphate (phospholipids)
139
Reagents for Ascorbic acid method
6M HNO3, 6M NaOH, Molybdate reagent, 0.1M Ascorbic acid solution
140
Principle of ascorbic acid method
Ammonium molybdate and pottasium antimonyl tartrate react in acid medium with orthophosphate to form a heteropoly acid - phosphomolybdic acid - that is reduced to intensely colored molybdenum blue by ascorbic acid
141
Purpose of ninhydrin test
Detects the presence of a-amino group
142
Reagents for ninhydrin test
Triketohydrindene hydrate (ninhydrin in EtOH)
143
Positive result for ninhydrin test
Blue-violet solution
144
Principle of ninhydrin test
Oxidative deamination followed by condensation
145
Purpose of bromine/iodine test
Detects the presence of double bonds; degree of unsaturation
146
Reagents for test for lipid unsaturation
5% bromine / iodine solution
147
Positive result for bromine/iodine test
Loss of reddish brown color - Iodine
Loss of violet coloration - bromine
148
Identify the lipid index: number of mg of KOH required to saponify the free and combined fatty acids in 1g of a given fat
Saponification number
149
Identify the lipid index: indicates the molecular weight and is inversely proportional to it
Saponification number
150
Identify the lipid index: Number of grams of iodine absorbed by 100mg of fat
Iodine number
151
Identify the lipid index: a measure of degree of unsaturation of a fat
Iodine number
152
Identify the lipid index: number of mg of KOH required to neutralize the fatty acids in a gram of a fat
Acid number
153
Identify the lipid index: indicates the degree of rancidity of a fat
Acid number
154
An additional test for lipids that detect the presence of sugar moiety
Molisch test
155
Reagents for molisch test
1% ethanolic a-naphthol, conc H2SO4
156
Positive result for molisch test
Violet ring at the interface
157
Principle involved in molisch test
Hydrolysis, dehydration, and condensation reaction
158
Molisch test is positive for ____ and _____
Cerebrosides and gangliosides
