Lipids Flashcards

1
Q

Lipids are a family of substances that are ____ in water but ____ in nonpolar and low polarity solvents such as diethyl ether, acetone, and DCM.

soluble or insoluble

A

insoluble; soluble

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2
Q

A fatty acid has a long and unbranched ____ chain.

A

carbon chain

or hydrocarbon chain

this accounts for the lipids’ insolubility in water

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3
Q

A fatty acid has a ____ group at one end that is usually ionized and accounts for the hydrophilic nature of the molecule

A

carboxyl group

ionized = COO-

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4
Q

In the notation 16:1 of Palmitoleic acid, what does 16 and 1 signify?

A
  • 16 = # of carbons
  • 1 = # of double bonds

kapag may triangle: ex: 16:1∆9, the 9 tells us that the double bond is found at the 9th carbon starting from the carboxyl end of the molecule

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5
Q

Characteristics of fatty acids

Nearly all fatty acids have an ____ number of carbon atoms, most between 12 and 20, in an unbranched chain.

odd or even

A

even

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6
Q

Characteristics of fatty acids

What are the three most abundant fatty acids in nature?

A
  • palmitic acid
  • stearic acid
  • oleic acid

16:0; 18:0; 18:1

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7
Q

Characteristics of fatty acids

In most unsaturated fatty acids, what isomer predominates?

A

cis isomer

trans is rare

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8
Q

Characteristics of fatty acids

Unsaturated fatty acids have ____ melting points than their saturated counterparts

higher or lower

A

lower

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9
Q

Characteristics of fatty acids

The ____ the degree of unsaturation, the lower the melting point

greater or lower

A

greater

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10
Q

What type of fatty acids only have single bonds in their hydrocarbon chains?

A

Saturated fatty acids

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11
Q

What type of fatty acids have double bonds in their hydrocarbon chains?

A

Unsaturated fatty acids

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12
Q

Saturated fatty acids are ____ at room temperature

solid or liquid

A

solid

because the regular nature of their hydrocarbon chains allows their molecules to pack together in a close parallel alignment

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13
Q

Unsaturated fatty acids are ____ at room temperature

solid or liquid

A

liquid

because the C=C double bonds create bends in the carbon chain, making it harder for fatty acids to pack together tightly.

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14
Q

True or False

The longer the hydrocarbon chain is, the more energy the energy is needed to separate and melt them

A

True

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15
Q

True or False

The double bonds present in unsaturated fatty acids inserts a bend in the hydrocarbon chain

A

True

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16
Q

Plant oils are liquid at room temperature because they have higher proportions of ____ fatty acids than do animal fats, which tend to be solids

saturated or unsaturated

A

unsaturated fatty acids

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17
Q

____ are triesters of glycerol and fatty acids.

A

Triglycerides

ester = R-O-(C=O)-R

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18
Q

What do you call the alcohol portion of triglycerides?

A

glycerol

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19
Q

What is the acid component of triglycerides?

A

fatty acids

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20
Q

Are triglycerides soluble in water or no?

A

no.

Although the ester groups are polar, they are buried in a nonpolar environment (hydrocarbon chains), that’s why they’re nonpolar & hydrophobic

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21
Q

What do you call the mixture of triglycerides containing high proportion of saturated fatty acids?

A

fats

properties of fatty acids are carried over to triglycerides

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22
Q

What do you call the mixture of triglycerides containing high proportion of unsaturated fatty acids and short-chain saturated fatty acids?

A

oils

properties of fatty acids are carried over to triglycerides

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23
Q

What are the two classifications of complex lipids?

A
  • phospholipids
  • glycolipids
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24
Q

What type of complex lipid contains an alcohol, two fatty acids, and a phosphate group?

A

Phospholipids

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25
Q

What type of complex lipid contains carbohydrates?

A

Glycolipids

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26
Q

What are the two types of phospholipids?

A
  • glycerophospholipids
  • sphingolipids

in glycerophospholipids, the backbone is glycerol; in sphingolipids, backbone is sphingosine

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27
Q

The lipid bilayer contains ____ fatty acids that accounts for the membrane’s fluidity

A

unsaturated fatty acids

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28
Q

What do you call the reaction of a triacylglycerol with a base producing glycerol and three molecules of fatty acids?

A

saponification

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29
Q

What do you call the type of phospholipid with a glycerol backbone, 2 fatty acids, and a phosphate group esterified to another alcohol?

A

glycerophospholipid

or phosphoacylglycerol

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30
Q

In the event that the alcohol to the phosphate group of the glycerophospholipid is esterified to a choline, what do you now call the compound?

A

phosphatidylcholine

or lecithin

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31
Q

In the event that the alcohol to the phosphate group of the glycerophospholipid is esterified to a ethanolamine or serine, what do you now call the compound?

A

phosphatidylethanolamine

or cephalin

abundant in egg yolk, wheat germ, yeast

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32
Q

In the event that the alcohol to the phosphate group of the glycerophospholipid is phosphate-esterified to inositol, what do you now call the compound?

A

phosphatidylinositol

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33
Q

what do you call the most abundant lipid in most cell membranes that has a polar head and two nonpolar tails?

A

phospholipids

phosphoacylglycerol

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34
Q

What do you call the type of phospholipids that have a sphingosine backbone?

A

sphingolipids

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35
Q

What do you call the bond between a fatty acid and a sphingosine?

A

ceramide

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36
Q

What types of lipids are the most important lipids in myelin sheaths of nerve cells and associated in diseases such as multiple sclerosis?

A

sphingomyelins

37
Q

What do you call the lipids that contain 3 cyclohexane rings and 1 cyclopentane rings fused together?

A

steroids

38
Q

What is the most abundant and most important steroid in the human body?

A

cholesterol

39
Q

What do you call the spherically-shaped molecules that transports cholesterol and fat?

A

Lipoproteins

40
Q

What are the 4 types of lipoproteins?

A
  • HDL
  • LDL
  • VLDL
  • Chylomicrons
41
Q

What steroid is considered as the precursor for the synthesis of other steroids and is derived from squalene?

A

Cholesterol

42
Q

Most cholesterol is transported in the body by what type of lipoproteins?

A

LDL

43
Q

What do you call the group of signal lipids that are derived from the metabolism of arachidonic acid by cyclooxygenase?

A

eicosanoids

44
Q

Identify the type of eicosanoids

  • stimulates muscle contraction
  • anticoagulant
  • controls blood pressure
  • stimulates muscle contraction
  • from prostanoic acid
A

Prostaglandins

45
Q

Identify the type of eicosanoids

  • induces platelet aggregation
  • induces vasoconstriction
A

Thromboxanes

46
Q

Identify the type of eicosanoids

  • produces muscle contractions, especially in the lungs
  • occurs mainly in leukocytes
  • drugs inhibit the synthesis of this eicosanoid (in asthma)
A

Leukotrienes

47
Q

Identify the fat-soluble vitamin

  • Isoprenoid alcohol that play a key role in visio
  • can be biosynthesized from B-carotene
A

Vitamin A

Retinoic Acid

48
Q

Identify the fat-soluble vitamin

  • Essential for bone health
  • Deficiency leads to bone defects
A

Vitamin D

Cholecalciferol

49
Q

Identify the fat-soluble vitamin

  • powerful antioxidant
  • important for skin health
A

Vitamin E

Alpha-Tocopherol

50
Q

Identify the fat-soluble vitamin

  • Important in the synthesis of prothrombin and protein factors in platelets
  • Deficiency leads to diminished intestinal absorption of lipids
A

Vitamin K

phylloquinone’ menaquinone

51
Q

What are the three reagents involved in the isolation of lipids from eggs?

A
  • Ethanol
  • Hexane
  • Acetone
52
Q

What reagent from the isolation process denatures the proteins and disrupts the lipoprotein complexes of egg yolk?

A

Ethanol

53
Q

What reagent from the isolation process was used to remove neutral or least polar lipids?

A

Hexane

54
Q

What reagent from the isolation process was used to provides a mild dehydration condition wherein:

  • H2O content decreases; thus, lipids are extracted
  • polar lipid w/ neutral lipids will further precipitate
A

Acetone

55
Q

Column chromatography is based on what principle wherein a solid holds molecules of a gas or liquid or solute as a thin film?

A

Adsorption

56
Q

What are the reagents used in column chromatography?

A
  • Petroleum ether:ethyl ether (9:1)
  • 5% MetOH in DCM
  • DCM:MetOH:H2O (1:3:1)

arranged from least polar to most polar*

57
Q

Stationary phase in TLC of lipids?

A

SIlica gel

58
Q

Identify the visualizing agent in TLC of lipids

  • appears as yellow-brown spots
  • oxidation of unsaturated fatty acids is involved as a rxn
A

I2

iodine

59
Q

Identify the visualizing agent in TLC of lipids

  • appears as blue-violet spots
  • detected in here are the free amino acid grps
A

Ninhydrin

60
Q

What are the standards used in TLC of lipids?

A
  • Cholesterol
  • Lecithin
61
Q

Identify the test based on reagents

  • ethanol:butanol (3:1)
  • NH2OH-HCl
  • NaOH
  • FeCl3
  • HCl
A

Hydroxamic test

62
Q

Identify the test based on reagents

  • KHSO4
  • Water bath
A

Acrolein test

63
Q

Identify the test based on reagents

  • conc. H2SO4
  • acetic anhydride
A

Liebermann-Burchard test

64
Q

Identify the test based on reagents

  • Bismuth nitrate
  • 3M HNO3
  • KI
A

Kraut’s test

65
Q

Identify the test based on reagents

  • 6M HNO3
  • 6M NaOH
  • Molybdate rgt
  • Ascorbic acid
A

Ascorbic Acid method

Test for Phosphate

66
Q

Identify the test based on reagents

  • triketohydrindene hydrate (ninhydrin in EtOH)
A

Ninhydrin test

67
Q

Identify the test based on reagents

  • 5% Bromine/Iodine solution
A

Test for lipid unsaturation

68
Q

Identify the test based on reagents

  • 1% ethanolic a-naphthol
  • conc. H2SO4
A

Molisch test

69
Q

Identify the test based on principle and purpose

  • complexation rxn
  • detects presence of carboxylic acid esters
  • detects TAGs, glycerophospholipids, cholesteryl esters
A

Hydroxamic test

test for ester

70
Q

Identify the test based on principle and purpose

  • dehydration and oxidation
  • detects glycerol
  • detects TAGs, glycerophospholipids
A

Acrolein test

test for glycerol

71
Q

Identify the test based on principle and purpose

  • esterification with acetic anhydride & epimerization of double bond at C5
  • detects presence of unsaturated sterols
  • detects cholesterol
A

Libermann-Burchard test

test for cholesterol

72
Q

Identify the test based on principle and purpose

  • complexation rxn
  • detects presence of choline
A

Kraut’s test

73
Q

Identify the test based on principle and purpose

  • reagents react in acidic medium with orthophosphate to form an acid that’ll be reduced later by ascorbic acid
  • detects phosphate
A

Test for Phosphate

Ascorbic acid method

74
Q

Identify the test based on principle and purpose

  • oxidative deamination followed by condensation
  • detects presence of a-amino grp
A

Ninhydrin test

75
Q

Identify the test based on principle and purpose

  • addition reaction
  • detects presence of double bonds (degree of unsaturation)
A

Test for Lipid Unsaturation

76
Q

Identify the positive result of the test

Hydroxamic test

Test for ester

A

burgundy color

77
Q

Identify the positive result of the test

Acrolein test

Test for glycerol

A

burnt fat odor

78
Q

Identify the positive result of the test

Libermann-Burchard test

Test for cholesterol

A

emerald green solution

79
Q

Identify the test based on principle and purpose

Kraut’s test

A

dark orange to red ppt

80
Q

Identify the test based on principle and purpose

Test for phosphate

Ascorbic acid method

A

molybdenum blue solution

or cerulean

81
Q

Identify the test based on principle and purpose

Test for Lipid Unsaturation

A

reddish brown color or violet coloration

82
Q

What is the identity of the first eluate in the column chromatography?

A
  • Triglycerides
  • Cholesteryl ester

i2 mga most nonpolar

83
Q

What is the identity of the second eluate in the column chromatography?

A

cholesterol

84
Q

What is the identity of the third eluate in column chromatography?

A
  • Glycerophospholipids
  • Sphingomyelin

most polar

85
Q

Which tests will be positive for triacylglycerides?

A
  • Hydroxamic test
  • Acrolein
  • Test for unsaturation (depende sa fatty acid chain)
86
Q

Which tests will be positive for cholesteryl esters?

A
  • Hydroxamic test
  • Liebermann-Burchard test
87
Q

Which tests will be positive for glycerophospholipids?

A
  • Hydroxamic
  • Acrolein
  • Kraut’s (phosphatidylcholine)
  • Test for unsaturation (depende ulet sa fatty acid chain)
  • Ninhydrin (for Phosphatidylenolamine)
88
Q

Which tests will be positive for sphingomyelin?

A
  • Kraut’s
  • Test for unsaturation (depende sa fatty acid chain)