Deck 23: Lipids

Question 1

Of the saturated fatty acids found in fats and oils,this one normally is the most abundant:

A) Capric acid
B) Lauric acid
C) Myristic acid
D) Palmitic acid
E) Stearic acid

Answer 1

Palmitic acid

Question 2

Which of these reagents would not react with stearic acid?

A) H₂,Ni
B) SOCl₂
C) CH₃MgI
D) NH₃/H₂O
E) LAH

Answer 2

H₂,Ni

Question 3

Which is an untrue statement concerning the fatty acid moieties of naturally-occurring triacylglycerols?

A) Generally,they possess an even number of carbon atoms.
B) Most have unbranched carbon chains.
C) The double bonds,when present,all are in the cis configuration.
D) Where two or three double bonds are present in the same fatty acid moiety,they comprise a conjugated system.
E) The fatty acid moieties in a particular triacylglycerol usually are different.

Answer 3

Where two or three double bonds are present in the same fatty acid moiety,they comprise a conjugated system.

Question 4

Which of these reagents would not react with oleic acid?

A) H₂,Ni
B) PBr₃
C) CH₃MgI
D) NH₃/H₂O
E) NaBH₄

Question 5

Which of the following statements regarding triacylglycerols is not true?

A) They are synthesized in the body by adipocytes.
B) They have an odd number of carbon atoms.
C) They are solid if they do not have alkene bonds.
D) Those which can be hydrogenated,undergo a significant change in melting point upon hydrogenation.
E) They can be hydrolyzed to give glycerol and fatty acids.

Question 6

Which fatty acid is likely to occur commonly in natural sources?

A) II
B) I and IV
C) II and III
D) II,III and IV
E) V

Question 7

Which of the following might be helpful in distinguishing between oleic acid and linoleic acid?

A) Examine the stoichiometry of the reaction with NaOH/H₂O
B) Examine the stoichiometry of complete catalytic hydrogenation.
C) Examine products obtained after subjecting the sample to catalytic hydrogenation
D) Examine products obtained after subjecting the sample to : i)O₃,CH₂Cl₂;ii)Zn,CH₃CO₂H
E) Two of the above

Question 8

Consider a micelle composed of phosphatidyl choline,shown below.Which part(s)of the molecule would form the hydrophilic surface of the micelle?

A) 3
B) 2
C) 1
D) 1 and 2
E) 2 and 3

Question 9

Which of these is a detergent?

A) CH₃(CH₂)₁₆COO^-Na⁺
B) [CH₃(CH₂)₁₄COO^-]₂Ca⁺²
C) CH₃(CH₂)₁₀CH₂SO₃^-Na⁺
D) HOCH₂CHOHCH₂OH
E) CH₃(CH₂)₁₄CH₂SH

Question 10

Which of these reagents would not react with oleic acid?

A) H₂,Ni
B) DIBAL-H
C) O₃/CH₂Cl₂
D) NH₃/H₂O
E) LAH

Question 11

Which fatty acid is not likely to occur commonly in natural sources?

A) (Z)- 11-Tetradecenoic acid
B) (Z)- 9-Pentadecenoic acid
C) Hexadecanoic acid
D) (9Z,12Z)- 9,12-octadecadienoic acid
E) (Z)-9-hexadecenoic acid

Question 12

Which fatty acid is not likely to occur commonly in natural sources?

A) Tetradecanoic acid
B) Pentadecanoic acid
C) Hexadecanoic acid
D) (9Z,12Z)-octadeca-9,12-dienoic acid
E) (Z)-hexadeca-9-enoic acid

Question 13

Which fatty acid is not likely to occur commonly in natural sources?

A) CH₃(CH₂)₁₂COOH
B) CH₃(CH₂)₁₄COOH
C)

D)

E)

Question 14

Which of the following would serve as the basis for a simple chemical test that would distinguish between stearic acid and oleic acid?

A) NaOH/H₂O
B) NaHCO₃/H₂O
C) HCl/H₂O
D) Ag(NH₃)₂⁺
E) Br₂/CCl₄

Question 15

How could you synthesize stearolic acid,CH₃(CH₂)₇C $\equiv$ C(CH₂)₇COOH from oleic acid,CH₃(CH₂)₇CH=CH(CH₂)₇COOH?

A) Br₂,CCl₄;then 3 Na,NH₃,heat;then H₃O⁺
B) Li,liq.NH₃;then H₃O⁺
C) H₂,Pd
D) Peracid;then H₃O⁺;then HA,H₂O,heat
E) excess HCl;then KOH,C₂H₅OH,heat

Question 16

Which of the following statements regarding triacylglycerols is not true?

A) They undergo alkaline hydrolysis to yield soaps.
B) They are liquid if they have alkene bonds.
C) They are solid if they do not have alkene bonds.
D) Some can be hydrogenated.
E) They are soluble in water.

Question 17

How could you convert an unsaturated fatty acid into a saturated fatty acid?

A) KMnO₄,OH^-,heat
B) OH^-,H₂O,heat;then H₃O⁺
C) H₂,Ni,pressure
D) H₃O⁺,H₂O,heat
E) O₃;then Zn,HOAc

Question 18

Which of the following statements regarding triacylglycerols is true?

A) They form micelles when mixed with water.
B) They are liquid if they are unsaturated.
C) They are solid if they have alkyne bonds.
D) They can be used to wash dirty dishes
E) They are soluble in water.

Question 19

Which is not a correct statement concerning naturally-occurring triacylglycerols?

A) The greater the degree of unsaturation,the higher the melting point.
B) Saponification yields glycerol and a mixture of carboxylic acid salts.
C) Solid examples are termed "fats."
D) Regardless of the exact nature of the R groups,such compounds are water-insoluble.
E) Such compounds frequently,but less correctly,are called "triglycerides."

Question 20

Which of the following statements regarding triacylglycerols is not true?

A) Some undergo autooxidation with oxygen from air.
B) They are solid if they do not have alkene bonds.
C) They form lipid bilayers.
D) They form micelles in water.
E) Two of the above are false statements.

Question 21

The final product of the following reaction sequence would be:,

A) I
B) II
C) III
D) IV
E) V

Question 22

Which of the following compounds would be most likely to be found in nature? (Hint: recall the isoprene rule. )

A) I
B) II
C) III
D) IV
E) V

Question 23

The product of the following reaction sequence is nervonic acid.What is the structure of nervonic acid?

A)

B)

C)

D)

E)

Question 24

Which compound below does not obey the isoprene rule?

A) I
B) II
C) III
D) IV
E) V

Question 25

In the vulcanization of rubber,

A) natural rubber is heated with sulfur.
B) reaction occurs at allylic positions.
C) cross-linking results in a hardening of the rubber.
D) disulfide bridges are formed.
E) All of the above

Question 26

Which is the repeating unit of natural rubber?

A) I
B) II
C) III
D) IV
E) V

Question 27

In $\beta$ -carotene,how many tail-to-tail links of isoprene units are there?

A) 1
B) 2
C) 3
D) 4
E) More than 4

Question 28

The ozonolysis of a fatty acid produces these fragments: What is the identity of the fatty acid?

A) Stearic acid
B) Palmitoleic acid
C) Oleic acid
D) Linoleic acid
E) Linolenic acid

Question 29

What would be the product,X,of the following reaction sequence?

A)

B)

C) CH₃(CH₂)₁₁CH₂NH₂
D) CH₃(CH₂)₁₂CONH₂
E) CH₃(CH₂)₁₂COBr

Question 30

To which class of terpenes does the terpene shown below,bisabolene,belong?

A) Monoterpenes
B) Sesquiterpenes
C) Diterpenes
D) Triterpenes
E) Tetraterpenes

Question 31

How many isomers,including stereoisomers,exist for the triacylglycerol which,on saponification,gives 2 molar equivalents of palmitate and 1 molar equivalent of stearate?

A) 1
B) 2
C) 3
D) 4
E) 6

Question 32

Which compound is a sesquiterpene?

A) I
B) II
C) III
D) IV
E) V

Question 33

How many isoprene units are in vitamin A?

A) 1
B) 2
C) 3
D) 4
E) More than 4

Question 34

What would be the product of the following reaction sequence?

A) CH₃(CH₂)₅CH=CH(CH₂)₁₄CH₃
B) CH₃(CH₂)₅COOCH₂(CH₂)₁₄CH₃ and CH₃(CH₂)₅CH=CH(CH₂)₇COOCH₂(CH₂)₁₄CH₃
C) CH₃(CH₂)₁₄COOCH₂(CH₂)₁₄CH₃
D) CH₃(CH₂)₁₃CHClCOOCH₂(CH₂)₁₄CH₃
E) CH₃(CH₂)₅CH=CH(CH₂)₇COOCH₂(CH₂)₁₄CH₃

Question 35

Which structure represents a terpene likely to be found in nature?

A) I
B) II
C) III
D) IV
E) V

Question 36

Which fatty acid is responsible for the putrid odor of rancid butter?

A) Valeric acid
B) Myristic acid
C) Stearic acid
D) Oleic acid
E) Butyric acid

Question 37

Which reagent might be used to convert 5 $\infty$ -cholest-1-en-3-ol into 5 $\infty$ -cholestan-3-ol?

A) CrO₃/pyridine
B) KMnO₄/H₂O
C) CH₃MgI
D) H₂/Pt
E) Li/C₂H₅NH₂

Question 38

Which of the following statements regarding lipids is not true?

A) Lipids are soluble in non-polar organic solvents.
B) All lipids have the same functional groups.
C) Lipids include waxes,steroids,and triacylglycerols.
D) Lipids have little in common except their solubility.
E) Many lipids have biological roles.

Question 39

Which is the proper representation of three successive isoprene units in natural rubber?

A) I
B) II
C) III
D) IV
E) V

Question 40

The product of the following reaction sequence may be described as?

A) Alkoxyalkane
B) Alkyl alkanoate
C) Alkyl alkenoate
D) Acyl glycerol
E) Acyl Alkane

Question 41

Which type of lipid gives these products on saponification: HOCH₂CHOHCH₂OH RCO₂¯ R'CO₂¯ PO₄³¯ HOCH₂CH₂NH₂ ?

A) Fat
B) Wax
C) Lecithin
D) Cephalin
E) Plasmalogen

Question 42

Which of the following characteristics are found in the class of C₂₀ carboxylic acids called prostaglandins?

A) a five membered ring
B) One or more double bonds
C) Several oxygen containing groups
D) Two of the above
E) All of the above

Question 43

The biosynthesis of one series of prostaglandins begins with which of these fatty acids?

A) Palmitic acid
B) Stearic acid
C) Oleic acid
D) Linoleic acid
E) Arachidonic acid

Question 44

Choline cannot be found as a product of hydrolysis of any representative of this class of lipids.

A) Cerebrosides
B) Phosphatidylserine
C) Plasmalogens
D) Waxes
E) None of the above yield choline upon hydrolysis

Question 45

The synthesis of cortisone required placing a ketone function at the 11-position of a steroid.Where is position 11?

A) I
B) II
C) III
D) IV
E) V

Question 46

Shown below is the formula for the antiinflammatory drug called prednisone.What is a correct systematic name for prednisone?

A) 17 $\infty$ ,21-Dihydroxypregna-1,4-diene-3,11,20-trione
B) 17 $\beta$ ,21-Dihydroxypregna-1,4-diene-3,11,20-trione
C) 17 $\infty$ ,19-Dihydroxypregna-1,4-diene-3,11,20-trione
D) 17 $\beta$ ,19-Dihydroxypregna-1,4-diene-3,11,20-trione
E) None of the above

Question 47

Which of these is a correct systematic name for progesterone?

A) 2-Estrene-4,20-dione
B) 5-Androstene-4,19-dione
C) 4-Pregnene-3,20-dione
D) 5-Cholestene-5,19-dione
E) 4-Cholene-3,20-dione

Question 48

How many stereogenic centers are there in cholesterol?

A) 2
B) 4
C) 6
D) 8
E) 16

Question 49

Which reagent might serve as the basis for a simple chemical test that would distinguish between 5 $\infty$ -cholest-1-en-3-one and 5 $\infty$ -cholestan-3-one?

A) Ag(NH₃)₂⁺
B) CrO₃/H₂SO₄
C) Br₂/CCl₄
D) NaOH/H₂O
E) C₆H₅NHNH₂

Question 50

The reaction of cholesterol with dilute aqueous KMnO₄ at 0-5°C produces which of these compounds (A and B rings only shown)?

A) I
B) II
C) III
D) IV
E) V

Question 51

Which of the following is a female sex hormone?

A) Ergosterol
B) Estradiol
C) Cortisone
D) Androsterone
E) Cholic acid

Question 52

Which of these lipids yields choline upon hydrolysis?

A) A lecithin
B) A sphingomyelin
C) A cephalin
D) A cerebroside
E) Two of the above

Question 53

Which type of lipid gives the following products on saponification? HOCH₂CHOHCH₂OH RCO₂¯ R'CO₂¯ PO₄³¯ [HOCH₂CH₂N(CH₃)₃]⁺OH ^-

A) Fat
B) Wax
C) Lecithin
D) Cephalin
E) Plasmalogen

Question 54

Which is an untrue statement concerning cholesterol?

A) Cholesterol decolorizes a solution of Br₂ in CCl₄.
B) Cholesterol reacts with 2,4-dinitrophenylhydrazine.
C) Cholesterol is optically active.
D) Cholesterol is water-insoluble.
E) All of the above are true.

Question 55

In the biosynthesis of vitamin D₂,which alkane bond of ergosterol is cleaved?

A) I
B) II
C) III
D) IV
E) V

Question 56

What product would be obtained by catalytic hydrogenation of 5-cholesten-3 $\beta$ -ol?

A) 5 $\beta$ -Cholestan-3 $\beta$ -ol
B) 5 $\infty$ -Cholestan-3 $\beta$ -ol
C) 5 $\infty$ -Cholestan-3 $\infty$ -ol
D) 5 $\beta$ -Cholestan-3 $\infty$ -ol
E) 5-Cholesten-3 $\beta$ ,6 $\infty$ -diol

Question 57

Which of the following is a phosphatidic acid?

A) I
B) II
C) III
D) IV
E) V

Question 58

Which of these is a male sex hormone?

A) Estrone
B) Testosterone
C) Cholic acid
D) Cortisone
E) Estradiol

Question 59

What product would you expect when progesterone is treated with one molar equivalent of hydrogen in the presence of a platinum catalyst?

A) 5 $\infty$ -Pregnane-3,20-dione
B) 5 $\beta$ -Pregnane-3,20-dione
C) 5 $\infty$ -Estrane-3,20-dione
D) 5 $\beta$ -Estrane-3,20-dione
E) 5 $\infty$ -Androstane-3,20-dione

Question 60

Which is the correct systematic name for the steroid shown below?

A) 5 $\infty$ -Androstan-3 $\infty$ -ol
B) 5 $\beta$ -Androstan-3 $\beta$ -ol
C) 5 $\beta$ -Androstan-3 $\infty$ -ol
D) 5 $\infty$ -Androstan-3 $\beta$ -ol
E) 5 $\beta$ -Estan-3 $\beta$ -ol

Question 61

Saturated fatty acids pack efficiently.Therefore the corresponding triacylglycerols tend to be __________ at room temperature and are called __________.

Question 62

Unlike carbohydrates and proteins,which are defined in terms of their structures,lipids are defined in terms of _____________.

Question 63

How could you synthesize stearolic acid,CH₃(CH₂)₇C≡C(CH₂)₇COOH from oleic acid,CH₃(CH₂)₇CH=CH(CH₂)₇COOH? Specify stoichiometric details,providing a brief explanation of your rationale.

Question 64

Salts of long-chain fatty acids are known as ___________.

Question 65

Which of these is most likely to have properties resembling natural waxes?

A) I
B) II
C) III
D) IV
E) V

Question 66

The characteristic odor of rancid butter is attributed to ___________.

Question 67

Unsaturated fatty acids have a bend in the carbon chain that interferes with packing.Therefore the corresponding triacylglycerols are generally __________ at room temperature and are called _______.

Question 68

In naturally occurring polyunsaturated fatty acids,the stereochemistry of the double bonds is rarely ___________.

Question 69

Explain how soap removes dirt from clothes.

Question 70

Suggest a reasonable synthetic strategy for the synthesis of N,N-dimethylstearamide ,CH₃(CH₂)₁₆CON(CH₃)₂ from oleic acid,cis 9-octadecenoic acid

Question 71

Draw the structure for the product of the reaction presented on the scheme.Name the process.

Question 72

Complete and name the process:

Question 73

In naturally occurring polyunsaturated fatty acids,the relative position of double bonds is rarely ___________.

Question 74

Which of these is a wax?

A)

B)

C)

D)

E) CH₃(CH₂)₂₄CH₂OH

Question 75

There is growing evidence that "trans" fats are associated with an increased risk of ___________,and the FDA now requires "trans fat" information to be provided on nutrition labels.

Question 76

Which of these lipids yields glycerol upon hydrolysis?

A) A lecithin
B) A phosphatidylserine
C) A cephalin
D) A triacylglycerol
E) All of the above

Question 77

Which of these lipids does not yield glycerol upon hydrolysis?

A) A lecithin
B) A sphingolipid
C) A cephalin
D) A triacylglycerol
E) A plasmalogen

Question 78

Olestra,a synthetic fat substitute,contributes nothing to the caloric value of foods prepared with it,because it passes through the body without being digested.Why are the lipases,responsible for facilitating normal fat hydrolysis,unable to facilitate the hydrolysis of olestra?

Question 79

Prolonged heating of naturally occurring polyunsaturated fats may cause the stereochemistry of the double bonds to change from ___________.

Question 80

The primary function of triacylglycerols (triglycerides)in animals is _____________.