Chapter 21 Lipids
Multiple Choice
1. Which saturated fatty acids have the correct name? (Sec. 21.2)
I) CH3(CH2)10COOH – stearic acid
II) CH3(CH2)14COOH – palmitic acid
III) CH3(CH2)16COOH – lauric acid
IV) CH3(CH2)18COOH – arachidic acid
a)
b)
c)
d)
I, II
III, IV
I, III
II, IV
2. Which properties are characteristic of the most abundant fatty acids found in plants and animals? (Sec. 21.2)
I) They contain an even number of carbon atoms, in the range 10-20.
II) The cis isomer predominates.
III) The unsaturated fatty acids have higher melting points than the corresponding saturated acids.
IV) The most abundant fatty acids are lauric, myristic and linolenic.
a)
b)
c)
d)
I, II
III, IV
I, III
II, IV
3. Which physical property of triacylglycerols rich in saturated fatty acids is responsible for the higher melting point
than the corresponding unsaturated compounds? (Sec. 21.2)
a)
b)
c)
d)
Dispersion forces
Hydrophilic interactions
Cis-carbon-carbon double bond steric interactions
Hydrogen bonding
4. Which physical property of triacylglycerols rich in unsaturated fatty acids is responsible for the lower melting
point than the corresponding saturated compounds? (Sec. 21.2)
a)
b)
c)
d)
Van der Waals attractions
Hydrophilic interactions
Cis-carbon-carbon double bond steric interactions
Hydrogen bonding
5. Deposits and films are a problem with soaps but not detergents because of which property? (Sec. 21.3)
a)
b)
c)
d)
Soaps form soluble calcium salts.
Detergents form more stable micelles.
Detergents do not form insoluble calcium salts.
Soap micelles are unstable in acid.
6. How many triglycerides, including stereoisomers, are possible if two fatty acids are present in the triglyceride?
(Sec. 21.2)
a)
b)
c)
d)
3
4
5
6
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Chapter 21 Lipids
7. Which natural products have structures derived from cholesterol? (Sec. 21.5, 21.7)
I) vitamin A
II) vitamin D
III) cholic acid
IV) cortisone
V) squalene
a)
b)
c)
d)
I, II, III
II, III, IV
III, IV, V
I, III, V
8. Which is not a characteristic group in phospholipids? (Sec. 21.4)
a)
b)
c)
d)
phosphate esters
fatty acid esters
glycerides
polyamides
9. Which property of phospholipids accounts for their ability to form micelles? (Sec. 21.4)
a)
b)
c)
d)
nonpolarity
unsaturation
hydrophilicity and lipophilicity
lipophilicity
10. Which property of phospholipids accounts for their ability to form fluid membranes? (Sec. 21.4)
a)
b)
c)
d)
nonpolarity
unsaturation
hydrophilicity and lipophilicity
lipophilicity
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Chapter 21 Lipids
11. Which is the structure of a phosphatidyl choline? (Sec. 21.4)
O
H2C O O
O
a)
H2NCH2CH2
O
(CH2 )16CH3
O
(CH2 )14CH3
HC O
H2C O O
P O CH2
O
HC O
+ COO
c) NH3 CH CH2 O P O CH2
O
(CH2 )16CH3
(CH2 )14CH3
O
O
H2C O O
+
b) (CH3 )3NCH2CH2
O
O
HC O
(CH2 )16CH3
(CH2 )14CH3
O
P O CH2
O
H2C O O
OH
O
HO
HO
d)
O
HO
OH
HC O
(CH2 )16CH3
(CH2 )14CH3
P O CH2
O
12. The fluid-mosaic model of the lipid bilayer states; (Sec. 21.4)
a) lipids coexist side by side as discreet units and proteins float in the bilayer, able to move along the plane
of the membrane.
b) the lipids form new covalent bonds between chains and lock the proteins into position, much like a
mosaic tile.
c) the lipids form a fluid-like membrane that metabolic components (the mosaic) can freely cross.
d) the lipid bilayer forms a rigid structure with channels that allow fluid to pass.
13. Which are the most common fatty acids found in phospholipids? (Sec. 21.4)
a)
b)
c)
d)
palmioleic, stearic, lauric
lauric, myristic, palmitic
palmitic, stearic, oleic
stearic arachidic, oleic
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Chapter 21 Lipids
14. Which is the number of stereocenters in methandrostenolone? (Sec. 21.5)
OH
CH3
CH3
CH3
H
H
O
a)
b)
c)
d)
4
6
8
10
15. Which reagents could be used to harden an oil to a fat? (Sec. 21.3)
a)
b)
c)
d)
NaBH4 / H2O
Ni / H2
Ag(NH3)2+ / H2O
Cu2+ / buffer
16. Which common structural feature of vitamin E and vitamin K 1 best accounts for the greater solubility of these
molecules in organic solvent than water? (Sec. 21.7)
O
CH3
O
CH3
vitamin K1
HO
H3C
O
CH3
CH3
vitamin E
a)
b)
c)
d)
aromatic rings
oxygen atoms
4 isoprene units
a quinone / hydroquinone units
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Chapter 21 Lipids
17. Which is a prostaglandin? (Sec. 21.6)
CH3
CH3
CH3
HO
CH2OH
a)
COOH
b)
CH3
CH3
HO
HO
H
O
CCH2OH
CH3
OH
HO
CH3
c)
H
H
H
d)
O
HO
18. Which structure is vitamin A? (Sec. 21.7)
CH3
CH3
CH3
HO
CH2OH
a)
COOH
b)
CH3
CH3
HO
HO
O
CCH2OH
CH3
OH
HO
CH3
c)
H
H
H
d)
O
HO
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H
Chapter 21 Lipids
19. Which structure is a cortisone? (Sec. 21.5)
CH3
CH3
CH3
HO
CH2OH
a)
COOH
b)
CH3
CH3
HO
HO
H
O
CCH2OH
CH3
OH
HO
CH3
c)
H
H
H
d)
O
HO
20. Fats, oils, phospholipids, prostaglandins and steroids have which properties in common? (Sec. 21.1)
I) oxygen functionality
II) nonpolar groups
III) rings
IV) unsaturation
a)
b)
c)
d)
I, II
III, IV
I, III
II, IV
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Chapter 21 Lipids
21. Which is the best description of the first step (A) of the biosynthesis of prostaglandin? (Sec. 21.6)
COOH
A
O
COOH
O
OOH
a)
b)
c)
d)
hydration
reduction
oxidation
Claisen condensation
22. Which is the best description of the second step (B) of the biosynthesis of prostaglandins? (Sec. 21.6)
O
COOH
O
OOH
B
O
COOH
O
OH
a)
b)
c)
d)
hydration
reduction
oxidation
Claisen condensation
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Chapter 21 Lipids
23. Which statements about steroids are false? (Sec. 21.5)
I) The fusion of all rings is cis.
II) Sex hormones, adrenocorticoid hormones, bile acids and vitamin D are derived from
cholesterol.
III) The biosynthesis of cholesterol produces several isomers.
IV) Steroids are tetracyclic ring systems
a)
b)
c)
d)
I, III
II, IV
I, II
III, IV
24. Which statements about vitamins are true? (Sec. 21.7)
I) Vitamins A, D, E and K are fat soluble.
II) Vitamins A, D, E and K are derived from cholesterol.
III) Vitamins A, D, E and K each contain 4 isoprene units.
IV) Vitamins A, D, E and K have distinct physiological activities.
a)
b)
c)
d)
II, III
III, IV
I, III
I, IV
25. The key step in the preparation of soap, saponification, is best described by which mechanism? (Sec. 21.3)
a)
b)
c)
d)
base catalyzed acyl addition
electrophilic addition
acid catalyzed acyl substitution
base catalyzed acyl substitution
Fill in the Blank
1. The melting point order of the following fatty acids is (lowest to highest),
lauric (12:0)
_______
palmitic (16:0)
_______
palmitoleic (16:1)
_______
oleic (18:1)
______
(Sec. 21.2)
2. The lower melting point of unsaturated fatty acids compared to saturated fatty acids is due to
______________________________ differences. (Sec. 21.2)
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Chapter 21 Lipids
3. Complete the reaction below by providing the missing products. (Sec. 21.3)
O
H2C O O
3NaOH, H2O
(CH2 )7 C C
H H
HC O
H2C
(CH2 )14CH3
O
H2C OH
HC OH
(CH2 )7CH3
H2C
(CH2 )16CH3
+
OH
O
4. Complete the structure of the alkylbenzene sulfonate detergent below. (Sec. 21.3)
CH3 (CH2 )12CH2
5. Complete the structure of the phospholipid below. (Sec. 21.4)
O
H2C O O
O
HC O
(CH2)16CH3
(CH2)14CH3
P O CH2
O
6. The forces which drive bilayer formation by phospholipids are __________________ and ________________.
(Sec. 21.4)
7. Androsterone has ________ stereocenters and ____________ possible stereoisomers. (Sec. 21.5)
CH3 O
CH3
H
H
H
HO
8. Vitamin A precursor -carotene belongs to the _____________ class of compounds and contains ________
isoprene units. (Sec. 21.7)
9. Prostaglandin is a member of the _________________ class of compounds, which are synthesized from
____________________. (Sec. 21.6)
10. Vitamins A, D, E, and K are included in the lipid class because they are _______ soluble. (Sec. 21.7)
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Chapter 21 Lipids
True-False
1. Stearic acid is an unsaturated fatty acid. (Sec. 21.2)
2. Human fat has more unsaturated fatty acids than plant fats. (Sec. 21.2)
3. Soaps and detergents form micelles when added to water. (Sec. 21.3)
4. Soap micelles form in water by aggregating the negatively charged carboxylate groups toward the inside and the
lipophilic carbon chains toward the outside of the micelle. (Sec. 21.3)
5. The forces that drive micelle and lipid bilayer formation are the same. (Sec. 21.4)
6. There are several stereoisomers of cholesterol found in living systems. (Sec. 21.5)
7. Aldosterone is an androgen. (Sec. 21.5)
8. Vitamin D precursors have the cholesterol ring system. (Sec. 21.7)
9. Vitamin E is required for blood clotting. (Sec. 21.7)
10. Prostaglandins are involved with the inflammatory response. (Sec. 21.6)
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Chapter 21 Lipids
Answers
Multiple Choice
1. d
2. a
3. a
4. c
5. c
6. d
7. b
8. d
9. c
10. c
11. b
12. a
13. c
14. b
15. b
16. c
17. b
18. a
19. c
20. a
21. c
22. b
23. a
24. d
25. d
Fill in the Blank
1. 3, 4, 1, 2
2. Conformational
3.
O
-O
(CH2 )14CH3
O
-O
(CH2 )7 C C
H H
-O
(CH2 )16CH3
(CH2 )7CH3
O
4.
CH3 (CH2 )12CH2
_
SO3
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Chapter 21 Lipids
5.
O
(CH2)16CH3
H2C O O
O
H2NCH2CH2O
(CH2)14CH3
HC O
P O CH2
O
O
or
H2C O O
O
(CH3)3NCH2CH2O
(CH2)16CH3
(CH2)14CH3
HC O
P O CH2
O
O
or
H2C O O
_
O
OOC
C C O
+ NH3 H H2
(CH2)16CH3
(CH2)14CH3
HC O
P O CH2
O
O
or
H2C O O
OH
HO
HO
OH
O
OH
O
(CH2)14CH3
HC O
P O CH2
O
6. hydrophobic and electrostatic
7. 7, 128
8. terpene, 8
9. eicosanoid, arachidonic acid
10. fat or low polarity organic
True-False
1.
2.
3.
4.
(CH2)16CH3
F
F
T
F
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Chapter 21 Lipids
5. T
6. F
7. F
8. T
9. F
10. T
270