1. Which Saturated Fatty Acids Have the Correct Name? (Sec. 21.2)
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) I, II
b) III, IV
c) I, III
d) 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) I, II
b) III, IV
c) I, III
d) 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) Dispersion forces
b) Hydrophilic interactions
c) Cis-carbon-carbon double bond steric interactions
d) 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) Van der Waals attractions
b) Hydrophilic interactions
c) Cis-carbon-carbon double bond steric interactions
d) Hydrogen bonding
5. Deposits and films are a problem with soaps but not detergents because of which property? (Sec. 21.3)
a) Soaps form soluble calcium salts.
b) Detergents form more stable micelles.
c) Detergents do not form insoluble calcium salts.
d) 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) 3
b) 4
c) 5
d) 6
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) I, II, III
b) II, III, IV
c) III, IV, V
d) I, III, V
8. Which is not a characteristic group in phospholipids? (Sec. 21.4)
a) phosphate esters
b) fatty acid esters
c) glycerides
d) polyamides
9. Which property of phospholipids accounts for their ability to form micelles? (Sec. 21.4)
a) nonpolarity
b) unsaturation
c) hydrophilicity and lipophilicity
d) lipophilicity
10. Which property of phospholipids accounts for their ability to form fluid membranes? (Sec. 21.4)
a) nonpolarity
b) unsaturation
c) hydrophilicity and lipophilicity
d) lipophilicity
11. Which is the structure of a phosphatidyl choline? (Sec. 21.4)
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) palmioleic, stearic, lauric
b) lauric, myristic, palmitic
c) palmitic, stearic, oleic
d) stearic arachidic, oleic
14. Which is the number of stereocenters in methandrostenolone? (Sec. 21.5)
a) 4
b) 6
c) 8
d) 10
15. Which reagents could be used to harden an oil to a fat? (Sec. 21.3)
a) NaBH4 / H2O
b) Ni / H2
c) Ag(NH3)2+ / H2O
d) Cu2+ / buffer
16. Which common structural feature of vitamin E and vitamin K1 best accounts for the greater solubility of these molecules in organic solvent than water? (Sec. 21.7)
a) aromatic rings
b) oxygen atoms
c) 4 isoprene units
d) a quinone / hydroquinone units
17. Which is a prostaglandin? (Sec. 21.6)
18. Which structure is vitamin A? (Sec. 21.7)
19. Which structure is a cortisone? (Sec. 21.5)
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) I, II
b) III, IV
c) I, III
d) II, IV
21. Which is the best description of the first step (A) of the biosynthesis of prostaglandin? (Sec. 21.6)
a) hydration
b) reduction
c) oxidation
d) Claisen condensation
22. Which is the best description of the second step (B) of the biosynthesis of prostaglandins? (Sec. 21.6)
a) hydration
b) reduction
c) oxidation
d) Claisen condensation
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) I, III
b) II, IV
c) I, II
d) 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) II, III
b) III, IV
c) I, III
d) I, IV
25. The key step in the preparation of soap, saponification, is best described by which mechanism? (Sec. 21.3)
a) base catalyzed acyl addition
b) electrophilic addition
c) acid catalyzed acyl substitution
d) 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)
3. Complete the reaction below by providing the missing products. (Sec. 21.3)
4. Complete the structure of the alkylbenzene sulfonate detergent below. (Sec. 21.3)
5. Complete the structure of the phospholipid below. (Sec. 21.4)
6. The forces which drive bilayer formation by phospholipids are ______and ______. (Sec. 21.4)
7. Androsterone has ______stereocenters and ______possible stereoisomers. (Sec. 21.5)
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)
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)
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.
4.
5.
6. hydrophobic and electrostatic
7. 7, 128
8. terpene, 8
9. eicosanoid, arachidonic acid
10. fat or low polarity organic
True-False
1. F
2. F
3. T
4. F
5. T
6. F
7. F
8. T
9. F
10. T
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