Chapter 17: Lipids and Their Functions in Biochemical
Systems
1. What is the common name for the fatty acid with the condensed structure shown below?
CH3(CH2)10COOH
A) lauric acid
B) oleic acid
C) capric acid
D) linoleic acid
E) arachidonic acid
Ans: A
2. Which statement concerning the structure of a fatty acid is FALSE?
A) Fatty acids are naturally occurring, long-chain carboxylic acids.
B) The carbon chain in a fatty acid may be branched or unbranched.
C) Fatty acids generally contain an even number of carbons.
D) The carbon chain in a fatty acid may be saturated or unsaturated.
E) When present in fatty acids, C=C bonds are usually cis.
Ans: B
3. Which of the following is NOT classified as a type of eicosanoid?
A) steroids
B) prostaglandins
C) thromboxanes
D) leukotrienes
E) All are considered eicosanoids.
Ans: A
4. What response is caused by the prostaglandins produced in the kidneys?
A) stimulation of ovulation
B) smooth muscle contractions
C) dilation of renal blood vessels
D) constriction of blood vessels and aggregation of platelets
E) water retention and weight gain
Ans: C
5. Which eicosanoids produced by white blood cells can cause bronchial constriction?
A) prostaglandins
B) fatty acids
C) bile salts
D) leukotrienes
E) steroids
Ans: D
Page 173
Chapter 17 Lipids and Their Functions in Biochemical Systems
6. Which statement best describes how lipids are defined?
A) Lipids are biomolecules that contain the ester functional group.
B) Lipids are biomolecules that contain fatty acids.
C) Lipids are biomolecules that have negative effects on a person’s health.
D) Lipids are biomolecules that are solids at room temperature.
E) Lipids are structurally diverse biomolecules that are soluble in nonpolar solvents and
insoluble in water.
Ans: E
7. The structure of a phosphoglyceride is shown below. Phosphoglycerides can interact
with both water and other lipids, and are therefore well suited for their role in the lipid
bilayer of cell membranes. Which of the following best explains this behavior?
A) Phosphoglycerides contain a phosphate diester.
B) Phosphoglycerides contain both hydrophobic and hydrophilic regions.
C) Phosphoglycerides contain saturated fatty acids as well as unsaturated fatty acids.
D) Phosphoglycerides contain both single bonds and double bonds between carbons.
E) Phosphoglycerides contain omega-3 and omega-6 fatty acids.
Ans: B
8. Which of the following statements concerning lipid functions is NOT true?
A) The human body uses triglycerides for long-term energy storage, insulation, and
protection.
B) Plants and animals use waxes as water barriers.
C) Phosphoglycerides are key components of the structure of cell membranes.
D) Steroids function as messenger molecules that enable cell-cell communication.
E) All statements concerning lipid functions are true.
Ans: E
9. What is the most abundant class of membrane lipids?
A) prostaglandins
B) triglycerides
C) waxes
D) phosphoglycerides
E) eicosanoids
Ans: D
Page 174
Chapter 17 Lipids and Their Functions in Biochemical Systems
10. What nitrogen-containing alcohol forms the backbone of the sphingolipids?
A) ethanolamine
B) ammonia
C) aniline
D) cortisol
E) sphingosine
Ans: E
11. Consider the compound represented below. Which of the following best describes it?
A) It is a nonpolar amino acid.
B) It is a triglyceride.
C) It is a soap.
D) It is an unsaturated fatty acid.
E) It is an omega-3 wax.
Ans: D
12. Cetyl palmitate is a component of spermaceti wax, isolated from the heads of sperm
whales, and used in cosmetics. In which solvent would cetyl palmitate be expected to
have the greatest solubility?
A) acetic acid (CH3COOH)
B) ethyl alcohol (CH3CH2OH)
C) petroleum ether (a mixture of liquid alkanes)
D) water
E) 5% NaCl(aq)
Ans: C
13. The ingredients on a box of cupcakes lists partially hydrogenated soybean oil. Partial
hydrogenation of soybean oil has what effect?
A) It produces fatty acid salts from the triglycerides that are present.
B) It decreases the percentage of unsaturation present in the fatty acid side chains.
C) It hydrolyzes the triglycerides that are present.
D) It increases the number of fatty acids present.
E) It converts the soybean oil to butter.
Ans: B
Page 175
Chapter 17 Lipids and Their Functions in Biochemical Systems
14. What two products are formed in the hydrolysis of a wax?
A) a long-chain alcohol and an ester
B) a fatty acid and an ester
C) a fatty acid and a long-chain alcohol
D) a triglyceride and a soap
E) an alcohol and a bile salt
Ans: C
15. Which class of human plasma lipoproteins carries triglycerides from the intestine to
other tissues?
A) chylomicrons
B) high density lipoproteins (HDL)
C) low density lipoproteins (LDL)
D) very low density lipoproteins (VLDL)
E) sphingomyelins
Ans: A
16. Which class of human plasma lipoproteins binds triglycerides synthesized in the liver
and carries them to adipose for storage?
A) chylomicrons
B) high density lipoproteins (HDL)
C) low density lipoproteins (LDL)
D) very low density lipoproteins (VLDL)
E) sphingomyelins
Ans: D
17. Which class of lipoprotein carries cholesterol to peripheral tissues and helps regulate
cholesterol levels in those tissues?
A) chylomicrons
B) high density lipoproteins (HDL)
C) low density lipoproteins (LDL)
D) very low density lipoproteins (VLDL)
E) sphingomyelins
Ans: C
18. Which class of lipoprotein is bound to plasma cholesterol and transports it from the
peripheral tissues to the liver?
A) chylomicrons
B) high density lipoproteins (HDL)
C) low density lipoproteins (LDL)
D) very low density lipoproteins (VLDL)
E) sphingomyelins
Ans: B
Page 176
Chapter 17 Lipids and Their Functions in Biochemical Systems
19. How can the structure and composition of biological membranes be best described?
A) lipid bilayer
B) protein micelle
C) hydrophilic barrier
D) emulsifying layer
E) saturated triglyceride
Ans: A
20. Testosterone, cholesterol, and progesterone are all classified as steroids because they
contain the steroid nucleus. Which of the following compounds would also be classified
as a steroid?
A) I only
B) II only
C) III only
D) I and II
E) I, II, and III
Ans: A
21. How does the proportion of saturation and unsaturation in membrane lipids affect the
fluidity of the cell membrane?
A) Membrane fluidity increases with an increase in the percentage of unsaturation.
B) Membrane fluidity decreases with an increase in the percentage of unsaturation.
C) Membrane fluidity increases with an increase in the percentage of saturation.
D) Membranes are most fluid when there is an equal proportion of saturation and
unsaturation.
E) Membrane fluidity depends only on the size of the carbon chains, and not on the
proportions of saturation and unsaturation.
Ans: A
Page 177
Chapter 17 Lipids and Their Functions in Biochemical Systems
22. A tube of lipstick lists capric triglyceride among its ingredients. Capric triglyceride is a
simple triglyceride containing capric acid, a 10-carbon saturated fatty acid. What is the
structure of capric triglyceride?
A)
B)
C)
D)
E)
Ans: B
Page 178
Chapter 17 Lipids and Their Functions in Biochemical Systems
23. Dietary fats and oils are structurally both triglycerides, but fats are solids and oils are
liquids at room temperature. Which of the following best describes the reason for their
difference in physical state?
A) Fats contain 3 identical fatty acid R groups and oils contain different R groups.
B) Oils contain 3 identical fatty acid R groups and fats contain different R groups.
C) Oils contain longer fatty acid R groups than fats do.
D) Fats contain more hydroxyl groups in their fatty acid R groups than oils do.
E) Oils contain a higher percentage of unsaturation in their fatty acid R groups than fats
do.
Ans: E
24. When three fatty acids react with glycerol, a lipid known as a triglyceride is formed.
How are the fatty acids bonded to glycerol?
A) by amide bonds
B) by ester bonds
C) by glycosidic linkages
D) by acetal bonds
E) by hydrogen bonding
Ans: B
25. When palmitic acid, a 16-carbon saturated fatty acid, reacts with a 30-carbon
unbranched alcohol, a wax is formed. What is the structure of this wax?
A)
B)
C)
D)
E)
Ans: D
Page 179
Chapter 17 Lipids and Their Functions in Biochemical Systems
26. What two products are formed in the reaction between a fatty acid and an alcohol?
A)
B)
C)
Ans:
ester and hydrogen
ester and water
ether and water
B
D)
E)
ether and hydrogen
hydrogen and alkane
27. What is the name of the product that results from the hydrogenation reaction below?
A)
B)
C)
Ans:
stearic acid
arachidic acid
palmitic acid
A
D)
E)
28. What two fatty acids are essential fatty acids?
A) palmitoleic acid and oleic acid
D)
B) linoleic acid and stearic acid
E)
C) arachidonic acid and eicosanoids
Ans: D
linoleic acid
capric acid
linolenic acid and linoleic acid
stearic acid and oleic acid
29. What products are formed from the complete hydrolysis of a triglyceride?
A) glycerol and 3 fatty acids
D) All of the choices are correct.
B) glycerol and 2 fatty acids
E) None of the choices are correct.
C) glycerol and 1 fatty acid
Ans: A
30. What is meant by the term “mixed” triglyceride?
A) It is a mixture of at least two different triglycerides.
B) It is the term used to describe the production of triglycerides.
C) It is a triglyceride containing different acyl groups.
D) It is the term for the digestion of triglycerides in the body.
E) It is a triglyceride in which all three acyl groups are identical.
Ans: C
31. Which lipid is found in egg yolks and soybeans and is used as an emulsifying agent in
ice cream?
A) sphingosine
D) lauric acid
B) linoleic acid
E) Both C and D are correct.
C) lecithin
Ans: C
Page 180
Chapter 17 Lipids and Their Functions in Biochemical Systems
32. What is the starting material for the synthesis of steroids in the body?
A) glucose B) testosterone C) stearic acid D) cholate E) cholesterol
Ans: E
33. Which of the following is a synthetic steroid hormone that can be taken orally for birth
control?
A) norlutin
D) stanozolol
B) albuterol
E) ibuprofen
C) testosterone
Ans: A
34. Saponification of the triglyceride shown below produces soap. What is the structure of
the soap?
A) Na+ −O(CH2)10CH3
B)
C)
D)
E)
Ans: C
35. What type of lipid is formed in the reaction between a long-chain alcohol and a fatty
acid?
A) triglyceride B) oil C) steroid D) cholesterol E) wax
Ans: E
36. Glycolipids contain what type of compound joined to the lipid portion of the molecule?
A) protein
B) enzyme
C) vitamin
D) carbohydrate
E) amino acid
Ans: D
Page 181
Chapter 17 Lipids and Their Functions in Biochemical Systems
37. Fatty acids generally contain how many carbon atoms?
A) 12 B) 8 C) 6 D) an odd number E) an even number
Ans: E
38. What type of fatty acid is represented by the formula CnH2nCOOH?
A) saturated fatty acid
B) unsaturated fatty acid
C) essential fatty acid
D) nonessential fatty acid
E) chiral fatty acid
Ans: B
39. What process converts an unsaturated fatty acid into a saturated fatty acid?
A) oxidation
B) combustion
C) substitution
D) hydrolysis
E) hydrogenation
Ans: E
40. What is the product of the complete hydrogenation of linoleic acid?
A) sodium linoleate
Ans: E
B) a diol
C) arachidonic acid
D) an ester E) stearic acid
41. What highly unsaturated fatty acid and precursor to many prostaglandins, is synthesized
from the fatty acid linoleic acid in the body?
A) oleic acid
D) arachidonic acid
B) linolenic acid
E) palmitoleic acid
C) stearic acid
Ans: D
42. Which of the following hormone-like molecules is NOT produced from arachidonic
acid?
A) prostaglandins
D) thromboxanes
B) eicosanoids
E) steroids
C) leukotrienes
Ans: E
Page 182
Chapter 17 Lipids and Their Functions in Biochemical Systems
43. Which kind of eicosanoids is thought to promote certain aspects of the inflammatory
response?
A) leukotrienes
D) steroids
B) prostaglandins
E) fatty acids
C) thromboxanes
Ans: B
44. Painful menstruation may be the result of an excess of which of the following
eicosanoids?
A) leukotrienes
D) steroids
B) thromboxanes
E) phospholipids
C) prostaglandins
Ans: C
45. Cyclooxygenase catalyzes the conversion of arachidonic acid into PGH2. What drug
inhibits this enzyme?
A) lactaid B) aspirin C) progesterone D) norlutin E) cortisone
Ans: B
46. What is the major energy storage form found in fat cells?
A) waxes
D) triglycerides
B) phospholipids
E) low density lipids
C) acetylcholines
Ans: D
47. What is the product that results upon complete hydrogenation of the fatty acid shown?
A)
B)
C)
D)
E)
Ans: E
Page 183
Chapter 17 Lipids and Their Functions in Biochemical Systems
48. What is another name for phosphatidylcholine?
A) phospholipid-D
D)
B) sphingosine
E)
C) cholinesterase
Ans: D
lecithin
chylomicron
49. Which lipid hormones allow tissues of the body to communicate with one another?
A) steroids B) lipoproteins C) enzymes D) arachidonates E) prostaglandins
Ans: A
50. Which steroid is responsible for both the successful initiation and completion of
pregnancy?
A) cholesterol
D) progesterone
B) sphingosine
E) cortisone
C) chylomicron
Ans: D
51. What is the general term for lipids synthesized from isoprene units?
A) cholesterol
D) terpenes
B) waxes
E) high density lipoproteins
C) chylomicrons
Ans: D
52. Which of the following substances do not occur in lipoproteins?
A) phospholipids B) cholesterol C) starch D) proteins E) triglycerides
Ans: C
53. High levels of one class of human plasma lipoprotein are thought to reduce the
incidence of atherosclerosis. Which class is this?
A) chylomicrons
B) VLDL
C) LDL
D) HDL
E) cholinesterases
Ans: D
Page 184
Chapter 17 Lipids and Their Functions in Biochemical Systems
54. Which of the following fatty acids would be classified as an omega-6 fatty acid?
A) I
B) II
C) III
D) I and III
E) II and III
Ans: D
55. Sphingomyelins are a type of sphingolipid, cell membrane lipids that contain
sphingosine, an 18-carbon amino alcohol, as the backbone of the structure. What type
of bond joins the fatty acid portion of the sphingomyelin molecule to the sphingosine
backbone?
A) C=C bond
B) amide bond
C) ionic bond
D) phosphodiester bond
E) hydrogen bond
Ans: B
56. Which of the following substances do not contribute to the structure of biological
membranes?
A) phospholipids
D) proteins
B) glycolipids
E) cellulose
C) cholesterol
Ans: E
Page 185
Chapter 17 Lipids and Their Functions in Biochemical Systems
57. Which steroid is used in the treatment of rheumatoid arthritis, asthma, and many skin
conditions?
A) testosterone B) cortisone C) digitoxin D) cholesterol E) stanozolol
Ans: B
58. How does the melting point of an unsaturated fatty acid compare to that of a saturated
fatty acid with an equal number of carbon atoms?
A) The melting point of the unsaturated fatty acid will be higher than that of the
saturated fatty acid.
B) The melting point of the unsaturated fatty acid will be lower than that of the saturated
fatty acid.
C) The melting point of the unsaturated fatty acid will be the same as that of the
saturated fatty acid.
D) It is impossible to predict without additional information.
E) Fatty acids do not have melting points because they are liquids at room temperature.
Ans: B
59. Which of the following is NOT a lipid?
A) fatty acids
B) glycerides
C) waxes
Ans: E
D)
E)
lipoproteins
All of the choices are correct.
60. Which statement concerning lipids is FALSE?
A) Lipids are used as an energy source.
B) Most of the energy stored in the body is in the form of lipids.
C) Glycogen is the lipid used for storing energy.
D) Lipids are stored in fat cells called adipocytes.
E) Lipids release more than twice the energy of carbohydrates when oxidized.
Ans: C
61. Which of the statements concerning the lipid bilayer of cell membranes is
INCORRECT?
A) The lipid bilayer consists of two identical layers of phospholipids.
B) The hydrophobic hydrocarbon tails are located in the interior of the bilayer.
C) The ionic head groups of lipids are exposed on the exterior surface of the bilayer.
D) The hydrocarbon tails provide a thin shell of nonpolar material that prevents
mixing of molecules on both sides of the bilayer.
E) Carbohydrate groups attached to the outer surface of the lipid bilayer participate
in receptor and recognition functions.
Ans: A
Page 186
Chapter 17 Lipids and Their Functions in Biochemical Systems
62. Which of the following best describes the composition of a saturated fatty acid?
A) contains cis- and trans- C=C bonds
B) contains only C−C bonds
C) contains at least one C−C bond
D) contains only C=C bonds
E) contains alternating C−C and C=C bonds
Ans: B
63. Which of the following leads to an increase in the melting point of a fatty acid?
A) increase in the length of the carbon chain
B) increase in the amount of unsaturation
C) decrease in the number of hydrogen atoms per carbon atom
D) All of the choices are correct.
E) None of the choices are correct.
Ans: A
64. What is the IUPAC name of the carboxylic acid formed by the hydrogenation of oleic
acid (cis-9-octadecenoic acid)?
A) trans-9-octadecenoic acid
D) 9-octadecenoic acid
B) octadecanoic acid
E) octadecanol
C) octadecenoic acid
Ans: B
65. Which of the following is the reverse of an esterification reaction?
A) reduction of an ester
D) hydrolysis of an ester
B) oxidation of an ester
E) hydrogenation of an ester
C) neutralization of an ester
Ans: D
66. Which type of lipid always contains the carbon skeleton structure shown?
A) lipoproteins
Ans: E
B) glycerides
C) phospholipids
D) sphingolipids
E) steroids
67. A correlation appears to exist between large quantities of saturated fats in the diet and
several forms of cancer.
Ans: True
68. All lipid molecules have a polar “head” and a nonpolar “tail.”
Ans: False
Page 187
Chapter 17 Lipids and Their Functions in Biochemical Systems
69. Unsaturated fatty acids contain only single bonds in their hydrocarbon chains.
Ans: False
70. One mole of oleic acid will react with two moles of hydrogen to form a mole of stearic
acid.
Ans: False
71. The two essential fatty acids are oleic and linoleic acid.
Ans: False
72. Prostaglandins produced in the kidneys cause renal blood vessels to dilate.
Ans: True
73. Phospholipids have a polar “head” and a nonpolar “tail.”
Ans: True
74. The most abundant lipids found in membranes are the phosphoglycerides.
Ans: True
75. The melting point of saturated fatty acids decreases with increasing number of carbons.
Ans: False
76. The product of the reaction of decanoic acid with n-propanol under acidic conditions is
isopropyl decanoate.
Ans: False
77. A strong correlation exists between heart disease and the concentration of cholesterol
found in blood plasma.
Ans: True
78. Bile salts are classified as steroids.
Ans: True
79. Fatty acids react with long chain alcohols to produce waxes.
Ans: True
80. Organisms which live at high temperatures tend to have higher proportions of
unsaturated fatty acids in their cell membranes.
Ans: False
81. The cell membrane controls the flow of metabolites into and out of a cell.
Ans: True
Page 188