Lipid Structure and Metabolism Flashcards
1
Q
Phospholipases are designated A, B, etc, based on
a. the different sites in the molecule where they cleave the
phospholipids.
b. whether they are phosphorylases or hydrolases.
c. whether they use NAD as a cofactor.
d. whether they use ATP as a cofactor.
A
a. the different sites in the molecule where they cleave the
phospholipids
2
Q
Phospholipases break down fats by
a. adding a phosphate group to them.
b. reducing the double bonds to single
bonds.
c. hydrolyzing them.
d. removing acetyl-CoA units.
e. none of these
A
c. hydrolyzing them.
3
Q
Which of the following is true concerning phospholipases?
a. Many snake venoms contain phospholipases
b. Phospholipase D is a component in some spider venoms
c. Phospholipases in snake venoms can lead to the lysing of blood
cells
d. All of these
A
d. All of these
4
Q
The bond linking a fatty acid to coenzyme A is
a. an ester.
b. a thioester.
c. an
anhydride.
d. an ether.
e. none of these
A
b. a thioester.
5
Q
Which of the following statements below about the activation of fatty acids is false?
a.Activation involves the formation of a high energy thioester bond.
b.Activation is accompanied by hydrolysis of ATP to ADP and Pi.
c.Activation includes the formation of an acyl-adenylate intermediate.
d.Activation includes hydrolysis of ATP to produce AMP and PPi, with the further
hydrolysis of PPi to drive the reaction to completion.
A
b.Activation is accompanied by hydrolysis of ATP to ADP and Pi.
6
Q
The carrier molecule which transports fatty acids through the inner mitochondrial membrane is
a. ATP.
b. Carnitine.
c. Coenzyme
A.
d. Lipoic Acid.
e. none of these
A
b. Carnitine.
7
Q
Which of the following reactions is catalyzed by carnitine acyltransferase?
a. carnitine + acyl-CoA–> CoASH + acylcarnitine
b. CoASH + acylcarnitine–> carnitine + acyl-CoA
c. both of these
d. none of these
A
c. both of these
8
Q
Which of the following is not true regarding catabolism of triacylglycerols?
a.Control of release of fatty acids from triacylglycerols in adipocytes involves cyclic
AMPasasecond messenger.
b.When cAMP is a second messenger in the catabolsim of triacylglycerols, it activates a
protein kinase
c.The protein kinase, once activated, cleaves fatty acids from the triacylglycerol
d.The phosphorylated form of triacylglycerol lipase is the active form
e.All of these are true
A
c.The protein kinase, once activated, cleaves fatty acids from the triacylglycero
9
Q
The use of cyclic AMP to mobilize fatty acids from adipose tissue is analogous to cyclic AMPs
role in mobilization of sugars from glycogen in the liver.
a. True
b. False
A
a. True
10
Q
Which of the following statements concerning β-oxidation of fatty acids is false?
a. Initiation occurs at the methyl end of the fatty acid.
b. β-oxidation is the primary route for degradation of fatty acids.
c. β-oxidation takes place in the mitochondrial matrix.
d. Two-carbon units are successively eliminated with each round.
A
a. Initiation occurs at the methyl end of the fatty acid.
11
Q
The metabolically activated form of a fatty acid is
a. an ester
b. a Schiff base
c. a phosphate ester
d. a thioester
e. none of these
A
d. a thioester
12
Q
Where in the cell does β-oxidation occur?
a. Cytoplasm.
b. Outer mitochondrial membrane.
c. Mitochondrial intermembrane
space.
d. Inner mitochondrial membrane.
e. Mitochondrial matrix.
A
e. Mitochondrial matrix.
13
Q
When an acyl group is being transferred from the cytosol to the mitochondria for oxidation,
the order of the enzymes it encounters is:
a. CPT-I: Carnitine Translocase: CPT-II
b. Carnitine Translocase: CPT-I: CPT-II
c. CPT-II: Carnitine Translocase: CPT-I
d. none of these
A
a. CPT-I: Carnitine Translocase: CPT-II
14
Q
Which of the following best describes carnitine?
a. It transports fatty acids across the inner mitochondrial membrane for breakdown.
b. It transports acetyl-CoA to the cytosol for fatty acid synthesis.
c. It’s a precursor of cholesterol.
d. It carries growing acyl chains during fatty acid synthesis.
e. none of these
A
a. It transports fatty acids across the inner mitochondrial membrane for breakdown.
15
Q
Carnitine acyltransferase is located in the mitochondrial
a. intermembrane
space.
b. outer membrane.
c. inner membrane.
d. matrix.
A
c. inner membrane
16
Q
(see picture)
16. The enzyme activity catalyzing the reaction shown is best termed a
a. reductase
b. hydratase
c. dehydratase
d. dehydrogenase
A
d. dehydrogenase
17
Q
(see picture)
17. Which group of small molecules best fit the boxes associated with the reaction shown?
a. I
b. II
c. III
d. IV
A
b. II
18
Q
he first three reactions of the β-oxidation cycle of fatty acids produce
a. two moles of NADH
b. two moles of FADH2
c. one mole each of NADH and FADH2
d. two moles of ATP
A
c. one mole each of NADH and FADH2
19
Q
Which of the following is not a product of the activation of fatty acids?
a. A thioester
b. ADP
c. Pyrophosphate
d. Phosphate
e. All of these are products of the activation of a fatty
acid.
A
b. ADP
20
Q
Fatty acid catabolism is called β-oxidation, since the second or β carbon from the carboxyl
group is the site of oxidation.
a. True
b. False
A
a. True
21
Q
Palmitic acid, with 16 carbons, requires 8 cycles of β-oxidation to produce 8 acetyl-CoA.
a. True
b. False
A
b. False
22
Q
How many cycles of β-oxidation are required to convert stearic acid (18 carbons) to 9
acetyl-CoAs?
a. 6
b. 8
c. 9
d. 18
e. none of
these
A
b. 8
23
Q
The reactions involved in β-oxidation of fatty acids include the following:
1. Cleavage of acetyl-CoA from the fatty acid
2. Hydration of a double bond.
3. Formation of a C−C double bond.
4. Oxidation of an alcohol.
The correct order of these reactions is:
A
3 →2→4→1
24
Q
Which of the following vitamins and cofactors is not used in β-oxidation?
a. Biotin
b. Niacin
c. Pantothenic acid
d. Riboflavin
e. All of these are important in the β-oxidation of fatty
acids.
A
a. Biotin
25
. How many NAD+are reduced in the degradation of palmitoyl-CoA to form eight molecules
of acetyl-CoA?
a. 1
b. 7
c. 8
d. 14
e. 16
b. 7
26
Which of the following is true about the oxidation steps in β-oxidation of fatty acids?
a. NAD+ is the cosubstrate when the oxidation creates a double bond
b. FAD is the cosubstrate when the oxidation produces a carbonyl group
c. FAD is the cosubstrate when the oxidation creates a double bond
d. either NAD+ or FAD can be used to create a double bond
e. none of these
c. FAD is the cosubstrate when the oxidation creates a double bond
27
The processing of one molecule of stearic acid (18 carbons) by β-oxidation
a. requires 8 cycles of β-oxidation and produces 9 molecules of acetyl-CoA.
b. requires 8 cycles of β-oxidation and produces 8 molecules of acetyl-CoA.
c. requires 9 cycles of β-oxidation and produces 8 molecules of acetyl-CoA.
d. requires 9 cycles of β-oxidation and produces 9 molecules of acetyl-CoA.
a. requires 8 cycles of β-oxidation and produces 9 molecules of acetyl-CoA.
28
How many ATPs can be netted from the complete oxidation of palmitate (C16) to CO2 & H2O?
a. ATPs ≤ 40
b. 40 < ATPs ≤ 80
c. 80 < ATPs ≤ 120
d. 1200 < ATPs
c. 80 < ATPs ≤ 120
29
Approximately how many ATP molecules are netted from the complete oxidation of stearic
acid (C−18)?
a. 2
b. 4
c. 32
d. 88
e. 120
e. 120
30
Lipids yield more ATP than sugars because
a. they have more carbon atoms than sugars.
b. their carbon atoms are more highly
reduced.
c. both of these
d. neither of these
c. both of these
31
Which of the following is not true?
a.One advantage of the β-oxidation of fats compared to oxidation of sugars is that fatty
acids produce more metabolic water.
b.The oxidation of fats produces more energy per carbon than the oxidation of
carbohydrates
c.Fat yields more energy than carbohydrates because it is more oxidized
d.For every cycle of oxidation of a fatty acid, one NADH and one FADH2 are produced
c.Fat yields more energy than carbohydrates because it is more oxidized
32
Which of the following is not an advantage of fatty acids as a form of energy storage?
a. Fatty acids contain more highly reduced carbons than carbohydrates.
b. Their hydrophobic nature allows close packing in adipose tissue.
c. Storage of fats in muscle tissue makes it readily available for use during activity.
d. Fats contain more energy per gram than sugars.
e. They do not require water for storage.
c. Storage of fats in muscle tissue makes it readily available for use during activity.
33
The oxidation of unsaturated fatty acids specifically requires
a. a cis-trans isomerase and a reductase.
b. a cis-trans isomerase and a dehydrogenase.
c. a dehydrogenase and a reductase.
d. a dehydrogenase and a hydrase.
e. none of these
a. a cis-trans isomerase and a reductase.
34
A key intermediate in the catabolism of fatty acids with uneven numbers of carbon atoms is
a. malonyl-CoA
b. propionyl-CoA
c. oxaloacetate
d. phosphoenolpyruvate
b. propionyl-CoA
35
The β-oxidation of fatty acids with an odd number of carbons requires additional enzymes to
allow all the products to enter the citric acid cycle .
a. True
b. False
a. True
36
When is propionyl-CoA carboxylase required for the complete oxidation of a fatty acid?
a. When it has an even number of carbons.
b. When it has an odd number of carbons.
c. When it is a monounsaturated fatty
acid.
d. When it is a polyunsaturated fatty acid.
e. Never
b. When it has an odd number of carbons.
37
The conversion of methylmalonyl-CoA to succinyl-CoA involves which of these cofactors?
a. thiamine
pyrophosphate
b. Vitamin B12
c. NAD
d. biotin
b. Vitamin B12
38
The oxidation of an unsaturated fatty acid leads to the production of fewer ATPs than a
saturated fatty acid with the same number of carbons because ____
a.the oxidation of the fatty acid stops when it reaches the double bond
b.unsaturated fatty acids cannot be metabolized
c.the double bond results in the bypassing of the first oxidation step of the pathway,
thereby eliminating one FADH product
d.none of these
c.the double bond results in the bypassing of the first oxidation step of the pathway,
thereby eliminating one FADH product
39
The cis double bonds of naturally-occurring fatty acids react well with the hydratase enzyme.
a. True
b. False
b. False
40
The β-oxidation of unsaturated fatty acids requires additional enzymes to isomerize the
double bonds.
a. True
b. False
a. True
41
The unsaturated fatty acids that are intermediates in the β-oxidation cycle have what
orientation around the double bond?
a. the cis orientation
b. the trans orientation
c. can have either orientation
d. the orientation is not
known
b. the trans orientation
42
Isomerization of the double bonds of polyunsaturated fatty acids involves both cis-trans
isomerization and changing the position of the double bonds.
a. True
b. False
a. True
43
The yield of ATP from oxidation of an unsaturated fatty acid has what relationship to the yield
from the oxidation of a saturated fatty acid with the same number of carbon atoms?
a. less
b. greater
c. the same
d. not possible to determine from the information in this
chapter
a. less
44
A key intermediate in the formation of "ketone bodies" is
a. succinyl-CoA
b. methyl malonyl-CoA
c. propionyl-CoA
d. acetoacetyl-CoA
d. acetoacetyl-CoA
45
"Ketone bodies" are formed when
a. oxaloacetate is converted to acetoacetyl-CoA.
b. there is a deficiency of acetyl-CoA.
c. there is not enough oxaloacetate to react with available acetyl-CoA.
d. an organism consumes excessive amounts of carbohydrate compared to its lipid
intake.
e. none of these
c. there is not enough oxaloacetate to react with available acetyl-CoA.
46
What effect do high concentrations of ketone bodies have on blood pH?
a. They tend to lower blood pH.
b. They tend to increase blood pH.
c. They have no effect on blood
pH.
a. They tend to lower blood pH.
47
Which of the following is not true regarding ketone bodies?
a.Ketone bodies form during the catabolism of fats.
b.Ketone bodies are an effective means for weight loss, since the body will excrete them
in the urine.
c.The first enzyme used in the production of ketone bodies is thiolase
d.Ketone bodies are always an alternative fuel in all tissues
d.Ketone bodies are always an alternative fuel in all tissues
48
Which are the three most common ketone bodies?
a. Acetone, formaldehyde, acetoacetate.
b. Acetone, butyric acid and oxaloacetate.
c. Acetone, β-hydroxybutyrate and acetoacetate.
d. Acetone, β-hydroxybutyrate and oxaloacetate.
c. Acetone, β-hydroxybutyrate and acetoacetate.
49
Acetyl-CoA carboxylase uses which of these cofactors?
a. thiamine
pyrophosphate
b. Vitamin B12
c. NAD
d. biotin
d. biotin
50
Where in the cell does fatty acid synthesis occur?
a. Cytoplasm.
b. Outer mitochondrial membrane.
c. Mitochondrial intermembrane
space.
d. Inner mitochondrial membrane.
e. Mitochondrial matrix.
a. Cytoplasm.
51
Of the processes listed below, which is not an important source of acetyl-CoA?
a. pentose phosphate
pathway
b. amino acid degradation
c. glycolysis
d. fatty acid oxidation
a. pentose phosphate
pathway
52
How is acetyl-CoA transported from the mitochondria to the cytosol for fatty acid synthesis?
a.directly as acetyl-CoA
b.through a temporary linkage to carnitine
c.as citric acid
d.There is no reason to transport acetyl-CoA from the mitochondria to the cytosol, since
it is produced primarily in the cytosol.
c.as citric acid
53
Reduction reactions during fatty acid synthesis utilize
a. FADH2.
b. NADH.
c. NADPH.
d. FADH2 and NADH.
c. NADPH.
54
If the bicarbonate used in malonyl-CoA synthesis were labeled with 14C in the biosynthesis of
palmitate, where would the label be found in the reaction products?
a. CO2
b. C−16 of palmitate
c. C−1 of palmitate
d. evenly distributed in
palmitate
a. CO2
55
The addition of two-carbon units to a growing fatty acid chain is directly driven by
a. reduction of NADP+
b. oxidation of NADPH
c. decarboxylation of
malonyl-CoA
d. hydrolysis of ATP
c. decarboxylation of
malonyl-CoA
56
Which of the following statements concerning the anabolism and catabolism of fatty acids is
true?
a.Biotin is required for oxidation of fatty acids but not for anabolism.
b.NADPH is required for anabolism of fatty acids and not for catabolism.
c.Anabolism occurs in the intermembrane space of mitochondria while catabolism takes
place in the mitochondrial matrix.
d.Acetyl-CoA is not required for anabolism.
b.NADPH is required for anabolism of fatty acids and not for catabolism.
57
The primary function of biotin in metabolism is:
a. to allow for the addition of CO2 to other molecules.
b. to inhibit acetyl-CoA carboxylase
c. to inhibit carnitine palmitoyltransferase
d. all of these
e. none of these
a. to allow for the addition of CO2 to other molecules.
58
Since acetyl-CoA carboxylase is key to the synthesis of fatty acids, inhibitors of this enzyme
may be useful for weight loss or treatment of obesity.
a. True
b. False
a. True
59
Synthesis of fatty acids involves simple reversal of the β-oxidation cycle.
a. True
b. False
b. False
60
Fatty acid synthase binds growing fatty acids
a. by an ester linkage to a side chain of serine.
b. by a thioester linkage to a side chain of cysteines.
c. as a Schiff base to a side chain of lysine.
d. by a thioester linkage to a phosphopantetheine linked to a serine.
d. by a thioester linkage to a phosphopantetheine linked to a serine.
61
(see picture)
61. Which group of small molecules best fit the boxes associated with the reaction shown?
a. I
b. II
c. III
d. IV
c. III
62
(see picture)
62. The enzyme activity catalyzing the reaction shown is best termed a
a. reductase
b. ketothiolase
c. transferase
d. dehydratase
a. reductase
63
(see picture)
63. The enzyme activity catalyzing the reaction shown is best termed a
a. reductase
b. ketothiolase
c. transferase
d. dehydratase
d. dehydratase
64
The acyl carrier used in fatty acid synthesis is similar to coenzyme A.
a. True
b. False
a. True
65
During fatty acid synthesis, the growing fatty acid is always bound to a protein.
a. True
b. False
a. True
66
Which of the following mechanisms explains why fatty acid synthesis and breakdown do not
compete with each other in the body?
a. Synthesis and breakdown take place in two separate compartments of the
cell.
b. One process uses NADH/NAD+ and the other uses NADPH/NADP+.
c. They are not attached to the same carrier molecule in the two processes.
d. All of these mechanisms are in operation.
e. None of these
d. All of these mechanisms are in operation.
67
How many NADPHare oxidized in the synthesis of palmitoyl-CoA from eight molecules of
acetyl-CoA?
a. 1
b. 7
c. 8
d. 14
e. 16
d. 14
68
Compared to β-oxidation, fatty acid synthesis requires this extra vitamin or cofactor.
a. Biotin
b. Riboflavin
c. Niacin
d. Pantothenic acid
e. All of these are used in both pathways.
a. Biotin
69
Which of the following reactants is involved in both fatty acids synthesis and breakdown?
a. CO2.
b. Malonyl-CoA
c. NADPH.
d. Pantothenic acid.
e. All of these reactants are involved in both fatty acid synthesis and breakdown.
d. Pantothenic acid.
70
ACP used in fatty acid synthesis is an abbreviation for:
a. Acetyl-CoA phosphate.
b. Adenosine
cyclo-phosphate.
c. Acyl Carnitine Protein
d. Acyl Carrier Protein.
e. None of these is correct.
d. Acyl Carrier Protein.
71
Which of the following enzyme types is involved in both fatty acid synthesis and breakdown?
a. Carboxylase.
b. Transferase.
c. Synthase.
d. Both carboxylase and synthase.
e. All three of these enzymes are used in fatty acid
synthesis.
b. Transferase
72
Biosynthesis of compound lipids typically takes place
a. in the mitochondrial matrix
b. in the cytosol
c. on the endoplasmic reticulum
d. in the Golgi apparatus
e. none of these
c. on the endoplasmic reticulum
73
Which of the following is true about the FTO gene and obesity?
a.People with the FTO gene will be obese
b.Scientists know exactly how the FTO gene leads to obesity
c.Individuals with a specific variant of the FTO gene are a little over 1.5 times as likely
to be obese
d.All of these are true
c.Individuals with a specific variant of the FTO gene are a little over 1.5 times as likely
to be obese
74
Scientists think ACC2 may be a target to fight obesity because
a. Inhibiting ACC2 leads to lowered levels of malonyl-CoA
b. mice lacking ACC2 are leaner than wild-type mice
c. reducing malonyl-CoA relieves the inhibition of CPT-I
d. all of these
d. all of these
75
Other than their use in nucleic acid synthesis, which energy source is used uniquely for the
synthesis of lipids?
a. ATP
b. CTP
c. GTP
d. UTP
e. None of these is unique to fatty acid
synthesis.
b. CTP
76
The first committed precursor in the pathway for the synthesis of cholesterol is:
a. Isoprene
b. Lanosterol
c. Mevalonic acid
d. Squalene
e. None of these is correct.
c. Mevalonic acid
77
The ultimate precursor of all the carbon atoms in steroids is
a. acetyl-CoA (acetyl group)
b. oxaloacetate
c. succinyl-CoA (succinyl
group)
d. α-ketoglutarate
a. acetyl-CoA (acetyl group)
78
Isoprenoid derivatives play what role in steroid biosynthesis?
a. inhibit a key step
b. are key intermediates
c. compete with steroid biosynthesis for a limited
precursor
d. its role is unknown
b. are key intermediates
79
The cyclization reaction that produces lanosterol in the course of steroid biosynthesis is
remarkable because
a. it involves large molecules
b. it involves methyl groups
c. of the extreme conditions under which it takes
place
d. it is a concerted reaction
d. it is a concerted reaction
80
The committed step in cholesterol biosynthesis is catalyzed by
a. HMG-CoA synthase
b. HMG-CoA reductase
c. mevalonate kinase
d. squalene
monooxygenase
b. HMG-CoA reductase
81
Cholesterol is a precursor of all of the following except
a. cortisone
b. testosterone
c. progesterone
d. lanosterol
d. lanosterol
82
Drugs are available to lower cholesterol which actually inhibit its synthesis in the body.
a. True
b. False
a. True
83
Lipoproteins are incorporated into the cell by a process called pinocytosis.
a. True
b. False
b. False
84
Cholesterol can be made in the body; however, some must still be eaten in the diet, since we
cannot make enough to meet the demand.
a. True
b. False
b. False
85
The first true steroid synthesized in the steroid pathway is the following:
a. Cholesterol.
b. Squalene
c. Lanosterol
d. Progesterone
e. Mevalonic acid
c. Lanosterol
86
Which of the following is not a function of cholesterol in the human body?
a. Precursor of steroid hormones.
b. Energy storage compound.
c. Precursor of bile salts.
d. Component of cell membranes.
e. All of these are important function of cholesterol in humans.
b. Energy storage compound.
87
Which of the following is not associated with coronary heart disease?
a. high relative levels of HDLs
b. high levels of LDLs
c. absence or dysfunction of LDL receptors
d. serum cholesterol levels of 300 mg/dl or higher
a. high relative levels of HDLs
88
When the blood contains a high concentration of LDLs, the cells respond by making fewer
receptors to react with the LDL.
a. True
b. False
a. True
89
The human lipoproteins with the lowest density are
a. Chylomicrons
b. HDL.
c. IDL.
d. LDL.
e. VLDL.
a. Chylomicrons
90
The components of lipoproteins such as LDL and HDL which makes them water soluble are
a. proteins.
b. phospholipids.
c. unesterified cholesterol.
d. proteins and
phospholipids.
e. All of these
d. proteins and
phospholipids.
91
Which of the following are involved in the development of atherosclerosis?
a. Excess LDL
b. Inflammation
c. Adhesion
molecules
d. Monocytes
e. none of these
f. all of these
f. all of these
92
Obesity can lead to which of the following?
a. diabetes
b. heart attack
c. stroke
d. some forms of
cancer
e. all of these
e. all of these
93
Which of the following is true about neuropeptide Y?
a. it leads to increased appetite
b. it is a melanocortin
c. it leads to suppressed appetite
d. It is a steroid hormone
e. none of these
a. it leads to increased appetite
94
Which of the following is NOT a short term regulator of appetite?
a. ghrelin
b. Cholecystokinin
c. leptin
d. all of these are short term regulators
c. leptin
95
Leptin is
a. a peptide hormone
b. an appetite supressant
c. a hormone that stimulates fat breakdown
d. all of these
d. all of these
96
_____ hydrolyzes phospholipids at the surface of micelles.
a. PhospholipaseA1
b. Phospholipase D
c. Phospholipase A2
d. Phospholipase B
c. Phospholipase A2
97
Which of the following enzymes is involved in the esterification of a fatty acid for its
activation?
a. Acyl-CoA synthetase
b. Pyruvate
dehydrogenase
c. Aldolase
d. Phosphofructokinase
a. Acyl-CoA synthetase
98
_____ is a condition in which arteries are blocked to a greater or lesser extent by the
deposition of cholesterol plaques.
a. Angioedema
b. Atherosclerosis
c. Anterolisthesis
d. Alkaptonuria
b. Atherosclerosis
99
What characteristic is most used to define lipids?
A. ionic charge
B. melting point
C. solubility
D. ability to bind metal ions
C. solubility
100
Which of the following lipid molecules possess a different fundamental structural make-up from the others?
A. Fatty acids
B. Cholesterol
C. Triglycerides
D. Sphingolipids
E. Glycolipids
B. Cholesterol
101
What does amphipathic mean?
A. having both positive and negative charges
B. having both acid and base properties
C. having both hydrophilic and hydrophobic regions
D. having two stereoisomers
C. having both hydrophilic and hydrophobic regions
102
Which of the following statements is true?
A. All triacylglycerols and all phosphoacylglycerols have the same
fatty acids in them.
B. All triacylglycerols have the same fatty acids, but the fatty acids
in phosphoacylglycerols vary.
C. The fatty acids in triacylglycerols vary, but all phosphoacylglyc
erols have the same fatty acids in them.
D. The fatty acids in both triacylglycerols and in phosphoacylglycerols vary.
D. The fatty acids in both triacylglycerols and in phosphoacylglycerols vary.
103
How many hydroxyl groups does a molecule of glycerol have?
A. none
B. 1
C. 2
D. 3
E. 4
D. 3
104
Which of the following is true?
A. All fatty acids have an even number of carbons
B. Most fatty acids have an odd number of carbons
C. Fatty acids are equally likely to have an even number of carbons
as they are an odd number
D. Fatty acids with an odd number of carbons are more rare than those with an even number
D. Fatty acids with an odd number of carbons are more rare than those with an even number of carbons
105
Which of the following is not a characteristic of most fatty acids?
A. Presence of trans double bonds.
B. Even number of carbon atoms.
C. Only one carboxyl (-COOH) group.
D. Absence of conjugated double bonds.
E. All of these characterize lipids.
A. Presence of trans double bonds.
106
Unsaturated fatty acids usually have ____ double bonds.
A. cis
B. trans
A. cis
107
Which of the following compounds yields the most energy per
gram?
A. triacylglycerols
B. carbohydrates
C. proteins
D. They all yield about the same amount of energy per gram.
A. triacylglycerols
108
What kinds of bonds do lipase break in order to release fatty acids
from triacylglycerols?
A. esters
B. carbon-carbon single bonds
C. carbon-carbon double bonds
D. There are no fatty acids in triacylglycerols to release.
A. esters
109
Which of the following groups is not present in a phosphatidic acid?
A. Choline
B. Fatty acids
C. Glycerol
D. Phosphate
E. All of these are components of phosphatidic acid.
A. Choline
110
Which of the following groups is not present in a cerebroside?
A. Sphingosine
B. Fatty acid
C. Phosphate
D. Sugar
E. All of these can be components of cerebrosides.
C. Phosphate
111
Which of the following is not a product of saponification of a triglyceride?
A. Long chain fatty alcohols.
B. The salt of the fatty acids.
C. Soaps.
D. Glycerol.
E. All of these are products of saponification.
A. Long chain fatty alcohols.
112
Saponification is the hydrolysis of a(n)
A. peptide bond
B. ester bond
C. anhydride bond
D. glycosidic bond
B. ester bond
113
Which of the following groups is not present in lecithin?
A. Choline
B. Fatty acids
C. Glycerol
D. Phosphate
E. All of these are components of lecithin.
E. All of these are components of lecithin.
114
Which of the following alcohols is never found in phosphatides?
A. Ethanolamine
B. Serine
C. Inositol
D. Sugars
E. All of these can be components of phosphatides.
E. All of these can be components of phosphatides.
115
Which of the following lipids is not found in biological membranes?
A. triacylglycerols
B. phosphoacylglycerols
C. glycolipids
D. cholesterol
A. triacylglycerols
116
Glycolipids are characterized by containing the following non-lipid component:
A. Sugars
B. Glycerol
C. Phosphate
D. Sphingosine
E. More than one of these characterize glycolipids.
A. Sugars
117
Phospholipids are particularly important in these structures:
A. Membranes.
B. Lipoproteins.
C. The brain and nervous system.
D. Membranes, the brain and the nervous system.
E. All of these are correct
E. All of these are correct
118
Which of the following molecules is not amphipathic?
A. cholesterol
B. glucose
C. oleic acid
D. phosphatidylcholine
B. glucose
119
Which of the following is true?
A. Fatty acids with trans double bonds may be particularly unhealthy because they increase the ratio of LDLs to HDLs.
B. A fatty acid with 14 carbons and one trans double bond will behave more like a saturated fatty acid with 14 carbons than will
an unsaturated fatty acid with a cis double bond.
C. Fatty acids with trans double bonds can be formed by hydrogenation reaction of polyunssaturated fatty acids
D. fatty acids with trans double bonds tend to have higher melting points than those with cis double bonds all else being equal
E. All of these are correct
E. All of these are correct
120
Glycolipids are particularly important in these structures:
A. Membranes.
B. Lipoproteins.
C. The brain and nervous system.
D. Membranes, the brain and the nervous system.
E. All of these are correct.
D. Membranes, the brain and the nervous system.
121
Sphingolipids are particularly important in these structures:
A. Membranes
B. Lipoproteins
C. The brain and nervous system.
D. Membranes, the brain and the nervous system.
E. All of these are correct.
D. Membranes, the brain and the nervous system.
122
Which of the following groups is not present in sphingomyelin?
A. Sphingosine
B. Fatty acid
C. Phosphate
D. Sugar
D. Sugar
123
The HDL class of lipoprotein is generally believed to be preventative of heart disease.
A. True
B. False
A. True
124
Fatty acids with multiple double bonds are usually conjugated.
A. True
B. False
B. False
125
With what compound are fatty acids reacted to make a fat or oil?
A. cholesterol
B. glycerol
C. sphinganine
D. ceramide
B. glycerol
126
The myelin sheaths of neurons typically contain large amounts of
A. waxes
B. triacylglycerols
C. cholesterol
D. sphingolipids
D. sphingolipids
127
Lipids differ from most other biomolecules because they are defined on the basis of solubility, rather than on their chemical
structure.
A. True
B. False
A. True
128
Which of the following best describes lipids' insolubility in water?
A. They are typically very soluble.
B. They are typically insoluble.
C. There is no general trend as to lipids' solubility in water.
B. They are typically insoluble.
129
Glycolipids on the surface of cells are especially important as cell
markers.
A. True
B. False
A. True
130
Biological waxes are composed of
A. glycerol and only one fatty acid.
B. glycerol and two fatty acids
C. a fatty acid and a long-chain alcohol.
D. cholesterol and a fatty acid.
C. a fatty acid and a long-chain alcohol.
131
Multiple sclerosis is characterized by destruction of the myelin
sheath.
A. True
B. False
A. True
132
Which of the following cell types contains cholesterol?
A. bacteria
B. animal
C. plant
D. They all contain cholesterol.
B. animal
133
Cholesterol is particularly important as a component of animal
membranes.
A. True
B. False
A. True
134
Membrane lipids in a lipid bilayer are held together by
A. hydrophobic interactions
B. hydrogen bonds
C. electrostatic forces
D. covalent bonds
A. hydrophobic interactions
135
Cell membranes typically display asymmetry. What does this
mean?
A. The two leaves of a bilayer contain different collections of lipids
and proteins.
B. The fatty acyl chain on C-1 of a membrane lipid is usually
different from that on C-3.
C. Only one stereoisomer is ever seen at the chiral C-2 of the
glycerol residue in a membrane lipid.
D. Membrane lipids only have cis double bonds, never trans.
A. The two leaves of a bilayer contain different collections of lipids
and proteins
136
How does the presence of cis double bonds in fatty acids affect
membrane fluidity?
A. They tend to increase the fluidity.
B. They tend to decrease the fluidity.
C. They don't have any specific effect on fluidity.
A. They tend to increase the fluidity.
137
How does cholesterol affect membrane fluidity?
A. It tends to increase the fluidity.
B. It tends to decrease the fluidity.
C. It doesn't have any specific effect on fluidity.
B. It tends to decrease the fluidity.
138
Plants need cholesterol in their membranes to counteract the
rigidity of the cell wall.
A. True
B. False
B. False
139
Membranes are generally symmetrical, i.e., the outer face is composed of the same number and types of phospholipids as the inner face.
A. True
B. False
B. False
140
Which of the following would not be enriched on the outer side of the lipid bilayer compared to the inner side?
A. Phosphoacylglyerol
B. Ganglioside
C. Cerebroside
D. Sphingomyelin
A. Phosphoacylglyerol
141
The association of membrane proteins with lipids in the membrane
bilayer always involves
A. electrostatic interactions
B. hydrophobic interactions
C. covalent linkages
D. all of the above
B. hydrophobic interactions
142
The order-disorder transition (melting) in membranes
A. is cooperative
B. can be monitored by fluorescence techniques
C. can be monitored by spin labeling
D. all of these
D. all of these
143
How do the membranes of plant and animal cells compare?
A. Animal cell membranes tend to be more rigid than those of
plant cells.
B. Animal cell membranes tend to be more fluid than those of plant
cells.
C. Animal cell membranes tend to be more asymmetric than those
of plant cells.
D. Animal cell membranes tend to be more symmetric than those
of plant cells.
A. Animal cell membranes tend to be more rigid than those of
plant cells.
144
Which of the following is not true?
A. Plant oils are favored in the diet because they generally contain
more unsaturated fats than found in animal fats.
B. Unsaturated fatty acids are healthier for humans than saturated
ones
C. Heart disease can be correlated with diets high in saturated
fatty acids
D. Unsaturated fatty acids lead to higher levels of LDL than saturated fatty acids do
D. Unsaturated fatty acids lead to higher levels of LDL than saturated fatty acids do
145
The distribution of lipids in membranes is
A. uneven, with bulkier molecules on the exterior
B. characterized by even distribution of molecules
C. distinguished by the absence of cholesterol
D. not well understood
A. uneven, with bulkier molecules on the exterior
146
The degree of membrane fluidity depends on
A. the percentage of lipids that contain choline
B. the percentage of glycolipids
C. the percentage of fatty acids
D. the percentage of unsaturated fatty acids
D. the percentage of unsaturated fatty acids
147
I find that briefly washing cells in a buffered solution at pH 11 is effective for isolating a cell membrane-associated hormone receptor. (A standard growth solution for the cells is pH 7.) Which of following best fits this description?
A. This is an integral membrane protein that completely traverses
the cell membrane.
B. This is an integral membrane protein that only penetrates one
leaf of the cell membrane.
C. This is a peripheral membrane protein that probably inter
acts with membrane phospholipids using aspartate-mediated salt
bridges.
D. This is a peripheral membrane protein that probably interacts
with membrane phospholipids using lysine-mediated salt bridges.
D. This is a peripheral membrane protein that probably interacts
with membrane phospholipids using lysine-mediated salt bridges.
148
Which of the following is not a function or characteristic of membrane proteins?
A. Transport
B. Catalytic activity
C. Blood clotting
D. Receptor sites
C. Blood clotting
149
Where can membrane proteins be located?
A. entirely within the membrane
B. on the surface of the membrane
C. in either position
D. The position of membrane proteins has never been determined
C. in either position
150
When a membrane reaches its transition temperature, integral
membrane proteins dissociate from the bilayer.
A. True
B. False
B. False
151
Which property has not been observed for membrane proteins?
A. energy storage
B. transport of substances into and out of the cell
C. catalysis (enzymatic activity)
D. acting as a receptor
A. energy storage
152
The freeze-fracture technique of electron microscopy is useful in
studying membrane structure because
A. integral membrane proteins can be seen in association with one leaflet of the lipid bilayer
B. all the proteins can be removed from the membrane
C. the degree of order of the lipid bilayer can be determined
D. the presence of bound carbohydrates can be detected
A. integral membrane proteins can be seen in association with one leaflet of the lipid bilayer
153
Which of the following treatments would be most useful in separating an integral membrane protein from the lipid component of a cell membrane?
A. Change the pH.
B. Add a salt.
C. Add a detergent.
D. Add a mixture of proteases.
E. None of these. You can't separate an integral membrane protein
from the lipid.
C. Add a detergent.
154
Which of the following is the best phrase to describe the modern view of membrane structure?
A. Membranes are lipid-lipid bilayers.
B. Membranes are lipid-lipid bilayers with associated proteins.
C. Membranes are composed solely of lipids and proteins.
D. Membranes are a fluid mosaic of lipids and proteins.
E. Membranes are found only in eukaryotic cells.
D. Membranes are a fluid mosaic of lipids and proteins.
155
Liposomes are
A. artificial membrane-bounded structures used to deliver medications.
B. single-layered membranes.
C. mixed micelles involved in cholesterol transport among cells.
D. bilayers with the hydrophobic regions on the outside.
A. artificial membrane-bounded structures used to deliver medications.
156
In the fluid mosaic model of membrane structure
A. the proteins are specifically bonded to the lipids
B. the proteins "float" in the lipid bilayer
C. the proteins are sandwiched between the lipid molecules
D. the lipids are sandwiched between the protein molecules
B. the proteins "float" in the lipid bilayer
157
Passive transport is the same as:
A. simple diffusion
B. facilitated diffusion
C. active transport
D. primary active transport
A. simple diffusion
158
The mechanism of membrane transport may involve the following:
A. ATP hydrolysis.
B. Conformation change of membrane proteins.
C. Phosphorylation or dephosphorylation of membrane proteins.
D. ATP hydrolysis and conformation change of membrane proteins.
E. All of these are correct.
E. All of these are correct.
159
The difference between active transport and passive transport is that
A. concentration gradients are involved in one and not in the other.
B. glycolipids play a role in one and not in the other.
C. one requires expenditure of energy by the cell and the other does not.
D. ions are transported into and out of the cell by one process and
not by the other.
C. one requires expenditure of energy by the cell and the other does not.
160
Facilitated diffusion requires
A. a channel protein through which the transported substance
passes without binding
B. a carrier protein to which the transported substance binds
C. a receptor protein
D. expenditure of energy by the cell
B. a carrier protein to which the transported substance binds
161
Which of the following is not true?
A. Receptors are often invaginated into the cell after binding to
their specific molecule.
B. A given receptor type is present at a constant level on the
outside of a cell
C. In certain disease states, the level of a given receptor is in
creased or decreased
D. Binding of receptors to ligands sometimes shows hyperbolic
binding curves
B. A given receptor type is present at a constant level on the
outside of a cell
162
In the operation of the sodium-potassium pump
A. conformational changes in membrane proteins are inhibited
B. the ions involved bind to the lipid portion of the membrane
C. a membrane protein is phosphorylated with ATP as the source of the phosphate group
D. a membrane protein is phosphorylated with ADP as the source
of the phosphate group
C. a membrane protein is phosphorylated with ATP as the source of the phosphate group
163
What distinguishes primary from secondary active transport?
A. The requirement for protein.
B. The type of linkage to ATP hydrolysis
C. The number of kinds of molecules or ions transported
D. The relative direction of transport
B. The type of linkage to ATP hydrolysis
164
Which of the following methods of transport across a membrane does not require a protein?
A. Passive transport
B. Facilitated transport
C. Active Transport
D. Simple diffusion
D. Simple diffusion
165
Which of the following statements concerning active transport is true?
A. It takes place in the same direction as a concentration gradient.
B. It requires no expenditure of energy by the cell.
C. It can be compared to water running downhill.
D. A membrane-associate protein must be involved.
D. A membrane-associate protein must be involved.
166
A major difficulty in extracting receptor proteins from membranes
is that
A. it is difficult to remove the proteins from the membrane without
denaturation
B. there may be very few molecules of the protein in a cell
C. receptor proteins tend to have high molecular weights
D. all of these
D. all of these
167
In the sodium-potassium pump
A. sodium is transported out of the cell and potassium into the cell, both against concentration gradients
B. sodium is transported into the cell and potassium out of the cell,
both against concentration gradients
C. sodium is transported out of the cell and potassium into the cell,
both in the same direction as concentration gradients
D. sodium and potassium are both transported out of the cell
against concentration gradients
A. sodium is transported out of the cell and potassium into the cell, both against concentration gradients
168
A useful method for studying membrane proteins in place in the
membrane is
A. nuclear magnetic resonance
B. x-ray crystallography
C. treatment with mercaptoethanol
D. treatment with detergents
A. nuclear magnetic resonance
169
Glycoproteins on the cell surface are involved in this type of
function:
A. Cell identification
B. Receptor sites
C. Immune function
D. Cell identification and receptor sites
E. All of these are correct.
E. All of these are correct.
170
The key reaction of eyesight (in dim light) involving vitamin A is:
A. Reaction of the protein complex called Rhodopsin.
B. A cis-trans isomerization of a double bond.
C. Bleaching of a pigment in the retina.
D. Reaction of Rhodopsin and cis-trans isomerization of a double
bond.
E. All of these
E. All of these
171
These two lipid vitamins are often found in membranes:
A. A and D
B. A and E
C. D and E
D. E and K
E. None of these is the correct pair.
B. A and E
172
The following lipid vitamin is often used to preserve foods from
spoiling:
A. A
B. D
C. E
D. K
E. None of these preserves food.
C. E
173
Vitamin E has all of the following properties, except:
A. It is an antioxidant.
B. It can be made in the sunshine.
C. It is essential for at least some mammal's fertility.
D. It is often a component of membranes.
E. All of these describe vitamin E.
B. It can be made in the sunshine.
174
Rickets is caused by a deficiency in
A. vitamin A.
B. vitamin D.
C. vitamin E.
D. vitamin K.
B. vitamin D.
175
The vitamin needed for blood coagulation is
A. vitamin A
B. vitamin D
C. vitamin E
D. vitamin K
D. vitamin K
176
The vitamin classified as fat soluble rather than water soluble is
A. vitamin A
B. vitamin B1
C. vitamin B6
D. vitamin C
A. vitamin A
177
There are likely to be huge stores of lipid vitamins in healthy
animals.
A. True
B. False
A. True
178
Which of the following is not a lipid-soluble vitamin?
A. Ascorbic Acid
B. Cholicalciferol
C. Vitamin K
D. Retinol
E. Tocopherol
A. Ascorbic Acid
179
The following lipid vitamin has important involvement with calcium
ions:
A. A
B. D
C. E
D. K
E. More than one reacts with calcium ion.
E. More than one reacts with calcium ion.
180
Which of the following is a metabolic precursor of prostaglandins
& leukotrienes?
A. vitamin A.
B. arachidonic acid.
C. sphingomyelin.
D. cholesterol.
B. arachidonic acid.
181
Aspirin produces most of its analgesic effects by
A. binding to the plasma membrane of nerve cells
B. inhibiting the synthesis of vitamin A
C. inhibiting the synthesis of phospholipids
D. inhibiting the synthesis of prostaglandins
D. inhibiting the synthesis of prostaglandins
182
Which of the following does not belong in the list?
A. Retinol
B. Vitamin A
C. beta-carotene
D. Cholesterol
D. Cholesterol
