Download Examination #2 1) Which of the following is not one of the four major

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts

Biochemistry wikipedia, lookup

Nucleic acid analogue wikipedia, lookup

Proteolysis wikipedia, lookup

Deoxyribozyme wikipedia, lookup

Fatty acid metabolism wikipedia, lookup

Point mutation wikipedia, lookup

Amino acid synthesis wikipedia, lookup

Metalloprotein wikipedia, lookup

Glycolysis wikipedia, lookup

Metabolism wikipedia, lookup

Biosynthesis wikipedia, lookup

Evolution of metal ions in biological systems wikipedia, lookup

Basal metabolic rate wikipedia, lookup

Citric acid cycle wikipedia, lookup

Multi-state modeling of biomolecules wikipedia, lookup

Enzyme wikipedia, lookup

Oxidative phosphorylation wikipedia, lookup

Enzyme inhibitor wikipedia, lookup

Two-hybrid screening wikipedia, lookup

Photosynthetic reaction centre wikipedia, lookup

Transcript
Examination #2
1) Which of the following is not one of the four
major groups of macromolecules found in living
organisms?
A) glucose
B) carbohydrates
C) lipids
D) proteins
E) nucleic acids
Topic: Overview
Skill: Knowledge
2) Polymers of polysaccharides, fats, and proteins
are all synthesized from monomers by which
process?
A) connecting monosaccharides together
(condensation reactions)
B) the addition of water to each monomer
(hydrolysis)
C) the removal of water (dehydration reactions)
D) ionic bonding of the monomers
E) the formation of disulfide bridges between
monomers
Topic: Concept 5.1
Skill: Comprehension
3) Which of the following best summarizes the
relationship between dehydration reactions and
hydrolysis?
A) Dehydration reactions assemble polymers, and
hydrolysis breaks down polymers.
B) Hydrolysis only occurs in the urinary system,
and dehydration reactions only occur in the
digestive tract.
C) Dehydration reactions can occur only after
hydrolysis.
D) Hydrolysis creates monomers, and dehydration
reactions break down polymers.
E) A and C are correct.
Topic: Concept 5.2
Skill: Comprehension
4) A molecule with the chemical formula
C16H32O16 is probably a
A) carbohydrate.
B) lipid.
C) protein.
D) nucleic acid.
E) hydrocarbon.
Topic: Concept 5.2
Skill: Comprehension
Figure 5.1
5) If 128 molecules of the general type shown in
Figure 5.1 were covalently joined together in
sequence, the single molecule that would result
would be a
A) polysaccharide.
B) polypeptide.
C) polyunsaturated lipid.
D) monosaccharide.
E) disaccharide.
Topic: Concept 5.2
Skill: Comprehension
6) Consider a polysaccharide consisting of 576
glucose molecules. The total hydrolysis of the
polysaccharide would result in the production of
A) 575 glucose molecules.
B) 575 water molecules.
C) 576 glucose molecules.
D) A and B only
E) B and C only
Topic: Concept 5.2
Skill: Comprehension
7) Lactose, a sugar in milk, is composed of one
glucose molecule joined by a glycosidic linkage to
one galactose molecule. How is lactose classified?
A) as a pentose
B) as a hexose
C) as a monosaccharide
D) as a disaccharide
E) as a polysaccharide
Topic: Concept 5.2
Skill: Comprehension
8) Which of the following are polysaccharides?
A) glycogen
B) starch
C) chitin
D) A and B only
E) A, B, and C
Topic: Concept 5.2
Skill: Knowledge
9) Which of the following is true of both starch
and cellulose?
A) They are both polymers of glucose.
B) They are geometric isomers of each other.
C) They can both be digested by humans.
D) They are both used for energy storage in
plants.
E) They are both structural components of the
plant cell wall.
Topic: Concept 5.2
Skill: Knowledge
10) Which of the following is true of cellulose?
A) It is a polymer composed of sucrose monomers.
B) It is a storage polysaccharide for energy in
plant cells.
C) It is a storage polysaccharide for energy in
animal cells.
D) It is a major structural component of plant cell
walls.
E) It is a major structural component of animal
cell plasma membranes.
Topic: Concept 5.2
Skill: Knowledge
11) Humans can digest starch but not cellulose
because
A) the monomer of starch is glucose, while the
monomer of cellulose is galactose.
B) humans have enzymes that can hydrolyze the
beta (β) glycosidic linkages of starch but not the
alpha (α) glycosidic linkages of cellulose.
C) humans have enzymes that can hydrolyze the
alpha (α) glycosidic linkages of starch but not the
beta (β) glycosidic linkages of cellulose.
D) humans harbor starch-digesting bacteria in the
digestive tract.
E) the monomer of starch is glucose, while the
monomer of cellulose is maltose.
Answer: C
Topic: Concept 5.2
Skill: Comprehension
12) A molecule with the formula C18H36O2 is
probably a
A) carbohydrate.
B) lipid.
C) protein.
D) nucleic acid.
E) hydrocarbon.
Topic: Concept 5.3
Skill: Comprehension
13) Which of the following is (are) true for the
class of large biological molecules known as
lipids?
A) They are insoluble in water.
B) They are an important constituent of cell
membranes.
C) They contain twice as much energy as an
equivalent weight of polysaccharide.
D) Only A and B are correct.
E) A, B, and C are correct.
Topic: Concept 5.3
Skill: Knowledge
14) Triacylglycerol is a
A) protein with tertiary structure.
B) lipid made with three fatty acids and glycerol.
C) lipid that makes up much of the plasma
membrane.
D) molecule formed from three alcohols by
dehydration reactions.
E) carbohydrate with three sugars joined together
by glycosidic linkages.
Topic: Concept 5.3
Skill: Knowledge
15) Saturated fatty acids
A) are the predominant fatty acid in corn oil.
B) have double bonds between carbon atoms of
the fatty acids.
C) have a higher ratio of hydrogen to carbon than
do unsaturated fatty acids.
D) are usually liquid at room temperature.
E) are usually produced by plants.
Answer: C
Topic: Concept 5.3
Skill: Knowledge
Figure 5.2
16) What is the molecule illustrated in Figure 5.2?
A) a saturated fatty acid
B) an unsaturated fatty acid
C) a polyunsaturated triacylglyceride
D) a trans polyunsaturated triacylglyceride
E) a steroid similar to cholesterol
Topic: Concept 5.3
Skill: Knowledge
E) polymer of amino acids.
Topic: Concept 5.4
Skill: Knowledge
Figure 5.3
17) The molecule shown in Figure 5.3 is a
A) polysaccharide.
B) polypeptide.
C) saturated fatty acid.
D) triacylglycerol.
E) unsaturated fatty acid.
Topic: Concept 5.3
Skill: Knowledge
18) The hydrogenation of vegetable oil would
result in which of the following?
A) a decrease in the number of carbon-carbon
double bonds in the oil (fat) molecules
B) an increase in the number of hydrogen atoms in
the oil (fat) molecule
C) the oil (fat) being a solid at room temperature
D) A and C only
E) A, B, and C
Topic: Concept 5.3
Skill: Comprehension
21) The 20 different amino acids found in
polypeptides exhibit different chemical and
physical properties because of different
A) carboxyl groups attached to an alpha (α)
carbon
B) amino groups attached to an alpha (α) carbon
C) side chains (R groups).
D) alpha (α) carbons.
E) asymmetric carbons.
Topic: Concept 5.4
Skill: Knowledge
Figure 5.5
22) The chemical reaction illustrated in Figure 5.5
results in the formation of a (an)
A) ionic bond.
B) peptide bond.
C) glycosidic linkage.
D) ester linkage.
E) phosphodiester linkage.
Topic: Concept 5.4
Skill: Comprehension
Figure 5.4
19) What is the structure shown in Figure 5.4?
A) starch molecule
B) protein molecule
C) steroid molecule
D) cellulose molecule
E) phospholipid molecule
Topic: Concept 5.3
Skill: Knowledge
20) A polypeptide can best be described as a
A) monomer of a protein polymer.
B) polymer containing 20 amino acid molecules.
C) polymer containing 19 peptide bonds.
D) polymer containing 20 peptide bonds.
23) The bonding of two amino acid molecules to
form a larger molecule requires which of the
following?
A) removal of a water molecule
B) addition of a water molecule
C) formation of an ionic bond
D) formation of a hydrogen bond
E) both A and C
Topic: Concept 5.4
Skill: Comprehension
24) Polysaccharides, lipids, and proteins are
similar in that they
A) are synthesized from monomers by the process
of hydrolysis.
B) are synthesized from monomers by
dehydration reactions.
C) are synthesized as a result of peptide bond
formation between monomers.
D) are decomposed into their subunits by
dehydration reactions.
E) all contain nitrogen in their monomer building
blocks.
Topic: Concepts 5.1-5.4
Skill: Knowledge
25) Dehydration reactions are used in forming
which of the following compounds?
A) triacylglycerides
B) polysaccharides
C) proteins
D) A and C only
E) A, B, and C
Topic: Concepts 5.1-5.4
Skill: Knowledge
26) Upon chemical analysis, a particular protein
was found to contain 556 amino acids. How many
peptide bonds are present in this protein?
A) 139
B) 554
C) 555
D) 556
E) 558
Topic: Concept 5.4
Skill: Comprehension
Refer to Figure 5.6 to answer the following
questions.
Figure 5.6
27) At which bond would water need to be added
to achieve hydrolysis of the peptide, back to its
component amino acid?
Topic: Concept 5.4
Skill: Comprehension
28) Which bond is closest to the N-terminus of
the molecule?
Topic: Concept 5.4
Skill: Comprehension
29) Which bond is closest to the C-terminus of the
molecule?
Topic: Concept 5.4
Skill: Comprehension
30) How many different kinds of polypeptides,
each composed of 12 amino acids, could be
synthesized using the 20 common amino acids?
A) 412
B) 1220
C) 125
D) 20
E) 2012
Topic: Concept 5.4
Skill: Application
31) Which bonds are created during the
formation of the primary structure of a protein?
A) peptide bonds
B) hydrogen bonds
C) disulfide bonds
D) phosphodiester bonds
E) A, B, and C
Topic: Concept 5.4
Skill: Knowledge
32) What maintains the secondary structure of a
protein?
A) peptide bonds
B) hydrogen bonds
C) disulfide bonds
D) ionic bonds
E) phosphodiester bonds
Topic: Concept 5.4
Skill: Knowledge
33) Which type of interaction stabilizes the alpha
(α) helix and the beta (β) pleated sheet structures
of proteins?
A) hydrophobic interactions
B) nonpolar covalent bonds
C) ionic bonds
D) hydrogen bonds
E) peptide bonds
Topic: Concept 5.4
Skill: Knowledge
34) The α helix and the β pleated sheet are both
common polypeptide forms found in which level
of protein structure?
A) primary
B) secondary
C) tertiary
D) quaternary
E) all of the above
Topic: Concept 5.4
Skill: Knowledge
folded polypeptide.
D) organization of a polypeptide chain into an α
helix or β pleated sheet.
E) overall protein structure resulting from the
aggregation of two or more polypeptide subunits.
Topic: Concept 5.4
Skill: Knowledge
38) A strong covalent bond between amino acids
that functions in maintaining a polypeptide's
specific three-dimensional shape is a (an)
A) ionic bond.
B) hydrophobic interaction.
C) van der Waals interaction.
D) disulfide bond.
E) hydrogen bond.
Topic: Concept 5.4
Skill: Knowledge
Figure 5.7
35) Figure 5.7 shows the
A) 1-4 linkage of the α glucose monomers of
starch.
B) 1-4 linkage of the β glucose monomers of
cellulose.
C) double helical structure of a DNA molecule.
D) α helix secondary structure of a polypeptide.
E) β pleated sheet secondary structure of a
polypeptide.
Topic: Concept 5.4
Skill: Comprehension
36) Figure 5.7 best illustrates the
A) secondary structure of a polypeptide.
B) tertiary structure of a polypeptide.
C) quaternary structure of a protein.
D) double helix structure of DNA.
E) primary structure of a polysaccharide.
Topic: Concept 5.4
Skill: Comprehension
37) The tertiary structure of a protein is the
A) bonding together of several polypeptide chains
by weak bonds.
B) order in which amino acids are joined in a
polypeptide chain.
C) unique three-dimensional shape of the fully
39) At which level of protein structure are
interactions between the side chains (R groups)
most important?
A) primary
B) secondary
C) tertiary
D) quaternary
E) all of the above
Topic: Concept 5.4
Skill: Knowledge
40) The R group or side chain of the amino acid
serine is –CH2-OH. The R group or side chain of the
amino acid alanine is –CH3. Where would you
expect to find these amino acids in a globular
protein in aqueous solution?
A) Serine would be in the interior, and alanine
would be on the exterior of the globular protein.
B) Alanine would be in the interior, and serine
would be on the exterior of the globular protein.
C) Both serine and alanine would be in the interior
of the globular protein.
D) Both serine and alanine would be on the
exterior of the globular protein.
E) Both serine and alanine would be in the interior
and on the exterior of the globular protein.
Topic: Concept 5.4
Skill: Application
41) The globular protein transthyretin results
from the aggregation of four polypeptide subunits.
Each of the subunits is a polypeptide chain with an
α helix region. Which structure(s) must the
transthyretin protein have?
A) primary structure
B) primary and secondary structure
C) primary, secondary, and tertiary structure
D) primary, secondary, tertiary, and quaternary
structure
E) primary, secondary, tertiary, quaternary, and
alpha structure
Topic: Concept 5.4
Skill: Comprehension
42) What would be an unexpected consequence
of changing one amino acid in a protein consisting
of 325 amino acids?
A) The primary structure of the protein would be
changed.
B) The tertiary structure of the protein might be
changed.
C) The biological activity or function of the protein
might be altered.
D) Only A and C are correct.
E) A, B, and C are correct.
Topic: Concept 5.4
Skill: Comprehension
43) Altering which of the following levels of
structural organization could change the function
of a protein?
A) primary
B) secondary
C) tertiary
D) quaternary
E) all of the above
Topic: Concept 5.4
Skill: Comprehension
44) All of the following molecules are proteins
except
A) hemoglobin.
B) transthyretin.
C) collagen.
D) lysozyme.
E) glycogen.
Topic: Concept 5.4
Skill: Knowledge
45) What is the term used for a change in a
protein's three-dimensional shape or
conformation due to disruption of hydrogen
bonds, disulfide bridges, or ionic bonds?
A) hydrolysis
B) stabilization
C) destabilization
D) renaturation
E) denaturation
Topic: Concept 5.4
Skill: Knowledge
46) What is the term used for a protein molecule
that assists in the proper folding of other
proteins?
A) tertiary protein
B) chaperonin
C) enzyme protein
D) renaturing protein
E) denaturing protein
Topic: Concept 5.4
Skill: Knowledge
47) Of the following functions, the major purpose
of RNA is to
A) transmit genetic information to offspring.
B) function in the synthesis of protein.
C) make a copy of itself, thus ensuring genetic
continuity.
D) act as a pattern or blueprint to form DNA.
E) form the genes of higher organisms.
Topic: Concept 5.5
Skill: Comprehension
48) Which of the following best describes the flow
of information in eukaryotic cells?
A) DNA → RNA → proteins
B) RNA → proteins → DNA
C) proteins → DNA → RNA
D) RNA → DNA → proteins
E) DNA → proteins → RNA
Topic: Concept 5.5
Skill: Comprehension
49) Which of the following descriptions best fits
the class of molecules known as nucleotides?
A) a nitrogenous base and a phosphate group
B) a nitrogenous base and a pentose sugar
C) a nitrogenous base, a phosphate group, and a
pentose sugar
D) a phosphate group and an adenine or uracil
E) a pentose sugar and a purine or pyrimidine
Topic: Concept 5.5
Skill: Knowledge
50) Which of the following are nitrogenous bases
of the pyrimidine type?
A) guanine and adenine
B) cytosine and uracil
C) thymine and guanine
D) ribose and deoxyribose
E) adenine and thymine
Answer: B
Topic: Concept 5.5
Skill: Knowledge
51) Which of the following are nitrogenous bases
of the purine type?
A) cytosine and guanine
B) guanine and adenine
C) adenine and thymine
D) thymine and uracil
E) uracil and cytosine
Topic: Concept 5.5
Skill: Knowledge
52) All of the following nitrogenous bases are
found in DNA except
A) thymine.
B) adenine.
C) uracil.
D) guanine.
E) cytosine.
Topic: Concept 5.5
Skill: Knowledge
53) A double-stranded DNA molecule contains a
total of 120 purines and 120 pyrimidines. This
DNA molecule could be comprised of
A) 120 adenine and 120 uracil molecules.
B) 120 thymine and 120 adenine molecules.
C) 120 cytosine and 120 thymine molecules.
D) 240 adenine and 240 cytosine molecules.
E) 240 guanine and 240 thymine molecules.
Topic: Concept 5.5
Skill: Application
54) The difference between the sugar in DNA and
the sugar in RNA is that the sugar in DNA
A) is a six-carbon sugar and the sugar in RNA is a
five-carbon sugar.
B) can form a double-stranded molecule.
C) has a six-membered ring of carbon and
nitrogen atoms.
D) can attach to a phosphate.
E) contains one less oxygen atom.
Topic: Concept 5.5
Skill: Knowledge
55) Which of the following statements best
summarizes the structural differences between
DNA and RNA?
A) RNA is a protein, whereas DNA is a nucleic acid.
B) DNA is a protein, whereas RNA is a nucleic acid.
C) DNA nucleotides contain a different sugar than
RNA nucleotides.
D) RNA is a double helix, but DNA is singlestranded.
E) A and D are correct.
Topic: Concept 5.5
Skill: Knowledge
56) In the double helix structure of nucleic acids,
cytosine hydrogen bonds to
A) deoxyribose.
B) ribose.
C) adenine.
D) thymine.
E) guanine.
Topic: Concept 5.5
Skill: Knowledge
57) The two strands making up the DNA double
helix molecule
A) cannot be separated.
B) contain ribose and deoxyribose in opposite
strands.
C) are held together by hydrogen bonds.
D) are attached through a phosphate to hold the
strands together.
E) contain uracil but not thymine.
Topic: Concept 5.5
Skill: Knowledge
58) If one strand of a DNA molecule has the
sequence of bases 5'ATTGCA3', the other
complementary strand would have the sequence
A) 5'TAACGT3'.
B) 3'TAACGT5'.
C) 5'UAACGU3'.
D) 3'UAACGU5'.
E) 5'UGCAAU3'.
Topic: Concept 5.5
Skill: Knowledge
59) The structural feature that allows DNA to
replicate is the
A) sugar-phosphate backbone.
B) complementary pairing of the nitrogenous
bases.
C) disulfide bonding (bridging) of the two helixes.
D) twisting of the molecule to form an α helix.
E) three-component structure of the nucleotides.
Topic: Concept 5.5
Skill: Knowledge
60) A new organism is discovered in the forests of
Costa Rica. Scientists there determine that the
polypeptide sequence of hemoglobin from the
new organism has 72 amino acid differences from
humans, 65 differences from a gibbon, 49
differences from a rat, and 5 differences from a
frog. These data suggest that the new organism
A) is more closely related to humans than to frogs.
B) is more closely related to frogs than to humans.
C) may have evolved from gibbons but not rats.
D) is more closely related to humans than to rats.
E) may have evolved from rats but not from
humans and gibbons.
Topic: Concept 5.5
Skill: Application
61) Which of the following is an example of
hydrolysis?
A) the reaction of two monosaccharides, forming a
disaccharide with the release of water
B) the synthesis of two amino acids, forming a
peptide with the release of water
C) the reaction of a fat, forming glycerol and fatty
acids with the release of water
D) the reaction of a fat, forming glycerol and fatty
acids with the utilization of water
E) the synthesis of a nucleotide from a phosphate,
a pentose sugar, and a nitrogenous base with the
production of a molecule of water
Topic: Concepts 5.1-5.4
Skill: Comprehension
62) Large organic molecules are usually
assembled by polymerization of a few kinds of
simple subunits. Which of the following is an
exception to this statement?
A) a steroid
B) cellulose
C) DNA
D) an enzyme
E) a contractile protein
Topic: Concepts 5.1-5.4
Skill: Comprehension
63) The element nitrogen is present in all of the
following except
A) proteins.
B) nucleic acids.
C) amino acids.
D) DNA.
E) monosaccharides.
Topic: Concepts 5.1-5.4
Skill: Knowledge
The following questions are based on the 15
molecules illustrated in Figure 5.8. Each molecule
may be used once, more than once, or not at all.
Figure 5.8
64) Which of the following molecules are
structural isomers?
A) 1 and 4
B) 5 and 14
C) 6 and 12
D) 12 and 13
E) 14 and 15
Topic: Concept 5.2
Skill: Comprehension
65) Which of the following combinations could be
linked together to form a nucleotide?
A) 1, 2, and 11
B) 3, 7, and 8
C) 5, 9, and 10
D) 11, 12, and 13
E) 12, 14, and 15
Topic: Concept 5.5
Skill: Comprehension
66) Which of the following molecules contain(s)
an aldehyde type of carbonyl functional group?
A) 1
B) 4
C) 8
D) 10
E) 1 and 4
Topic: Concept 5.2
Skill: Comprehension
67) Which of the following molecules is (are) a
carbohydrate?
A) 1 and 4
B) 6
C) 12
D) 5 and 14
E) all of the above
Topic: Concept 5.2
Skill: Comprehension
68) Which of the following molecules is a
saturated fatty acid?
A) 1
B) 5
C) 6
D) 8
E) 9
Topic: Concept 5.3
Skill: Knowledge
69) Which of the following molecules is a purine
type of nitrogenous base?
A) 2
B) 3
C) 5
D) 12
E) 13
Topic: Concept 5.5
Skill: Knowledge
70) Which of the following molecules act as
building blocks (monomers) of polypeptides?
A) 1, 4, and 6
B) 2, 7, and 8
C) 7, 8, and 13
D) 11, 12, and 13
E) 12, 13, and 15
Topic: Concept 5.4
Skill: Knowledge
71) Which of the following molecules is an amino
acid with a hydrophobic R group or side chain?
A) 3
B) 5
C) 7
D) 8
E) 12
Topic: Concept 5.4
Skill: Comprehension
72) Which of the following molecules could be
joined together by a peptide bond as a result of a
dehydration reaction?
A) 2 and 3
B) 3 and 7
C) 7 and 8
D) 8 and 9
E) 12 and 13
Topic: Concept 5.4
Skill: Comprehension
73) A fat (or triacylglycerol) would be formed as a
result of a dehydration reaction between
A) one molecule of 9 and three molecules of 10.
B) three molecules of 9 and one molecule of 10.
C) one molecule of 5 and three molecules of 9.
D) three molecules of 5 and one molecule of 9.
E) one molecule of 5 and three molecules of 10.
Topic: Concept 5.3
Skill: Comprehension
74) Which of the following molecules could be
joined together by a phosphodiester type of
covalent bond?
A) 3 and 4
B) 3 and 8
C) 6 and 15
D) 11 and 12
E) 11 and 13
Topic: Concept 5.3
Skill: Comprehension
75) Which of the following molecules is the
pentose sugar found in RNA?
A) 1
B) 4
C) 6
D) 12
E) 13
Topic: Concept 5.5
Skill: Knowledge
76) Which of the following molecules contains a
glycosidic linkage type of covalent bond?
A) 4
B) 6
C) 12
D) 13
E) 15
Topic: Concept 5.2
Skill: Comprehension
77) Which of the following molecules has (have) a
functional group that frequently is involved in
maintaining the tertiary structure of a protein?
A) 2
B) 3
C) 9
D) 11
E) 9 and 11
Answer: A
Topic: Concept 5.4
Skill: Comprehension
78) Which of the following molecules consists of a
hydrophilic "head" region and a hydrophobic "tail"
region?
A) 2
B) 5
C) 7
D) 9
E) 11
Topic: Concept 5.3
Skill: Knowledge
79) Which of the following statements is false?
A) 1 and 4 could be joined together by a glycosidic
linkage to form a disaccharide.
B) 9 and 10 could be joined together by ester
bonds to form a triacylglycerol.
C) 2 and 7 could be joined together to form a short
peptide.
D) 2, 7, and 8 could be joined together to form a
short peptide.
E) 14 and 15 could be joined together to form a
polypeptide.
Topic: Concepts 5.2-5.4
Skill: Comprehension
Media Activity Questions
80) Carbohydrates generally have a molecular
formula
A) that includes a -SH group.
B) in which carbon, hydrogen, and oxygen are
present in a ratio of 1:2:1.
C) that includes a -NH2 group.
D) that includes at least one hydrocarbon tail.
E) in which carbon, hydrogen, and oxygen are
present in a 2:1:2 ratio.
Answer: B
Topic: Web/CD Activity: Carbohydrates
81) A function of cholesterol that does not harm
health is its role
A) in calcium and phosphate metabolism.
B) as a component of animal cell membranes.
C) as the primary female sex hormone.
D) as the primary male sex hormone.
E) None of the above; all of cholesterol's effects on
the body are harmful.
Answer: B
Topic: Web/CD Activity: Lipids
82) Which of these does not contain a structural
protein?
A) muscles
B) tendons
C) ovalbumin
D) spider silk
E) ligaments
Topic: Web/CD Activity: Protein Functions
83) The primary structure of a protein is
A) an α helix or a pleated sheet.
B) the amino acid sequence of the polypeptide
chain.
C) composed of two or more polypeptide chains.
D) maintained by hydrogen bonds.
E) irregular folding.
Topic: Web/CD Activity: Protein Structure
84) Which of these is a difference between DNA
and RNA?
A) RNA is double-stranded; DNA is singlestranded.
B) DNA is found in the nucleus; RNA is never
found in the nucleus.
C) In DNA, adenine pairs with guanine; in RNA,
adenine pairs with thymine.
D) DNA contains thymine; RNA contains uracil.
E) DNA consists of five different nucleotides; RNA
consists of four different nucleotides.
Topic: Web/CD Activity: Nucleic Acid Structure
Self-Quiz Questions
85) Which term includes all others in the list?
A) monosaccharide
B) disaccharide
C) starch
D) carbohydrate
E) polysaccharide
86) The molecular formula for glucose is C6H12O6.
What would be the molecular formula for a
polymer made by linking ten glucose molecules
together by dehydration reactions?
A) C60H120O60
B) C60H12O6
C) C60H102O51
D) C60H100O50
E) C60H111O51
87) The enzyme amylase can break glycosidic
linkages between glucose monomers only if the
monomers are the α form. Which of the following
could amylase break down? (Choose all that
apply.)
A) cellulose
B) chitin
C) glycogen
D) starch
E) amylopectin
88) Choose the pair of terms that correctly
completes this sentence:
Nucleotides are to ________ as ________ are to
proteins.
A) nucleic acids; amino acids
B) amino acids; polypeptides
C) glycosidic linkages; polypeptide linkages
D) genes; enzymes
E) polymers; polypeptides
89) Which of the following statements concerning
unsaturated fats is true?
A) They are more common in animals than in
plants.
B) They have double bonds in the carbon chains of
their fatty acids.
C) They generally solidify at room temperature.
D) They contain more hydrogen than saturated
fats having the same number of carbon atoms.
E) They have fewer fatty acid molecules per fat
molecule.
90) The structural level of a protein least affected
by a disruption in hydrogen bonding is the
A) primary level.
B) secondary level.
C) tertiary level.
D) quaternary level.
E) All structural levels are equally affected.
91) Which of the following pairs of base
sequences could form a short stretch of a normal
double helix of DNA?
A) 5'-purine-pyrimidine-purine-pyrimidine-3'
with 3'-purine-pyrimidine-purine-pyrimidine-5'
B) 5'-A-G-C-T-3' with 5'-T-C-G-A-3'
C) 5'-G-C-G-C-3' with 5'-T-A-T-A-3'
D) 5'-A-T-G-C-3' with 5'-G-C-A-T-3'
E) A, B, and D are all correct.
92) Enzymes that break down DNA catalyze the
hydrolysis of the covalent bonds that join
nucleotides together. What would happen to DNA
molecules treated with these enzymes?
A) The two strands of the double helix would
separate.
B) The phosphodiester bonds between
deoxyribose sugars would be broken.
C) The purines would be separated from the
deoxyribose sugars.
D) The pyrimidines would be separated from the
deoxyribose sugars.
E) All bases would be separated from the
deoxyribose sugars.
93) Which of the following is not a protein?
A) hemoglobin
B) cholesterol
C) an antibody
D) an enzyme
E) insulin
94) Which of the following statements about the
5' end of a polynucleotide strand is correct?
A) The 5' end has a hydroxyl group.
B) The 5' end has a phosphate group.
C) The 5' end is identical to the 3' end.
D) The 5' end is antiparallel to the 3' end.
E) The 5' end is the fifth position on one of the
nitrogenous bases.
16) Which of the following is true regarding
deoxyribonucleic acid (DNA)?
A) Each deoxyribonucleic acid molecule is
composed of two long chains of nucleotides
arranged in a double helix.
B) Genes are composed of deoxyribonucleic acid.
C) DNA is composed of chemical building blocks
called nucleotides.
D) Only A and C are correct.
E) A, B, and C are correct.
Topic: Concept 1.1
Skill: Knowledge
17) What are the basic "building blocks" of
deoxyribonucleic acid (DNA)?
A) 100,000 different kinds of proteins
B) 26 different kinds of chromosomes
C) 20 different kinds of amino acids
D) 4 different kinds of nucleotides
E) 3 different kinds of genomes
Topic: Concept 1.1
Skill: Knowledge
18) Which of the following types of cells utilize
deoxyribonucleic acid (DNA) as their genetic
material?
A) animal
B) plant
C) archaea
D) A and B only
E) A, B, and C
Topic: Concept 1.1
Skill: Comprehension
21) In order to understand the chemical basis of
inheritance, one must understand the molecular
structure of DNA. This is an example of the
application of ________ to the study of biology.
A) evolution
B) emergent properties
C) reductionism
D) the cell theory
E) feedback regulation
Topic: Concept 1.2
Skill: Comprehension
22) The chemical reactions within cells are
regulated by organic catalysts called
A) feedback activators.
B) feedback inhibitors.
C) enzymes.
D) metabolites.
E) nutrients.
Topic: Concept 1.2
Skill: Knowledge
23) Once labor begins in childbirth, contractions
increase in intensity and frequency until delivery.
The increasing labor contractions of childbirth are
an example of
A) a bioinformatic system.
B) positive feedback.
C) negative feedback.
D) feedback inhibition.
E) both C and D
Topic: Concept 1.2
Skill: Comprehension
24) When blood glucose level rises, the pancreas
secretes insulin, and as a result blood glucose level
declines. When blood glucose level is low, the
pancreas secretes glucagon, and as a result blood
glucose level rises. Such regulation of blood
glucose level is the result of
A) catalytic feedback.
B) positive feedback.
C) negative feedback.
D) bioinformatic regulation.
E) both A and B
Topic: Concept 1.2
Skill: Comprehension
Metabolism & Enzymes
1) Which of the following describe(s) some aspect
of metabolism?
A) synthesis of macromolecules
B) breakdown of macromolecules
C) control of enzyme activity
D) A and B only
E) A, B, and C
Topic: Concept 8.1
Skill: Knowledge
2) Which term most precisely describes the
cellular process of breaking down large molecules
into smaller ones?
A) catalysis
B) metabolism
C) anabolism
D) dehydration
E) catabolism
Topic: Concept 8.1
Skill: Knowledge
3) Which of the following statements correctly
describe(s) catabolic pathways?
A) They do not depend on enzymes.
B) They consume energy to build up polymers
from monomers.
C) They release energy as they degrade polymers
to monomers.
D) They lead to the synthesis of catabolic
compounds.
E) both A and B
Topic: Concept 8.1
Skill: Knowledge
4) Which of the following is (are) true for anabolic
pathways?
A) They do not depend on enzymes.
B) They are highly regulated sequences of
chemical reactions.
C) They consume energy to build up polymers
from monomers.
D) They release energy as they degrade polymers
to monomers.
E) both B and C
Topic: Concept 8.1
Skill: Knowledge
5) Which of the following is a statement of the
first law of thermodynamics?
A) Energy cannot be created or destroyed.
B) The entropy of the universe is decreasing.
C) The entropy of the universe is constant.
D) Kinetic energy is stored energy that results
from the specific arrangement of matter.
E) Energy cannot be transferred or transformed.
Topic: Concept 8.1
Skill: Knowledge
6) The first law of thermodynamics states that
energy can be neither created nor destroyed. For
living organisms, which of the following is an
important consequence of the first law?
A) The energy content of an organism is constant.
B) The organism ultimately must obtain all of the
necessary energy for life from its environment.
C) The entropy of an organism decreases with
time as the organism grows in complexity.
D) Organisms are unable to transform energy.
E) Life does not obey the first law of
thermodynamics.
Topic: Concept 8.1
Skill: Application
7) According to the first law of thermodynamics,
A) the universe loses energy because of heat
production.
B) systems rich in energy are intrinsically
unstable and will give up energy with time.
C) energy can be neither created nor destroyed.
D) A and B only
E) A, B, and C
Topic: Concept 8.1
Skill: Comprehension
8) Living organisms increase in complexity as
they grow, resulting in a decrease in the entropy
of an organism. How does this relate to the
second law of thermodynamics?
A) Living organisms do not obey the second law of
thermodynamics, which states that entropy must
increase with time.
B) Life obeys the second law of thermodynamics
because the decrease in entropy as the organism
grows is balanced by an increase in the entropy of
the universe.
C) Living organisms do not follow the laws of
thermodynamics.
D) As a consequence of growing, organisms create
more disorder in their environment than the
decrease in entropy associated with their growth.
E) Living organisms are able to transform energy
into entropy.
Topic: Concept 8.1
Skill: Application
9) Which of the following statements about
metabolism is incorrect?
A) Metabolism is an emergent property of life at
the level of organisms.
B) Metabolism manages the utilization of
materials and energy resources.
C) The uptake of water associated with the
hydrolysis of biological polymers is part of
metabolism.
D) Metabolism depends on a constant supply of
energy.
E) None of these statements about metabolism is
incorrect.
Topic: Concept 8.1
Skill: Comprehension
10) Whenever energy is transformed, there is
always an increase in the
A) free energy of the system.
B) free energy of the universe.
C) entropy of the system.
D) entropy of the universe.
E) enthalpy of the universe.
Topic: Concept 8.1
Skill: Comprehension
11) Which of the following statements is a logical
consequence of the second law of
thermodynamics?
A) If the entropy of a system increases, there must
be a corresponding decrease in the entropy of the
universe.
B) If there is an increase in the energy of a system,
there must be a corresponding decrease in the
energy of the rest of the universe.
C) Every energy transfer requires activation
energy from the environment.
D) Every chemical reaction must increase the total
entropy of the universe.
E) Energy can be transferred or transformed, but
it cannot be created or destroyed.
Topic: Concept 8.1
Skill: Comprehension
12) Which of the following statements correctly
describe(s) some aspect of energy in living
organisms?
A) Living organisms can convert energy among
several different forms.
B) Living organisms can use energy to do work.
C) Organisms expend energy in order to decrease
their entropy
D) A and B only
E) A, B, and C
Topic: Concept 8.1
Skill: Comprehension
13) Which of the following statements is not
representative of the second law of
thermodynamics?
A) Conversion of energy from one form to another
is always accompanied by some loss of free
energy.
B) Heat represents a form of energy that cannot be
used by most organisms to do work.
C) Without an input of energy, organisms would
tend towards increasing entropy.
D) Cells require a constant input of energy to
maintain their high level of organization.
E) Every energy transformation by a cell
decreases the entropy of the universe.
Topic: Concept 8.1
Skill: Comprehension
16) According to the second law of
thermodynamics, which of the following
statements is incorrect?
A) The synthesis of large molecules from small
molecules is exergonic.
B) Earth is an open system.
C) Life exists at the expense of energy derived
from its environment.
D) A living cell can never function as a closed
system.
E) Every chemical reaction in a cell results in a
loss of free energy.
Topic: Concept 8.1
Skill: Comprehension
17) The organization of organisms has become
increasingly complex with time. This statement
A) is consistent with the second law of
thermodynamics.
B) requires that due to evolution, the entropy of
the universe increased.
C) is based on the fact that organisms function as
closed systems.
D) A and B only
E) A, B, and C
Topic: Concept 8.1
Skill: Comprehension
18) The mathematical expression for the change
in free energy of a system is: ΔG = ΔH - TΔS.
Which of the following is (are) incorrect?
A) ΔS is the change in entropy, a measure of
randomness.
B) ΔH is the change in enthalpy, the energy
available to do work.
C) ΔG is the change in free energy.
D) T is the absolute temperature.
E) both A and B
Topic: Concept 8.2
Skill: Knowledge
19) What is the change in free energy of a system
at chemical equilibrium?
A) slightly increasing
B) greatly increasing
C) slightly decreasing
D) greatly decreasing
E) no net change
Topic: Concept 8.2
Skill: Knowledge
20) Which of the following is true for all exergonic
reactions?
A) The products have more total energy than the
reactants.
B) The reaction proceeds with a net release of free
energy.
C) Some reactants will be converted to products.
D) A net input of energy from the surroundings is
required for the reactions to proceed.
E) The reactions are nonspontaneous.
Topic: Concept 8.2
Skill: Comprehension
21) Chemical equilibrium is relatively rare in
living cells. Which of the following could be an
example of a reaction at chemical equilibrium in a
cell?
A) a reaction in which the free energy at
equilibrium is higher than the energy content at
any point away from equilibrium
B) a chemical reaction in which the entropy
change in the reaction is just balanced by an
opposite entropy change in the cell's surroundings
C) an endergonic reaction in an active metabolic
pathway where the energy for that reaction is
supplied only by heat from the environment
D) a chemical reaction in which both the reactants
and products are only used in a metabolic
pathway that is completely inactive
E) There is no possibility of having chemical
equilibrium in any living cell.
Topic: Concept 8.2
Skill: Application
22) Which of the following shows the correct
changes in thermodynamic properties for a
chemical reaction in which amino acids are linked
to form a protein?
A) +ΔH, +ΔS, +ΔG
B) +ΔH, -ΔS, -ΔG
C) +ΔH, -ΔS, +ΔG
D) -ΔH, -ΔS, +ΔG
E) -ΔH, +ΔS, +ΔG
Topic: Concept 8.2
Skill: Comprehension
23) When glucose monomers are joined together
by glycosidic linkages to form a cellulose polymer,
the changes in free energy, total energy, and
entropy are as follows:
A) +ΔG, +ΔH, +ΔS
B) +ΔG, +ΔH, -ΔS
C) +ΔG, -ΔH, -ΔS
D) -ΔG, +ΔH, +ΔS
E) -ΔG, -ΔH, -ΔS
Topic: Concept 8.2
Skill: Comprehension
24) A chemical reaction that has a positive ΔG is
correctly described as
A) endergonic.
B) endothermic.
C) enthalpic.
D) spontaneous.
E) exothermic.
Topic: Concept 8.2
Skill: Knowledge
31) What term is used to describe the transfer of
free energy from catabolic pathways to anabolic
pathways?
A) feedback regulation
B) bioenergetics
C) energy coupling
D) entropy
E) cooperativity
Topic: Concept 8.3
Skill: Knowledge
32) Which of the following statements is true
concerning catabolic pathways?
A) They combine molecules into more energy-rich
molecules.
B) They are usually coupled with anabolic
pathways to which they supply energy in the form
of ATP.
C) They are endergonic.
D) They are spontaneous and do not need enzyme
catalysis.
E) They build up complex molecules such as
protein from simpler compounds.
Topic: Concept 8.3
Skill: Comprehension
35) How can one increase the rate of a chemical
reaction?
A) Increase the activation energy needed.
B) Cool the reactants.
C) Decrease the concentration of the reactants.
D) Add a catalyst.
E) Increase the entropy of the reactants.
Topic: Concept 8.4
Skill: Comprehension
36) Sucrose is a disaccharide, composed of the
monosaccharides glucose and fructose. The
hydrolysis of sucrose by the enzyme sucrase
results in
A) bringing glucose and fructose together to form
sucrose.
B) the release of water from sucrose as the bond
between glucose and fructose is broken.
C) breaking the bond between glucose and
fructose and forming new bonds from the atoms
of water.
D) production of water from the sugar as bonds
are broken between the glucose monomers.
E) utilization of water as a covalent bond is
formed between glucose and fructose to form
sucrase.
Topic: Concept 8.4
Skill: Application
enzymes is true?
A) Enzymes decrease the free energy change of a
reaction.
B) Enzymes increase the rate of a reaction.
C) Enzymes change the direction of chemical
reactions.
D) Enzymes are permanently altered by the
reactions they catalyze.
E) Enzymes prevent changes in substrate
concentrations.
Topic: Concept 8.4
Skill: Knowledge
40) Which of the following is not true of enzymes?
A) Enzyme catalysis is dependent on the pH and
temperature of the reaction environment.
B) Enzyme catalysis is dependent on the threedimensional structure or conformation of the
enzyme.
C) Enzymes provide activation energy for the
reaction they catalyze.
D) Enzymes are composed primarily of protein,
but they may bind nonprotein cofactors.
E) Enzyme activity can be inhibited if the
enzyme's allosteric site is bound with a
noncompetitive inhibitor.
Topic: Concept 8.4
Skill: Knowledge
37) Reactants capable of interacting to form
products in a chemical reaction must first
overcome a thermodynamic barrier known as the
reaction's
A) entropy.
B) activation energy.
C) endothermic level.
D) heat content.
E) free-energy content.
Topic: Concept 8.4
Skill: Knowledge
41) An enzyme catalyzes a reaction by
A) supplying the energy to speed up a reaction.
B) lowering the energy of activation of a reaction.
C) lowering the ΔG of a reaction.
D) changing the equilibrium of a spontaneous
reaction.
E) increasing the amount of free energy of a
reaction.
Topic: Concept 8.4
Skill: Knowledge
38) A solution of starch at room temperature
does not readily decompose to form a solution of
simple sugars because
A) the starch solution has less free energy than the
sugar solution.
B) the hydrolysis of starch to sugar is endergonic.
C) the activation energy barrier for this reaction
cannot be surmounted.
D) starch cannot be hydrolyzed in the presence of
so much water.
E) starch hydrolysis is nonspontaneous.
Topic: Concept 8.4
Skill: Comprehension
42) Which of these statements regarding enzymes
is false?
A) Enzymes are proteins that function as catalysts.
B) Enzymes display specificity for certain
molecules with which they interact.
C) Enzymes provide activation energy for the
reactions they catalyze.
D) The activity of enzymes can be regulated by
other molecules.
E) An enzyme may be used many times over for a
specific reaction.
Topic: Concept 8.4
Skill: Knowledge
39) Which of the following statements regarding
43) During a laboratory experiment, you discover
that an enzyme-catalyzed reaction has a ΔG of -20
kcal/mol. If you double the amount of enzyme in
the reaction, what will be the ΔG for the new
reaction?
A) -40 kcal/mol
B) -20 kcal/mol
C) 0 kcal/mol
D) +20 kcal/mol
E) +40 kcal/mol
Topic: Concept 8.4
Skill: Comprehension
44) The active site of an enzyme is the region that
A) binds allosteric regulators of the enzyme.
B) is involved in the catalytic reaction of the
enzyme.
C) binds the products of the catalytic reaction.
D) is inhibited by the presence of a coenzyme or a
cofactor.
E) both A and B
Topic: Concept 8.4
Skill: Knowledge
45) According to the induced fit hypothesis of
enzyme catalysis, which of the following is
CORRECT?
A) The binding of the substrate depends on the
shape of the active site.
B) Some enzymes change their structure when
activators bind to the enzyme.
C) A competitive inhibitor can outcompete the
substrate for the active site.
D) The binding of the substrate changes the shape
of the enzyme's active site.
E) The active site creates a microenvironment
ideal for the reaction.
Topic: Concept 8.4
Skill: Comprehension
46) Many different things can alter enzyme
activity. Which of the following underlie all types
of enzyme regulation?
A) changes in the activation energy of the reaction
B) changes in the active site of the enzyme
C) changes in the free energy of the reaction
D) A and B only
E) A, B, and C
Topic: Concept 8.4
Skill: Application
Refer to Figure 8.1 to answer the following
questions.
Figure 8.1
47) Which curve represents the behavior of an
enzyme taken from a bacterium that lives in hot
springs at temperatures of 70°C or higher?
A) curve 1
B) curve 2
C) curve 3
D) curve 4
E) curve 5
Topic: Concept 8.4
Skill: Knowledge
48) Which curve was most likely generated from
analysis of an enzyme from a human stomach
where conditions are strongly acid?
A) curve 1
B) curve 2
C) curve 3
D) curve 4
E) curve 5
Topic: Concept 8.4
Skill: Knowledge
49) Which curve was most likely generated from
an enzyme that requires a cofactor?
A) curve 1
B) curve 2
C) curve 4
D) curve 5
E) It is not possible to determine whether an
enzyme requires a cofactor from these data.
Topic: Concept 8.4
Skill: Comprehension
50) As temperature decreases, the rate of an
enzyme-catalyzed reaction also decreases. Which
of the following explain(s) why this occurs?
A) Fewer substrates have sufficient energy to get
over the activation energy barrier.
B) Motion in the active site of the enzyme is
slowed, thus slowing the catalysis of the enzyme.
C) The motion of the substrate molecules
decreases, allowing them to bind more easily to
the active site.
D) A and B only
E) A, B, and C
Topic: Concept 8.4
Skill: Application
51) ATP is often an allosteric inhibitor of key
enzymes in catabolic pathways. Which of the
following statements is inconsistent with the role
of ATP?
A) ATP couples energy production in catabolic
pathways to energy demand in anabolic pathways.
B) When ATP levels are high in the cell, it is an
indication that energy supply from catabolic
reactions exceeds energy demand by anabolic
reactions.
C) The binding of ATP to allosteric sites on
enzymes of the catabolic pathway decreases the
production of ATP by the pathway.
D) Increasing availability of ATP increases the
energy available to drive endergonic reactions.
E) When ATP levels are low in the cell, there is no
inhibition of the catabolic pathway and ATP
production is at a maximum.
Topic: Concept 8.4
Skill: Application
52) Increasing the substrate concentration in an
enzymatic reaction could overcome which of the
following?
A) denaturization of the enzyme
B) allosteric inhibition
C) competitive inhibition
D) saturation of the enzyme activity
E) insufficient cofactors
Topic: Concept 8.4
Skill: Comprehension
53) What is a nonprotein "helper" of an enzyme
molecule called?
A) accessory enzyme
B) allosteric group
C) coenzyme
D) functional group
E) enzyme activator
Topic: Concept 8.4
Skill: Knowledge
54) Which of the following is true of enzymes?
A) Enzymes may require a nonprotein cofactor or
ion for catalysis to take place.
B) Enzyme function is reduced if the threedimensional structure or conformation of an
enzyme is altered.
C) Enzyme function is influenced by physical and
chemical environmental factors such as pH and
temperature.
D) Enzymes increase the rate of chemical reaction
by lowering activation energy barriers.
E) All of the above are true of enzymes.
Topic: Concept 8.4
Skill: Knowledge
55) Zinc, an essential trace element for most
organisms, is present in the active site of the
enzyme carboxypeptidase. The zinc most likely
functions as a(n)
A) competitive inhibitor of the enzyme.
B) noncompetitive inhibitor of the enzyme.
C) allosteric activator of the enzyme.
D) cofactor necessary for enzyme activity.
E) coenzyme derived from a vitamin.
Topic: Concept 8.4
Skill: Knowledge
56) Consider the following: Succinate
dehydrogenase catalyzes the conversion of
succinate to fumarate. The reaction is inhibited by
malonic acid, which resembles succinate but
cannot be acted upon by succinate dehydrogenase.
Increasing the ratio of succinate to malonic acid
reduces the inhibitory effect of malonic acid.
Which of the following is correct?
A) Succinate dehydrogenase is the enzyme, and
fumarate is the substrate.
B) Succinate dehydrogenase is the enzyme, and
malonic acid is the substrate.
C) Succinate is the substrate, and fumarate is the
product.
D) Fumarate is the product, and malonic acid is a
noncompetitive inhibitor.
E) Malonic acid is the product, and fumarate is a
competitive inhibitor.
Topic: Concept 8.4
Skill: Comprehension
The following questions are based on the reaction A
+ B → C + D shown in Figure 8.2
C) positive ΔG, exergonic
D) negative ΔG, endergonic
E) ΔG of zero, chemical equilibrium
Topic: Concept 8.4
Skill: Comprehension
61) Which of the following represents the
difference between the free-energy content of the
reaction and the free-energy content of the
products?
A) a
B) b
C) c
D) d
E) e
Topic: Concept 8.4
Skill: Knowledge
Figure 8.2
57) Which of the following terms best describes
the reaction?
A) endergonic
B) exergonic
C) anabolic
D) allosteric
E) nonspontaneous
Topic: Concept 8.4
Skill: Knowledge
58) Which of the following represents the ΔG of
the reaction?
A) a
B) b
C) c
D) d
E) e
Topic: Concept 8.4
Skill: Knowledge
59) Which of the following would be the same in
an enzyme-catalyzed or noncatalyzed reaction?
A) a
B) b
C) c
D) d
E) e
Topic: Concept 8.4
Skill: Comprehension
60) Which of the following bests describes the
reaction?
A) negative ΔG, spontaneous
B) positive ΔG, nonspontaneous
62) Which of the following represents the
activation energy required for the enzymecatalyzed reaction?
A) a
B) b
C) c
D) d
E) e
Topic: Concept 8.4
Skill: Comprehension
63) Which of the following represents the
activation energy required for a noncatalyzed
reaction?
A) a
B) b
C) c
D) d
E) e
Topic: Concept 8.4
Skill: Knowledge
64) Which best describes the reaction?
A) The amount of free energy initially present in
the reactants is indicated by "a."
B) The amount of free energy present in the
products is indicated by "e."
C) The amount of free energy released as a result
of the noncatalyzed reaction is indicated by "c."
D) The amount of free energy released as a result
of the catalyzed reaction is indicated by "d."
E) The difference between "b" and "c" is the
activation energy added by the presence of the
enzyme.
Topic: Concept 8.4
Skill: Comprehension
65) Assume that the reaction has a ΔG of -5.6
kcal/mol. Which of the following would be true?
A) The reaction could be coupled to power an
endergonic reaction with a ΔG of +6.2 kcal/mol.
B) The reaction could be coupled to power an
exergonic reaction with a ΔG of +8.8 kcal/mol.
C) The reaction would result in a decrease in
entropy (S) and an increase in the total energy
content (H) of the system.
D) The reaction would result in an increase in
entropy (S) and a decrease in the total energy
content (H) of the system.
E) The reaction would result in products (C + D)
with a greater free-energy content than in the
initial reactants (A + B).
Topic: Concept 8.4
Skill: Comprehension
The next questions are based on the following
information.
A series of enzymes catalyze the reaction
X→Y→Z→A. Product A binds to the enzyme that
converts X to Y at a position remote from its active
site. This binding decreases the activity of the
enzyme.
66) What is substance X?
A) a coenzyme
B) an allosteric inhibitor
C) a substrate
D) an intermediate
E) the product
Topic: Concept 8.5
Skill: Comprehension
67) Substance A functions as
A) a coenzyme.
B) an allosteric inhibitor.
C) the substrate.
D) an intermediate.
E) a competitive inhibitor.
Answer: B
Topic: Concept 8.5
Skill: Comprehension
68) The mechanism in which the end product of a
metabolic pathway inhibits an earlier step in the
pathway is known as
A) metabolic inhibition.
B) feedback inhibition.
C) allosteric inhibition.
D) noncooperative inhibition.
E) reversible inhibition.
Topic: Concept 8.5
Skill: Knowledge
69) The regulation of enzyme function is an
important aspect of cell metabolism. Which of the
following is least likely to be a mechanism for
enzyme regulation?
A) allosteric regulation
B) cooperativity
C) feedback inhibition
D) removing cofactors
E) reversible inhibition
Topic: Concept 8.5
Skill: Comprehension
70) Which of the following statements is true
regarding enzyme cooperativity?
A) A multi-enzyme complex contains all the
enzymes of a metabolic pathway.
B) A product of a pathway serves as a competitive
inhibitor of an early enzyme in the pathway.
C) A substrate molecule bound to an active site
affects the active site of several subunits.
D) Several substrate molecules can be catalyzed
by the same enzyme.
E) A substrate binds to an active site and inhibits
cooperation between enzymes in a pathway.
Topic: Concept 8.5
Skill: Knowledge
71) How does a non-competitive inhibitor
decrease the rate of an enzyme reaction?
A) by binding at the active site of the enzyme
B) by changing the structure of the enzyme
C) by changing the free energy change of the
reaction
D) by acting as a coenzyme for the reaction
E) by decreasing the activation energy of the
reaction
Topic: Concept 8.5
Skill: Knowledge
Use Figure 8.3 to answer the following questions.
Figure 8.3
72) Which of the following statements correctly
indicate(s) the role of ATP or ADP as an allosteric
regulator? Assume that the supply of energy for
cellular processes is adjusted to meet cellular
demand for energy.
A) ATP is an allosteric inhibitor of catabolic
pathways.
B) ADP is an allosteric activator of catabolic
pathways.
C) ATP is an allosteric activator of anabolic
pathways.
D) A and B only
E) A, B, and C
Topic: Concept 8.5
Skill: Application
73) An increase in the level of cellular ATP is
likely to occur under which of the following
conditions?
A) increased activity of catabolic pathways
B) decreased activity of anabolic pathways
C) allosteric inhibition of anabolic pathways
D) A and B only
E) A, B, and C
Topic: Concept 8.5
Skill: Comprehension