Module 2. General principles of metabolism
Test questions in text form
1. ______________ is a cosubstrate.
A. * Tetrahydrofolate.
B. NADH
C. Biotin
D. Thiamin pyrophosphate.
E. Pyridoxol phosphate
2. ________________ can bind to the free enzyme.
A. * A competitive inhibitor
B. A uncompetitive inhibitor
C. A non-competitive inhibitor
D. a and c
E. b and c
3. _________ is the coenzyme involved in decarboxylation reactions.
A. Tetrahydrofolate.
B. NADH
C. Biotin
D. Thiamin pyrophosphate.
E. * Pyridoxol phosphate.
4. _____________ alters the Vmax of an enzyme.
A. A competitive inhibitor
B. * A uncompetitive inhibitor
C. A non-competitive inhibitor
D. A and c
E. B and c
5. _____________ binds to the enzyme at sites other than the substrate binding site.
A. An allosteric inhibitor
B. * A uncompetitive inhibitor
C. A non-competitive inhibitor
D. A and c
E. All of the above
6. ____________________ is the term that describes a theoretical value achieved when all
enzyme substrate binding sites are occupied by the substrate.
A. Km
B. Kcat
C. Vmax
D. * kcat/ Km
E. mg
7. (k-1 + kcat)/k1 = _________.
A. Vmax
B. * Km
C. Kcat
D. Kcat/Km
E. All of the above
8. A catalyst can promote product formation during a chemical reaction by _____.
A. Lowering the activation energy barrier.
B. Stabilizing the transition state.
C. Positioning reactants in the correct orientation.
D. * Bringing reactants together.
E. All of the above
9. A catalyst can promote product formation during a chemical reaction by _____.
A. Lowering the activation energy barrier.
B. Stabilizing the transition state.
C. Positioning reactants in the correct orientation.
D. * Bringing reactants together.
E. All of the above
10. A column packed with the sieved particles are used in which of the following techniques
to separate smaller and larger protein molecules
A. Affinity chromatography
B. Electrophoresis
C. * Molecular exclusion chromatography
D. Selective adsorbtion
E. All of these
11. A competitive inhibitor binds to
A. Substrate
B. * Active site
C. Allosteric site
D. Enzyme-substrate complex
E. Coenxyme
12. A reaction is designated as exergonic rather than endergonic when ___________.
A. Activation energy exceeds net energy release
B. Activation energy is necessary
C. No kinetic energy is released
D. * The potential energy of the products is less than the potential energy of the
reactants
E. It absorbs more energy
13. A reversible inhibitor that can bind to either E alone or the ES complex is referred to as a
_____.
A. Competitive inhibitor.
B. * Non-competitive inhibitor
C. Uncompetitive inhibitor
D. Suicide inhibitor
E. Irreversible inhibitor
14. A reversible inhibitor that only binds to the ES complex is referred to as a _____.
A. Competitive inhibitor
B. Non-competitive inhibitor
C. Uncompetitive inhibitor
D. Suicide inhibitor
E. * Irreversible inhibitor
15. A thermodynamic pit occurs when
A. ES is not very stable
B. ES forms faster than it dissociates
C. * ES is highly stable
D. S is not bound tightly to an enzyme
E. S is positioned incorrectly to the enzyme
16. According to the second law of thermodynamics, which of the following is true?
A. The total amount of energy in the universe is constant.
B. Energy conversions increase the order in the universe.
C. The ordering of one system depends on the disordering of another.
D. The entropy of the universe is constantly decreasing.
E. * All reactions produce some heat.
17. Active holoenzymes are formed from ____________ in the presence of _________.
A. Cofactors; proteins
B. Proteins; cofactors
C. * Apoenzymes; cofactors
D. Apoenzymes; proteins
E. Apoenzymes; inactive holoenzymes
18. An allosteric inhibitor of an enzyme usually
A. Binds to the active site.
B. * Participates in feedback regulation.
C. Denatures the enzyme.
D. Causes the enzyme to work faster.
E. Is a hydrophobic compound.
19. An enzyme is said to be catalytically perfect when _______.
A. It has a large Km
B. It has a small kcat
C. * Its kcat/Km value is close to that of the diffusion limit
D. It has very high affinity for the transition state
E. All of the above
20. An enzyme is specific. This means
A. It has a certain amino acid sequence.
B. It is found only in a certain place.
C. It functions only under certain environmental conditions.
D. It speeds up a particular chemical reaction.
E. * It occurs in only one type of cell.
21. An update of Fischer's lock and key theory of enzyme specificity view the _______ as the
lock and _______ as the key.
A. Enzyme; substrate
B. Substrate; enzyme
C. * Enzyme; transition state
D. Transition state; enzyme
E. Substrate; transition state
22. By efektors can forward some substance, except:
A. Hormones
B. Mediators of the nervous system
C. Metals
D. Products of enzymatic reactions
E. * Vitamins
23. Ca++ or Mg++ are most likely to be part of ___________, while Zn++ or Fe++ are
present in _______________.
A. * Metal-activated enzymes; metalloenzymes
B. Metalloenzymes; metal-activated enzymes
C. Cofactors; coenzymes
D. Coenzymes; cofactors
E. Apoenzymes; holoenzymes
24. Conserved serine, histidine and aspartate residues are present in the catalytic center of all
serine proteases. Which of the following describes the role of the histidine residue in the
mechanism of this reaction?
A. * Covalent binding of acyl groups
B. Hydrophobic stabilization of the substrate
C. Proton transfer
D. Cation binding
E. Anion transport
25. Consider a hypothetical metabolic pathway for the synthesis of the amino acid arginine:
precursor A intermediate B arginine. Each reaction is catalyzed by a different enzyme.
This metabolic pathway is controlled by feedback inhibition with arginine inhibiting the
conversion of precursor A to intermediate B. In this case, arginine almost certainly acts
as a _____ of the first enzyme in the pathway.
A. * Substrate
B. Competitive inhibitor
C. Catalyst
D. Cofactor
E. None of the above
26. Covalent modifications that increase the activity of allosterically regulated enzymes do so
by ______________.
A. * Adding phosphate groups to essential amino acids in the active site
B. Causing the enzyme to fold into a more active configuration
C. Increasing the amount of total enzyme present
D. None of the above
E. All of the above
27. During allosteric, or feed back, inhibition
A. Transcription of mRNA specific for the enzymes involved in the pathway is
repressed by the pathway's end product.
B. Enzyme concentrations in the cell remain relatively constant.
C. * The pathway's end product represses the activity of the first enzyme in the
pathway
D. All of the above apply to feedback inhibition.
E. More than one of the above, but not all, apply to feedback inhibition.
28. During electrophoretic research of LDG in the blood serum found out predominance of
content of LDG1 and LDG2. Pathology of what organ does these information testify?
A. Lungs
B. * Heart
C. Liver
D. Musculs
E. Spleen
29. During enzyme repression
A. The pathway's end product represses the activity of the first enzyme in the
pathway.
B. B.Enzyme concentrations in the cell remain relatively constant.
C. Transcription of mRNA specific for the enzymes involved in the pathway is
repressed by the pathway's end product.
D. * More than one of the above, but not all, apply to feedback inhibition.
E. All of the above apply to feedback inhibition.
30. During feedback inhibition, the effector molecule binds to the enzyme's ___________
site
A. Permissive
B. Alternative
C. Allosteric
D. * Conformational
E. Active
31. Energy-requiring reactions can occur in biological systems because enzymes allow their
coupling to other reactions with:
A. The activation energy of the reaction is doubled.
B. The activation energy of the reaction is lowered.
C. It's optimal conditions for temperature of the enzyme are doubled.
D. * The shape of the enzyme molecule is changed.
E. All of above
32. Enzymes that are allosterically regulated ____________________.
A. Are multimeric proteins
B. * Possess regulatory and catalytic domains
C. Do not behave according to the Michaelis-Menton equation
D. All of the above
E. Are monomeric proteins
33. Enzymes:
A. Are composed primarily of polypeptides, which are polymers of amino acids.
B. * Can bind prosthetic groups such as metal ions that participate in enzyme
reactions.
C. Have defined structures.
D. Bind their substrates at active sites.
E. All statements are true.
34. Ethanol (CH3CH2OH) is the alcohol found in beverages. It is oxidized in the body to
acetaldehyde by the enzyme alcohol dehydrogenase. Methanol (CH3OH), also known as
wood alcohol, is converted to formaldehyde by the same enzyme. Acetaldehyde is toxic,
but formaldehyde is far more toxic to humans, which is why the ingestion of relatively
small amounts of methanol can cause blindness or death. One treatment for mild
methanol poisoning is the administration of ethanol. Why might a doctor choose this
treatment?
A. Ethanol must act as a competitive inhibitor for the alcohol dehydrogenase and
therefore slows the formation of formaldehyde.
B. Ethanol likely irreversibly binds to alcohol dehydrogenase which prevents the
formation of formaldehyde.
C. * The ethanol is likely an uncompetitive inhibitor and binds to a site other than
the active site of the enzyme.
D. The doctor has given up on the patient and administers ethanol for sedation
E. B and C
35. If it is known that the only two ionizable residues in the active site are both glutamates,
which conclusion can be drawn?
A. * The glutamates have different microenviroments which cause their pKa's to
differ.
B. One of the glutamates must be amidated.
C. Both glutamates have a pKa equal to 5.0.
D. Both glutamates are deprotonated during the reaction.
E. B and C
36. If the tertiary structure of an enzyme is changed _____.
A. * Its substrate may not fit properly in the active site
B. It will be missing one of its polypeptides
C. The helical coil will be stretched out
D. The product of the reaction will be a different molecule
E. Its substrate will bond covalently with the wrong part of the molecule
37. In a multienzyme complex the process of directly transferring a product of one reaction
to the next active site without allowing it to enter the bulk solvent is termed _______.
A. a ping-pong reaction
B. * metabolite channeling
C. the activity pathway
D. the sequential mode
E. All of the above
38. In a ping-pong reaction which does not occur?
A. One product is released before a second substrate is bound.
B. The enzyme covalently binds a portion of the first substrate.
C. * The enzyme is permanently converted to an altered form by the first substrate.
D. A group is transferred from one substrate to another.
E. All of the above
39. Izoenzymes differ between itself some physical and chemical properties, except:
A. Electrophoretic mobility
B. Molecular activity
C. Stability
D. * Present in different tissues
E. Difference their primary structure
40. Mg2+ is used as a(n) by metal activate enzymes that utilize negatively charged substrates
like ATP.
A. Metalloenzyme
B. * Activator ion
C. Prosthetic group
D. Co-substrate
E. Ingibitor ion
41. R-CH2OH + O2 > R-CHO + H2O2 which of the following types of enzymes catalyzes
this reaction
A. Dehydrogenase
B. Oxidase
C. * Peroxidase
D. Aldolase
E. Catalase
42. Some antibody molecules are enzymatic if they are formed against
A. Enzymes
B. Enzymes bound to other proteins
C. * Transition state analogs bound to other proteins
D. Transition state analogs
E. All of the above
43. Specificity of enzyms is conditioned by the following factors, except:
A. Conformation complementare
B. Electrostatic complementare
C. The feature structure of active center of enzyme
D. * The feature structure of allosteric center
E. Proteins nature
44. ?The active site of an enzyme differs from an antibody-antigen binding site in that the
enzyme active site
A. Contains modified amino acids
B. Catalyzes a chemical reaction
C. Is complementary to a specific ligand
D. * Contains amino acids without sidechains
E. None of the above are correct
45. The assumptions made in calculating the Michaelis-Menten Equation include
A. That the formation and decomposition of ES is the same for a period of time
B. That the concentration of the substrate is much greater than the concentration of E
C. That the value of k-2 can be ignored
D. * a, b and c
E. a and b
46. The catalytic triad of chymotrypsin and other serine proteases are
A. Three subunits of the enzyme.
B. Three adjacent amino acid residues which act to make serine a strong nucleophile.
C. * Three amino acid residues close enough together to make serine a strong
nucleophile.
D. Three enzymes with very similar structural features.
E. All of the above
47. The concentrations of enzymes is determined by using pseudo first-order conditions in
which
A. S concentration is kept the same and the rate is measured
B. E concentration is kept the same and the rate is measured
C. * S concentration is constant, E concentration varied and the rate is measured
D. E concentration is constant, S concentration varied and the rate is measured
E. All of the above
48. The data shown on the graph were obtained for a kinetic experiment. What type of
inhibition is it?
A. Competitive
B. Uncompetitive
C. * Noncompetitive
D. Irreversible
E. A and B
49. The enzyme has an active site which
A. Fits the substrate exactly
B. Fits the transition state
C. May contain hydrogen bonds which are covalent like
D. a and c
E. * b and c
50. The equilibrium constant for the reaction, glucose 6-phosphate + water T glucose +
phosphate, is 260. What can you conclude about this reaction:
A. It is a closed system
B. It never reached equilibrium.
C. Starting with glucose 6-phosphate, it is not spontaneous.
D. * At equilibrium, the concentration of glucose is much higher than the
concentrations of glucose 6-phosphate.
E. At equilibrium, the concentration of glucose is much higher than the
concentrations of phosphate
51. The mechanism of enzyme action is _____.
A. * To create an energy barrier between substrates
B. To lower the energy of the activation of a reaction
C. To change the direction of thermodynamic equilibrium
D. To change endergonic into exergonic reactions
E. To allow substrates to move more freely in solution
52. The Michaelis constant, Km, is
A. The maximum velocity that any given enzyme reaction can achieve
B. The substrate concentration which gives the best enzyme assay for an enzyme
reaction
C. * The substrate concentration when the reaction is half the way toward the
maximal velocity
D. The maximal velocity divided in half
E. All of the above
53. The rate of a second order reaction depends on the concentration of _________.
A. One substrate
B. * Two substrates
C. Three substrates
D. None of the above
E. Ten substrates
54. The result of a(n) __________ reaction is that energy is released. Energy must be added
for a(n) __________ reaction to proceed.
A. Enzyme catalyzed, non-spontaneous
B. * Exergonic, endergonic
C. Endergonic, spontaneous
D. Catalytic, non-catalytic
E. Oxidative, hydrolysis
55. The steady state assumption for Michaelis-Menton kinetics assumes that ______.
A. * The concentration of the ES complex is constant
B. The rate of ES formation is faster than the rate of ES disassociation
C. k1 = k-1= kcat
D. The concentration of the ES complex is increase
E. None of the above
56. The term ligase refers to a class of enzymes that catalyzes_________.
A. Oxidation reduction reactions
B. Reactions involving the transfer of a functional group from one molecule to
another
C. Hydrolytic cleavages
D. * Reactions where two molecules are joined together
E. All of the above
57. The time that is required for an enzyme to convert one substrate molecule into one
product molecule is
A. Km
B. kcat
C. 1/Km
D. * 1/kcat
E. 1 min
58. The Vmax of an enzyme changes when the enzyme is treated with a_____.
A. Competitive inhibitor
B. Uncompetitive inhibitor
C. Noncompetitive inhibitor
D. A and b
E. * B and c
59. Two curves showing the rate versus substrate concentration are shown below for an
enzyme-catalyzed reaction. One curve is for the reaction in the presence of substance X.
The other curve is for data in the absence of substance X. Examine the curves and tell
which statement below is false.
A. X is an activator of the enzyme.
B. The enzyme kinetics are non-Michaelis-Menton.
C. X is likely an allosteric modulator.
D. * X is a competitive inhibitor.
E. None of above
60. What shape would a graph of reaction velocity versus pH have for an enzyme that uses
both a proton donor and a proton acceptor during catalysis (both acid and base catalysis)?
A. Sigmoidal
B. Hyperbolic
C. Exponential
D. * Bell-shaped
E. Linear
61. When the concentration of a substrate inside a cell falls below the substrate concentration
at half maximal velocity,
A. ES is formed more easily
B. * ES dissociates to E + S
C. ES is closer to the ground state than to the transition state
D. E + S is in equilibrium with ES
E. The reaction will not proceed
62. When the rate of an enzymatic reaction is controlled by the amount of enzyme present,
which of the following factors controls enzyme levels?
A. Rates of transcription
B. Rates of translation
C. Rates of protein turnover
D. Rates of mRNA turnover
E. * All of the above
63. Which cofactor has the following properties: a) forms Schiff base, b) its precursor is
absorb dietarily as Vitamin B6, c) is required in a number of reactions in aminoacid
metabolism.
A. Thiamin pyrophosphate
B. Biotin
C. Lipoamide
D. * Pyridoxal phosphate
E. Nicotinamid
64. Which from the adopted enzymes can united in polienzymes complexes?
A. * Pyruvatdehydrogenase
B. Transketolase
C. Suktsinatdehydrogenase
D. Al'dolase
E. Glukos-6-phosphatase
65. Which is not a reason for metabolite channeling?
A. Protection of intermediates from degradation.
B. Increasing the overall rate of a reaction.
C. Producing locally high concentrations of intermediates.
D. * Ensuring the enzyme is properly regulated.
E. A and C
66. Which of the following are properties of a cosubstrate?
A. * They are covalently attached to the active site of the enzyme.
B. Once they have been involved in an enzymatic reaction require a separate
unrelated enzymatic reaction to be converted to their original state.
C. They remain unchanged over the course of a reaction.
D. B and c
E. All of the above.
67. Which of the following coenzymes forms a Schiff’s base during catalysis?
A. NADH
B. Thiamin pyrophosphate
C. Lipoamide
D. * Pyridoxal phosphate
E. Coenzyme A
68. Which of the following cofactors is able to bind CO2 and transfer it to an appropriate
acceptor molecule?
A. * Pyridoxal phosphate
B. Biotin
C. Thiamin pyrophophosphate
D. Lipoamide
E. NAD(P)H
69. Which of the following common drugs is not a specific enzyme inhibitor?
A. Methotrexate
B. Penicillin
C. * Sulfonilamide
D. Iodine
E. Viagra
70. Which of the following factors contribute to the elevation of the ground state energy of a
substrate once it binds to the enzyme?
A. Less favorable entrophy values
B. Favorable charge-charge interactions
C. * Interactions between polar functional groups on the substrate surface and
hydrophobic amino acids in the enzyme’s substrate binding site.
D. A and b
E. A and c
71. Which of the following is characteristic of an enzyme catalyst?
A. It positions reactants in the correct orientation
B. It lowers the activation energy barrier
C. It binds the transition state tighter than the substrate
D. * Are affected by temperature
E. All of the above
72. Which of the following is true for a covalent catalysis based enzymatic mechanism.
A. A covalently modified enzyme intermediate is involved.
B. The enzyme undergoes a sequential reaction.
C. The enzyme undergoes a ping pong reaction.
D. a and b
E. * a and c
73. Which of the following kinetic parameters best describes how well suited a specific
compound functions as a substrate for a particular enzyme?
A. Km
B. Vmax
C. kcat
D. * kcat/Km
E. kg
74. Which of the following reversible inhibitors alter an enzyme’s function by increasing the
Vmax of the enzyme?
A. Competitive inhibitor
B. Non-competitive inhibitor
C. Uncompetitive inhibitor
D. * None of the above
E. Over-competitive inhibitor
75. Which of the following statements about reaction rate is NOT true?
A. Reaction rate is the speed at which the reaction proceeds toward equilibrium.
B. Reaction rate is governed by the energy barrier between reactions and products
C. * Enzymes can accelerate the rate of a reaction.
D. Reaction rates are not sensitive to temperature.
E. None of these.
76. Which property is common for enzymes and inorganic catalysts?
A. Specificity
B. Sensitiveness to the action of extraneous factors
C. * Catalysis only thermodynamics possible reactions
D. Dependence from рН and temperatures
E. High catalytic activity
77. Which statement is false about allosteric regulation?
A. * It is usually the mode of regulation for the last step in reaction pathways since
this step produces the final product.
B. Cellular response is faster with allosteric control than by controlling enzyme
concentration in the cell.
C. The regulation usually is important to the conservation of energy and materials in
cells.
D. Allosteric modulators bind non-covalently at sites other than the active site and
induce conformational changes in the enzyme.
E. B and C
78. Which statement is false about covalent modification?
A. It is reversible.
B. It is slightly slower than allosteric regulation.
C. * It usually uses the same enzyme for activation and inactivation.
D. All of the above
E. A and B
79. Which statement is false about regulatory enzymes that are controlled allosterically?
A. * They are always less active when a modulator is bound to them.
B. They are often larger than other enzymes.
C. They have more than one binding site.
D. They often catalyze the first step in a reaction pathway.
E. They have more than two binding site.
80. Why does heating interfere with the activity of an enzyme?
A. It kills the enzyme.
B. It changes the enzyme’s shape.
C. It decreases the energy of substrate molecules.
D. * It causes the enzyme to break up.
E. It decreases the chance that the enzyme will meet a substrate molecule.
81. Zymogens are inactive enzyme precursors which are made active by
A. A change in structure
B. Selective proteolysis
C. Secretion to new types of cells
D. a and b
E. * a, b and c
82. Which element is present in maltase, but not in maltose?
A. Carbon
B. Hydrogen
C. Oxygen
D. * Nitrogen
E. None of the above
83. _________ is the coenzyme involved in decarboxylation reactions.
A. Tetrahydrofolate.
B. NADH
C. Biotin
D. Thiamin pyrophosphate.
E. * Pyridoxol phosphate.
84. A certain enzyme will hydrolyze egg white but not starch. Which statement best explains
this observation?
A. Starch molecules are too large to be hydrolyzed.
B. * Enzyme molecules are specific in their actions.
C. Egg white acts as a coenzyme for hydrolysis.
D. Starch is composed of amino acids.
E. Egg white acts as a inhibitor for hydrolysis.
85. A coenzyme is
A. An ionic cofactor that interacts with an enzyme to allow it to work.
B. A protein cofactor that interacts with an enzyme to allow it to work.
C. * A nonprotein organic cofactor that interacts with an enzyme to allow it to work.
D. An ionic cofactor that interacts with an enzyme to inhibit it.
E. A protein cofactor that interacts with an enzyme to inhibit it.
86. A competitive inhibitor binds to
A. Substrate
B. * Active site
C. Allosteric site
D. Enzyme-substrate complex
E. Coenxyme
87. A competitive inhibitor of an enzyme is usually:
A. A highly reactive compound.
B. A metal ion such as Hg2+ or Pb2+.
C. * Structurally similar to the substrate.
D. Water insoluble.
E. A poison.
88. A laboratory test allows assuming the presence of inflammatory process in a liver. The
increase of what enzyme in blood will confirm this?
A. LDH 1,2
B. * Carbamoil phosphate ornitin transferase
C. AsAT
D. Creatin phosphokinase
E. Aldolase
89. A newborn suffers convulsions after meal, touches. It is discovered that reason of disease
is a defect of pyridine dependent enzyme which forms GABA in a brain. Name this
enzyme.
A. * Glutamate decarboxylase
B. Amino transferase
C. Cistationin synthase
D. Kinurinase
E. Ribonuclease
90. A phenylketonuria appears as a result of innate absence of enzyme:
A. Tirosin oxidase
B. * Phenylalanin-4-hydroxylase
C. Oxidase of gomogentisic acid
D. Amino oxidase
E. Xantine oxidase
91. A reversible inhibitor that can bind to either E alone or the ES complex is referred to as a
_____.
A. Competitive inhibitor.
B. * Non-competitive inhibitor
C. Uncompetitive inhibitor
D. Suicide inhibitor
E. Irreversible inhibitor
92. A reversible inhibitor that only binds to the ES complex is referred to as a _____.
A. Competitive inhibitor
B. Non-competitive inhibitor
C. Uncompetitive inhibitor
D. Suicide inhibitor
E. * Irreversible inhibitor
93. A substance that is Not a coenzyme is
A. * ATP
B. NAD+
C. NADPH
D. FAD
E. Pyrydoxal phosphate
94. Abzymes are
A. Immuno globulins
B. Isozymes
C. * Allosteric enzymes
D. Catalytic antibodies
E. Vitamins
95. According to the international classification there are six classes of enzymes in such
order:
A. Oxidoreductases, hydrolyses, ligases, lyases, transferases, isomerases.
B. Transferases, hydrolyses, oxidoreductase, isomerases, lyases, ligases.
C. Hydrolyses, oxidoreductase, transferases, lyases, isomerases, ligases.
D. Oxidoreductase, transferases, hydrolyses, isomerases, ligases, lyases.
E. * Oxidoreductase, transferases, hydrolyses, lyases, isomerases, ligases.
96. Active trypsin formation by the action of enteropeptidase can be viewed as the master
activation step because
A. It occurs first
B. It can activate its own zymogen
C. * Trypsin activates other pancreatic zymogens
D. A and B
E. A, B and C
97. Acyl-group-transfer reactions often involve which coenzyme?
A. * Coenzyme A
B. NAD+
C. Cytochrome c
D. All of the above
E. None of the above
98. Aldolase is classified as a(n)
A. Oxidoreductase
B. Transferase
C. Hydrolase
D. * Lyase
E. Isomerase
99. Allosteric centers serve as:
A. * The place of influence on the enzyme different regulator factors
B. The place of enzyme and substrate relation
C. Catalytic area
D. Contact area
E. All of the above
100.
Allosteric enzymes _____________.
A. Usually have quaternary structure.
B. Do not behave according to Michaelis-Menten kinetics.
C. * Bind allosteric modulators at sites not associated with substrate binding.
D. Often have separate catalytic and regulator domains.
E. All of the above.
101.
Among the below named enzymes a metalloprotein is following:
A. * Carboanhydrase
B. Lactate dehydrogenase
C. Pepsin
D. Phosphatase
E. Amylase
102.
Among the enzymes of antioxide defense of an organism directly decomposes the
toxic hydrogen peroxide:
A. * Catalase
B. Superoxyde dismutase
C. Glutation peroxidase
D. Glutation reductase
E. Xantine oxidase.
103.
An enzyme is generally named by adding ____ to the end of the name of the
_____.
A. "-ose". cell in which it is found
B. "-ase". cell in which it is found
C. "-ose". substrate
D. * "-ase". substrate
E. "-ase". coenzyme
104.
An enzyme that catalyzes conversions of L-sugars to D-sugars is called an
A. Lyase
B. Hydrolase
C. Synthetase
D. Synthase
E. * Isomerase
105.
An enzyme that hydrolyzes protein will not act upon starch. This fact is an
indication that enzymes are
A. Hydrolytic
B. * Specific
C. Catalytic
D. Synthetic
E. Universal
106.
An increase of acetaldehyde in blood is causes disgust of an alcohol. What
preparation - the inhibitor of aldehyde dehydrogenase is used in medical practice for the
prophylaxis of alcoholism?
A. Ethanol.
B. * Teturam.
C. Trasilol
D. Aldehyde.
E. Methanol.
107.
An inhibitor binds to a site other than the active site of the enzyme. Which
statement below correlates with this observation?
A. It must be a competitive inhibitor.
B. The inhibition must be irreversible.
C. * It could be noncompetitive or uncompetitive inhibition.
D. It could be irreversible, competitive, noncompetitive or uncompetitive. The data
do not relate to the type of inhibition.
E. None of above
108.
An inhibitor that changes the overall shape and chemistry of an enzyme is known
as a(n)
A.
B.
C.
D.
E.
* allosteric inhibitor
competitive inhibitor
steric inhibitor
noncompetitive inhibitor
None of the above.
109.
An ion commonly found in metalloenzymes and which can undergo reversible
oxidation and reduction is
A. Ca++
B. Mg++
C. S=
D. * Fe++
E. All of the above
110.
An uncompetitive inhibitor of an enzyme catalyzed reaction
A. * Binds to the Michaelis complex (ES).
B. Decreases Vmax.
C. Is without effect at saturating substrate concentration.
D. Can actually increase reaction velocity in rare cases.
E. The first and second choices are both correct.
111.
An update of Fischer's lock and key theory of enzyme specificity view the
_______ as the lock and _______ as the key.
A. * Enzyme; substrate
B. Substrate; enzyme
C. Enzyme; transition state
D. Transition state; enzyme
E. Substrate; transition state
112.
At 25 C. the optimum reaction rate of a certain enzyme occurs at a pH of 7. A
greater reaction rate could probably be attained by
A. * Increasing the temperature to 35 C and keeping the pH at 7
B. Increasing both the temperature and the pH
C. Decreasing the pH and increasing the temperature
D. Increasing the pH and keeping the temperature at 25 C.
E. All of the above
113.
At a blood test was set that activity of catalase is 5 units. It is a symptom of:
A. Hypoxia
B. Acidosis
C. * Anemia
D. Starvations
E. Diabetes mellitus
114.
At about 0 C., most enzymes are
A. * Inactive
B. Active
C. Destroyed
D. Replicated
E. Denaturated
115.
At hepatitis, heart attack in blood of patients activity of alanine- and aspartate
amino transferases sharply grow. What reasons of activation of these enzymes in blood?
A. An increase of intensity of disintegration of amino acid in tissues
B. Activation of amino acids synthesis in tissues
C. Activation of enzymes with hormones
D. * Damage of cells membranes and output of enzymes in blood
E. Lack of pyridoxine
116.
At high temperatures, the rate of enzyme action decreases because the increased
heat
A. Changes the pH of the system
B. * Alters the active site of the enzyme
C. Neutralizes the acids and bases in the system
D. Increases the concentration of the enzyme
117.
At parodontitis the secretion of kallikrein is increased. Choose, what strengtheners
of inflammatory reaction appear in an oral cavity as result the of this enzyme action?
A. Trasilol
B. * Kinins
C. Secretory immunoproteins
D. Lysozyme
E. Factor of nerves growth
118.
At the heart attack in blood of a patient were found out increase of enzymes
activity. Choose these enzymes:
A. * Creatin kinase, AsAT and LDH1,2
B. Mono amino oxidase
C. Cytochrome oxidase, AlAT
D. Carbo anhydrase
E. Lactate dehydrogenase
119.
Ca++ or Mg++ are most likely to be part of ___________, while Zn++ or Fe++
are present in _______________.
A. * Metal-activated enzymes; metalloenzymes
B. Metalloenzymes; metal-activated enzymes
C. Cofactors; coenzymes
D. Coenzymes; cofactors
E. Apoenzymes; holoenzymes
120.
Catalase is found in all cells and protects them from a dangerous waste chemical
by breaking it down into water and oxygen. What is this waste chemical?
A. * Hydrogen Peroxide
B. Nitrogen Dioxide
C. Lactic Acid
D. Carbon Monoxide
E. Urea
121.
Choose the enzyme which includes zinc?
A. * Alcohol dehydrogenase
B. Cytochromoxidase
C. Xantine oksidase
D. Pyruvate dehydrogenase
E. Lactate dehydrogenase
122.
Determination of amylase in blood can be diagnostic criteria for:
A. Nephritis
B. Glossitis
C. * Acute pancreatitis
D. Hepatitis
E. Anemia
123.
During a gastric secretion proteolytic enzymes are secreted as proenzymes. What
enzyme is activated with hydrochloric acid:
A. * Pepsinogen
B. Trypsinogen
C. Amylase
D. Lipase
E. Chymotrypsinogen
124.
Enzymes
A. Enhance reaction rate
B. Are affected by pH
C. Act on specific substrates
D. Are affected by temperature
E. * All of the above
125.
Enzymes catalyze transfer of structural fragments from one substrate to other with
formation of two products. Name the class of this enzyme.
A. * Transferase
B. Isomerase
C. Oxidoreductase
D. Ligase
E. Hydrolase
126.
Enzymes fast up the velocity of a biochemical reaction by
A. Increasing activation energy
B. Decreasing kinetic energy
C. Removing the functional group
D. * Decreasing activation energy
E. All of the above
127.
Enzymes influence chemical reactions in living systems by
A. Providing the substrate required for the reaction to occur
B. * Affecting the rate at which reactions occur
C. Absorbing water released when polymers are formed
D. Combining with excess hydrogen to form gaseous wastes
E. Increasing activation energy
128.
Enzymes of which class are responsible for transfer of structural fragment from
one substrate to other with formation of two products?
A. Oxidoreductases
B. Isomerases
C. * Transferases
D. Ligases
E. Hydrolases
129.
Enzymes that are activated by proteolytic cleavage are referred to as __________.
A. Covalently modified enzymes
B. Enzyme complexes
C. * Zymogens
D. Polymerized
E. Free radicals
130.
For a diet therapy at indigestion of milk for children used milk with diminish
maintenance of lactose with fermentative way. What enzyme is used for this aim?
A. * beta-galactosidase
B. beta-glycosidase
C. alpha- glycosidase
D. alpha-amilase
E. beta- amilase
131.
For diminishing of a patient’s depression used preparation, which inhibits
enzyme, catalyzing decomposition of biogenic amines. Name this enzyme:
A. * MAO (mono amino oxidase)
B. LDH (lactate dehydrogenase)
C. CPK (creatin phosphokinase )
D. ASAT (aspartate amino transferase)
E. ALAT (alanine amino transferase)
132.
For dissolving of scars, compressions, hematomas, the easier transport of
medications in tissues such enzyme is used:
A. Trypsin
B. Ribonuclease
C. * Hyaluronidase
D. Plasmin
E. Pepsin
133.
For prevention of intestine atony the competitive inhibitor of acetylcholine
esterase is recommended for a patient. Choose it:
A. * Prozerin
B. Aspirin
C. Zarin
D. Indometocin
E. Allopurinol
134.
For treatment of viral infections it is used such enzyme preparation:
A. Plasmin
B. Collagenase
C. Lizocym
D. Hyaluronidase
E. * DNA-ase, RNA-ase.
135.
From the human blood serum selected five isoenzyme forms which catalyze the
same reaction.Choose this enzyme:
A. Glutathione reductase
B. Ceruloplasmin
C. * Lactate dehydrogenase
D. Glucose-6-phosphate dehydrogenase
E. Superoxide dismutase
136.
Glucose + ATP > Glucose -6-phosphate + ADP. This reaction is catalysed by
which of the following enzyme classes
A. Oxidoreductase
B. * Transferase
C. Hydrolase
D. Lyase
E. Isomerases
137.
Glycoside hydrolases such as bacterial cellulase have been shown to differ in
mechanisms from that of lysozyme. They
A. Are alkaline catalysts
B. Form a boat form of the sugar
C. * Form a covalent sugar-enzyme intermediate
D. Do not distort the substrate
E. Have no active site side chain interactions
138.
How is nonprotein part of enzyme called?
A. Holoenzyme.
B. Apoenzyme.
C. * Cofactor.
D. Apoprotein.
E. None of the above
139.
How many active centers can have enzymes?
A. 1
B. 3
C. 2
D. * Depends on the amount of subunits of enzyme
E. 10
140.
How many classes of enzymes are there?
A. 4.
B. 5.
C. * 6.
D. 7.
E. 2
141.
In a multienzyme complex the process of directly transferring a product of one
reaction to the next active site without allowing it to enter the bulk solvent is termed
_______.
A. a ping-pong reaction
B. * metabolite channeling
C. the activity pathway
D. the sequential mode
E. All of the above
142.
In an organism was found the lack of copper. It will cause the decrease of such
enzyme activity:
A. Cytochrome b
B. Glucose oxidase
C. Catalase
D. * Cytochrome oxsidase
E. Glutation peroxidase
143.
In an organism was found the lack of iron. It will cause the decrease of such
enzyme activity:
A. Glutation peroxidase
B. Carboanhydrase
C. Carboxypeptidase
D. Ceruloplasmin
E. * Catalase
144.
In blood of patient found out the increase of activity of LDH 4,5, AlAT, carbamoil
ornitin transpherase. In which organ is it possible development of pathological process?
A. * In a liver (hepatitis is possible)
B. In a cardiac muscle (the heart attack of myocardium is possible)
C. In skeletal muscles
D. In kidneys
E. In connecting tissue
145.
In diagnostics of heart attack an important role belongs to the methods of
enzymodiagnostic. Determination of what enzyme level in blood of in the first 2-4 hours
after sharp pain is important for diagnostic?
A. * Creatin phosphokinase
B. Acetylcholine esterase
C. Lipoprotein lipase
D. Alanine amino transferase
E. Aldolase
146.
In enzyme controlled reactions, the role of certain vitamins such as niacin is to act
as
A. An enzyme
B. A substrate
C. * A coenzyme
D. A polypeptide
E. An allosteric centre
147.
In formation of temporal complex between an enzyme and substrate important
role belongs to chemical bonds, except:
A. Disulfide
B. Ion
C. * Peptid
D. Hydrogen bonds
E. Hydrophobic interaction
148.
In saliva there is an enzyme which has a strong bactericide action due to ability to
destroy 1-4 glycoside bonds of peptide-glycans of bacterial wall. Choose this enzyme:
A. Amylase
B. * Lizocim (muramidase)
C. Trypsin
D. Phosphatase
E. Ribonuclease
149.
In the human organism single-electron reduction of molecular oxygen superoxide,
hydroxyl radicals and hydrogen peroxide, which have high reactional ability appear
constantly. A hydrogen peroxide inactivated in an organism with:
A. Ceruloplasmin
B. * Catalase
C. Glutathione reductase
D. Glucose-6-phosphatedehydrogenase
E. Superoxide dismutase
150.
Induced fit studies by Koshland using the enzyme hexokinase showed that there
are enzyme forms
A. which react with the hydroxyl group of water
B. which react only with ATP and glucose present together
C. which are hydrophobic, excluding the competing hydroxyl group from water
D. * with and without glucose bound to each
E. that hydrolyze AT
151.
is known as _________ inhibition.
A. * Competitive
B. Uncompetitive
C. Uncompetitive
D. Feedback
E. Allosteric
152.
Isoenzymes are generally separated by
A. Ion exchange chromatography
B. Gel filtration chromatography
C. Paper chromatography
D. * Electrophoresis
E. Selective adsorbtion
153.
Izoenzymes differ between itself some physical and chemical properties, except:
A. Electrophoretic mobility
B. * Molecular activity
C. Stability
D. Present in different tissues
E. Different primary structure
154.
Km is _______.
A. The substrate concentration at ? Vmax.
B. = (k-1 + kcat)/k1
C. Related to an enzymes affinity for a specific substrate.
D. The Michaelis Constant
E. * All of the above
155.
Lactate + NAD+ ---> Pyruvate + NADH + H+
A. * Oxidoreductase
B. Transferase
C. Hydrolase
D. Lyase
E. Ligase
156.
Lactate dehydrogenase is a
A. Coenzyme
B. * Isoenzyme
C. Zymogen
D. Abzyme
E. Prostetic group
157.
Lipase, maltase, and protease are members of a group of compounds known as
A. Hormones
B. Carbohydrates
C. Lipids
D. * Enzymes
E. Coenzymes
158.
Lock and key theory was proposed by
A. Sumner
B. * Fischer
C. Sanger
D. Buchner
E. Michaelis
159.
Lyzocym is a antibacterial factor, muraminidase as a mechanism of action (splits
1-4 glycoside bonds of muramine). What class of enzymes does it belong to?
A. Transferases
B. Oxidoreductases
C. Lyases
D. Isomerases
E. * Hydrolases
160.
Mg2+ is used as a(n) _________ by metal activate enzymes that utilize negatively
charged substrates like ATP.
A. Metalloenzyme
B. * Activator ion
C. Prosthetic group
D. Co-substrate
E. Ingibitor ion
161.
NAD+, FAD, and FMN are all cofactors for:
A. * Oxidoreductases
B. Transferases
C. Hydrolases
D. Lyases
E. Ligases
162.
Name laboratory tests which should be conducted for the patients with suspicion
on a acute pancreatitis:
A. total blood test
B. Activity of LDH
C. Activity of AlAT
D. * Activity of amylase in urine and blood
E. A level of sugar in blood
163.
New antibiotics are synthesized with fermentative transformations of natural
antibiotics. What from the below named forms of enzymes are widely used in
pharmaceutical industry?
A. * Immobilized enzymes
B. Native enzymes
C. Denaturized enzymes
D. Complex of enzyme with a coenzyme
E. Complex of enzyme with an activator
164.
Noncompetitive inhibitor binds with
A. Active site
B. Allosteric site
C. Enzyme substrate complex
D. * Substrate
E. Product of reaction
165.
One of major enzymes of saliva, providing death of bacteria is:
A. * Lysozyme
B. LDH
C. Phosphatase
D. AsAT
E. AlAT
166.
Oxidases, peroxidases, oxygenases or reductases are all
A. Lyases
B. Synthases
C. Synthetases
D. * Oxidoreductases
E. Hydrolases
167.
Phenylketonuria of newborn may be diagnosed after a reaction of urine with:
A. * FeCI3
B. CuSO4
C. NaCl
D. Fe+
E. Na3PO4
168.
Prosthetic group of cytochrome is:
A. FAD
B. Ubiqinon
C. Biotin
D. * Iron porphyryn complex
E. Cooper contain porphyryn complex
169.
Pyridoxal phosphate is involved in which type of reaction?
A. oxidation of pyruvate
B. * production of new amino acids by transamination
C. phosphate-transfer to produce ATP from ADP
D. the regeneration of methionine from homocysteine
E. none of the above
170.
Pyruvate + H+ ---> Acetaldhyde + Carbon dioxide
A. Oxidoreductase
B. Transferase
C. Hydrolase
D. * Lyase
E. Ligase
171.
Pyruvate dehydrogenase complex is a multi-enzyme complex that catalyzes a
complicated multi-step reaction. The final reaction step is : FADH2 + NAD+ > FAD +
NADH + H+ The final step of this reaction falls into which enzyme class?
A. Transferases
B. Ligases
C. Lyases
D. * Oxidoreductases
E. Isomerases
172.
R-CH2OH + O2 > R-CHO + H2O2 which of the following types of enzymes
catalyzes this reaction
A. Dehydrogenae
B. Oxidase
C. * Peroxidase
D. Aldolase
E. Catalase
173.
Salivary amylase is an enzyme in humans that breaks down starch. The optimum
pH for this reaction is 6.7. The rate of this reaction would not be affected by
A. * Maintaining the pH of the reaction at 6.7
B. Substrate concentration
C. Enzyme concentration
D. Decreasing the temperature of the reaction by 5oC
E. Maintaining the pH of the reaction at 7.7
174.
Select the correct class of enzyme for this reaction. L-Glutamate + ATP + NH4+ --> L-glutamine + ADP + Pi
A. Oxidoreductase
B. Transferase
C. Hydrolase
D. Lyase
E. * Ligase
175.
Select the correct class of enzyme for this reaction. L-aspartic acid + ґketoglutarate ---> oxaloacetic acid + L-Glutamate
A. Oxidoreductase
B. * Transferase
C. Hydrolase
D. Lyase
E. Ligase
176.
Select the correct class of enzyme for this reaction. Sucrose + H2O ---> Fructose
+ Glucose
A. Oxidoreductase
B. Transferase
C. * Hydrolase
D. Lyase
E. Ligase
177.
Select the correct class of enzyme for this reaction. L-Glutamate + ATP + NH4+ --> L-Glutamine + ADP + Pi
A. Oxidoreductase
B. Transferase
C. Hydrolase
D. Lyase
E. * Ligase
178.
Select the correct class of enzyme for this reaction. Polypeptide + H2O --->
Amino acids
A.
B.
C.
D.
E.
Oxidoreductase
Transferase
* Hydrolase
Lyase
Ligase
179.
The analysis demonstrated a 10 times increase of diastase activity. The danger of
autolysis of a patient’s pancreas caused with activating of enzyme:
A. Amylase
B. Pepsin
C. * Trypsin
D. Lipase
E. Nuclease
180.
The biooxidation of xenobiotics takes place due to microsomal oxidation with
enzyme cytochrome P-450. What metal is the obligatory constituent of this enzyme?
A. * Fe
B. Zn
C. Na
D. Mg
E. K
181.
The class of enzymes that split peptide bonds or glycosidic bonds with water is
A. * hydrolases
B. lyases
C. transferases
D. isomerases
E. oxidoreductases
182.
The coenzyme biotin is involved in the transferring of the following groups
A. Amino group
B. * CO2
C. One carbon group
D. Acyl group
E. Amino acid residues
183.
The coenzyme present in transaminase
A. NAD+
B. TPP
C. Coenzyme A
D. * Pyridoxal phosphate
E. Biotin
184.
The defect of what enzyme results in disorders of decomposition of lactose at the
inherited genetic disorders of synthesis of enzymes in a human organism:
A. Amylase
B. Maltase
C. Sucrase
D. * Lactase
E. Peptidase
185.
The enzyme that catalyzes the reaction: glucose-6-phosphate + H2O > glucose +
phosphate can be assigned to which enzyme class?
A. oxidoreductases
B. isomerases
C. lyases
D. * hydrolases
E. transferases
186.
The enzyme which transfer groups between atoms within a molecule are
A.
B.
C.
D.
E.
Recemases
Mutases
* Transferases
Oxido-reductases
All of these
187.
The enzymes are inherent all physical and chemical properties of proteins, except:
A. High molecular mass
B. Breaking up to amino acid during a hydrolysis
C. Formation of colloid solutions
D. Antigen properties
E. * Stable to influence of high temperatures and salts of heavy metals
188.
The function of peroxidases is:
A. To split off hydrogen atoms or electrons from substrates and transfer them to any
acceptor except hydrogen peroxide and oxygen.
B. To split off hydrogen atoms or electrons from substrates and transfer them to
oxygen.
C. * To split off hydrogen atoms or electrons from substrates and transfer them to
hydrogen peroxide.
D. To decompose hydrogen peroxide.
E. To form hydrogen peroxide.
189.
The important enzyme of saliva is alkaline phosphatase. What class of enzymes
does it belong to?
A. * Hydrolases
B. Transferases
C. Oxidoreductases
D. Ligases
E. Lyases
190.
The inactive precursor of an active enzyme is called
A. * Zymogen
B. Ribozyme
C. Isozyme
D. Abzyme
E. Nucleozyme
191.
The inhibition of succinate dehydrogenase by malonate is an example for
A. * Competitive inhibition
B. Non competitive inhibition
C. Uncompetitive inhibition
D. Feedback or end product inhibition
E. None of these
192.
The inhibitors of proteolytic enzymes were recommended for a patient. For what
purpose necessary to apply such preparations:
A. * To avoid autolysis of pancreas.
B. To promote autolysis of pancreas.
C. To promote a hepatotoxity.
D. To reduce a hepatotoxity.
E. All answers are correct
193.
The ions of what metal contain porphirine coenzymes?
A. Na
B. * Fe
C. Zn
D. Mo
E. Mn
194.
The laboratory test allows diagnosing infarction of myocardium. The increase of
what enzyme in blood proves it?
A. LDH4,5
B. Arginase
C. Pyruvate dehydrogenase
D. * AsAT
E. ALAT
195.
The list of cofactors which are able in the process of fermentative reactions to
carry electrons and protons is below resulted, except of one cofactor which carries
chemical groups only. Choose it:
A. NAD
B. * Pyridoxal phosphate
C. FAD
D. Ubiqinon (coenzyme Q)
E. Hem coenzymes
196.
The mechanism of action of lysozyme include
A. Distortion of the substrate
B. Acid catalysis
C. Proximity effects
D. Formation of a half-chair sugar form
E. * All of the above
197.
The optimal pH for the enzyme pepsin is
A. * 1.0–2.0
B. 4.0–5.0
C. 5.2–?6.0
D. 5.8–6.2
198.
The patient with cyanide poisoning was delivered to clinic. What mast be
immediately used for the improvement of his state?
A. Glucose
B. Ascorbic acid
C. * Cytochromoxidase
D. Vitamin B1
E. Nicotine amide
199.
The protective function of saliva is predefined a few mechanisms, including
presence of enzyme, which has a bactericidal action, causes the lysis of polysaccharide
complex of membranes of staphylococcuss, streptococci. Name this enzyme.
A. Beta-glyucuronidase
B. Alfa-amylase
C. Oligo-1,6-glucosidase
D. Collagenase
E. * Lysozyme
200.
The term ligase refers to a class of enzymes that catalyzes_________.
A. Oxidation reduction reactions
B. Reactions involving the transfer of a functional group from one molecule to
another
C. Hydrolytic cleavages
D. * Reactions where two molecules are joined together
E. All of the above
201.
The uncompetitive inhibitor binds with
A. Active site
B. Allosteric site
C. * Enzyme substrate complex
D. Substrate
E. Product of reaction
202.
TPP is a/an _____________ of yeast pyruvate decarboxylase.
A. Cosubstrate
B. Intrinsic factor
C. Metalloenzyme
D. Prosthetic group
E. * Coenzyme
203.
Vitamins are essential to the survival of organisms because vitamins usually
function as
A. Substrates
B. Nucleic acids
C. * Coenzymes
D. Nucleotides
E. Enzymes
204.
What component is not included in the structure of holoenzymes?
A. Apoenzyme
B. Coenzyme
C. Cofactor
D. Prostetic group
E. * Izoenzyme
205.
What enzymes are located in the ribosomes?
A. * Ligases.
B. Oxido-reductases.
C. Transferases.
D. Isomerases.
E. Hydrolases.
206.
What enzymes catalyses the hydrolysis of triglycerides in the smal intestine?
A. * Lipases
B. Acetyl cholinesterases
C. Phospholipases
D. Transacylases
E. Monoglycerol lipases
207.
What is the area of an enzyme called where the chemical reactions occur?
A. The Cytoplasm
B. * The Active Site
C. The Catalyst
D. The Nucleus
E. A substrate
208.
What is the cause of primary enzymo-pathologies?
A. Liver diseases.
B. * Genetic disorders.
C. Trauma.
D. Ischemia.
E. All of these
209.
What is the chemical nature of enzymes?
A. Carbohydrates.
B. Lipids.
C. * Proteins.
D. Nucleic acids.
E. Fatty acids
210.
What kind of reaction do hydrolases catalyze?
A. * This group of enzymes catalyses hydrolytic cleavage reactions (such as the
formation of glucose from maltose by the action of the enzyme maltase).
B. These enzymes are involved in electron transfer oxidation/reduction reactions,
such as those in photosynthesis and cellular respiration.
C. These enzymes are involved in functional groups transfer
D. This group of enzymes catalyses none-hydrolytic cleavage reactions.
E. None of the above
211.
What kind of reactions is catalized by hydrolases?
A. * Hydrolytic cleavage of substrates.
B. Oxidation-reduction reactions.
C. Addition to double bonds.
D. Formation of bonds with ATP cleavage.
E. Synthesis of compounds
212.
What of the following statements are not true for the isoenzymes?
A. They differ in amino acid composition.
B. * They catalyze different reactions.
C. They differ in physical properties.
D. They are coded by different genes.
E. They active in different organs
213.
What pathology is developed in the absence of phenylalanine 4-monooxygenase?
A. * Phenylketonuria.
B. Alkaptonuria
C. Galactosemia.
D. Hyperglycemia.
E. Achilia
214.
What reactions would oxidoreductases is involved in?
A. This group of enzymes catalyses hydrolytic cleavage reactions (such as the
formation of glucose from maltose by the action of the enzyme maltase).
B. * These enzymes are involved in electron transfer oxidation/reduction reactions,
such as those in photosynthesis and cellular respiration.
C. These enzymes are involved in functional groups transfer
D. This group of enzymes catalyses none-hydrolytic cleavage reactions.
E. None of the above
215.
What structure of proteins molecule is responsible for formation of active centre
and for it catalytic action?
A. Primary
B. * Tertiary
C. Secondary
D. Quaternary
E. None from above
216.
Where are the hydrolases located in the cell?
A. In mitochondria
B. In nucleus.
C. In cytoplasm
D. * In lysosoms
E. In complex Golgi
217.
Which chemical is classified as an enzyme?
A. Galactose
B. Lipid
C. * Protease
D. Manganese dioxide
E. Sucrose
218.
Which cofactor has the following properties: a) forms Schiff base, b) its precursor
is absorb dietarily as Vitamin B6, c) is required in a number of reactions in aminoacid
metabolism.
A. Thiamin pyrophosphate
B. Biotin
C. Lipoamide
D. * Pyridoxal phosphate
E. Nicotinamid
219.
Which factor does not alter the rate of hydrolysis of maltose?
A. Temperature of the environment of the reaction
B. A pH of the environment of the reaction
C. Number of enzyme molecules present
D. * Size of the substrate molecule
E. None of the above
220.
Which group of organic compounds includes the enzymes?
A. * Proteins
B. Starches
C. Carbohydrates
D. Lipids
E. Nucleic acids
221.
Which of the following coenzymes functions in acyl transfer reactions?
A. NADPH
B. * Coenzyme A
C. Biotin
D. A and b
E. B and c
222.
Which of the following enzymes would digest a fat?
A. Sucrase
B. Fatase
C. Protease
D. * Lipase
E. None of the above
223.
Which property is common for enzymes and inorganic catalysts?
A. Specificity
B. Sensitiveness to the action of external factors
C. * Catalysis only thermodynamically possible reactions
D. Dependence from рН and temperature
E. High catalytic activity
224.
Which statement describes the currently accepted theory of how an enzyme and
its substrate fit together?
A. As the product is released, the enzyme breaks down.
B. The enzyme is like a key that fits into the substrate, which is like a lock.
C. The active site is permanently changed by its interaction with the substrate.
D. * As the substrate binds to the enzyme, the shape of the enzyme site changes to
accommodate the reaction.
E. All of the above
225.
Which statement is false about allosteric regulation?
A. * It is usually the mode of regulation for the last step in reaction pathways since
this step produces the final product.
B. Cellular response is faster with allosteric control than by controlling enzyme
concentration in the cell.
C. The regulation usually is important to the conservation of energy and materials in
cells.
D. Allosteric modulators bind non-covalently at sites other than the active site and
induce conformational changes in the enzyme.
E. B and C
226.
Which statement is false about regulatory enzymes that are controlled
allosterically?
A. * They are always less active when a modulator is bound to them.
B. They are often larger than other enzymes.
C. They have more than one binding site.
D. They often catalyze the first step in a reaction pathway.
E. They have more than two binding site.
227.
Which statement regarding enzyme function is true?
A. Higher temperatures allow greater contact between enzymes and substrates;
therefore, the higher the temperature the better the enzyme will function.
B. Enzymes cannot function at a pH lower than 6.
C. Most coenzymes are inorganic substances such as ions of iron or potassium.
D. Excessive salt ions can cause an enzyme to denature.
E. * All of the above.
228.
Which type of specificity of enzymes does not exist?
A. Relative
B. Absolute
C. * Conformation
D. None of above
E. Stereospecificity
229.
Which vitamins does not appear as coenzymes?
A. B1
B. B2
C. B5
D. * С
E. B12
230.
Wich enzymes do not include porphyrine coenzymes?
A. Cytochrome b, с
B. Catalase
C. Peroxidase
D. * Phosphatase
E. Cytochrome а1, а
231.
With ageing in cartilaginous decreases intensity of proteoglycans formation that
leads to diminishing of degree of their hydratation and loss of tissues turgor. Activity of
what enzymes of lysosomes does increase?
A. Deaminase, decarboxylase
B. Isomerase, dehydrogenases
C. Protease, lipase
D. Oxidoreductases, phosphstase
E. * Cathepsins, glycosidase
232.
With urine of newborn was done a reaction with FeCI3 and a positive reaction
(dark color) got. What disease is possible?
A. Galactosemia
B. Tirosinosis
C. * Phenylketonuria
D. Alkaptonuria
E. Aminoaciduria.
233.
Zinc is present in which of the following enzymes
A. Cytochrome oxidase
B. Arginase
C. Hexokinase
D. * Alcoholdehydrogenase
E. Catalase
234.
Zymogens are inactive enzyme precursors which are made active by
A. A change in structure
B. Selective proteolysis
C. Secretion to new types of cells
D. a and b
E. * a, b and c
235.
An amphibolic pathway among the following is
A. HMP shunt
B. Glycolysis
C. * Citirc acid cycle
D. Gluconeogenesis
E. A and B
236.
ATP is an energy-rich molecule because:
A. it contains adenine;
B. it contains monosaccharide ribose that can be oxidized with energy formation
C. * its triphosphate unit contains two phosphoanhydride bonds
D. it forms complex with Mg2+ or Mn2+
E. all of the above
237.
Isocitrate dehydrogenase can use __________ as a cofactor.
A. NAD+ only
B. NADP+ only
C. * NAD+ or NADP+
D. FMN and FAD
E. TPP only
238.
Isocitrate dehydrogenases is
A. * Aerobic dehydrogenase
B. Anaerobic dehydrogenase
C. Hydroperoxidase
D. Oxygenase
E. Ligase
239.
Name the common product of the second stage of catabolism of carbonhydratess,
lipids and amino acids.
A. * Acetyl-CoA.
B. Pyruvate
C. Citric acid.
D. Acyl-CoA.
E. ATP
240.
Pyruvate dehydrogenase complex and ?-ketoglutarate dehydrogenase complex
require the following for their oxidative decarboxylation:
A. COASH and Lipoic acid
B. NAD+ and FAD
C. COASH and TPP
D. * COASH, TPP,NAD+,FAD, Lipoate
E. A and C
241.
Pyruvate dehydrogenase is a/an
A. Isomerase
B.
C.
D.
E.
Lyase
Ligase
* Oxido reductase
Transferase
242.
The number of molecules of ATP produced by the total oxidation of acetyl CoA
in TCA cycle is
A. 6
B. 8
C. 10
D. * 12
E. 15
243.
Which of the following is located in the mitochondria?
A. Cytochrome oxidase
B. Succinate dehydrogenase
C. Dihydrolipoyl dehydrogenase
D. * All of these
E. None of these
244.
Which of the following metabolite integrates glucose and fatty acid metabolism?
A. * Acetyl CoA
B. Pyruvate
C. Citrate
D. Lactate
E. None of the above
245.
_____ is another term for biosynthesis.
A. Catabolism
B. * Anabolism
C. . Metabolism
D. Catalyst
E. Oxidation
246.
A deficiency in thiamin causes the disease beriberi. Which might you expect to
have a higher than normal blood concentration in an individual with this condition?
A. isocitrate
B. * pyruvate
C. oxaloacetate
D. acetyl CoA
E. malate
247.
A patient was diagnosed with beri-beri disease. Activity of which enzyme is
inhibited in an organism of the patient?
A. Fumarase
B. Citrate synthase
C. Malate dehydrogenase
D. Succinate dehydrogenase
E. * Pyruvate dehydrogenase
248.
Among citric acid cycle enzymes, a flavoprotein is
A. Malate
B. Fumarase
C. * Succinate dehydrogenase
D. Isocitrate dehydrogenase
E. All of these
249.
Among the many molecules of high-energy phosphate compounds formed as a
result of the functioning of the citric acid cycle, one molecule is synthesized at the
substrate level. In which of the following reactions does this occur?
A.
B.
C.
D.
E.
Citrate C-ketoglutarate
* B-ketoglutarate --succinate
Succinate SSfumarate
Fumarate FFmalate
Malate MMoxaloacetate
250.
Anabolic pathways _______
A. Do not depend on enzymes.
B. * Consume energy to build up polymers from monomers.
C. Lead to the synthesis of catabolic compounds.
D. Release energy as they degrade polymers to monomers.
E. All of the above
251.
Anabolic reactions with the formation of new bonds and utilization of ATP energy
are catalyzed by:
A. oxidoreductases;
B. hydrolases;
C. isomerases;
D. * ligases.
E. transferases
252.
As resalt of hypovitaminosis a 55 years old man has sympthoms of oxidative
decarboxilation of pyruvate inhibition. Oxidative decarboxilation of pyruvate results in
formation of molecules ATP:
A. 2 ATP
B. * 3 ATP
C. 15 ATP
D. 12 ATP
E. 38 ATP
253.
As resalt of hypovitaminosis a 55 years old woman has sympthoms of oxidative
decarboxilation of pyruvate inhibition. Aerobic oxidation of pyruvate to CO2 and H2O
results in formation of molecules ATP:
A. 38 ATP
B. 12 ATP
C. 3 ATP
D. * 15 ATP
E. 2 ATP
254.
As resalt of hypovitaminosis and low activity of enzymes a man has sympthoms
of oxidative decarboxilation of pyruvate inhibition. Cofactors of dehydrogenases are all,
except one:
A. NAD+
B. * c-AMP
C. NADP+
D. FMN
E. FAD
255.
Before pyruvic acid enters the TCA cycle it must be converted to
A. * Acetyl CoA
B. Lactate
C. Alfa-ketoglutarate
D. Citrate
E. Malate
256.
Before pyruvic acid enters the TCA cycle it must be converted to
A. * Acetyl CoA
B. Lactate
C. Alfa-ketoglutarate
D. Citrate
E. Malate
257.
Compounds like succinate, fumarate and а-ketoglutarate have a catalytic effect on
the consumption of oxygen in a cell suspension. The rate of oxygen consumption is far
more than that required for their own oxidation. This is evidence that ________.
A. they are intermediates in glycolysis
B. they act as enzymes to cause the oxidation of other compounds
C. * they are involved in a cyclic pathway
D. they must be cofactors for enzymes that are oxidoreductases
E. All of these
258.
Dehydrogenation of succinic acid to fumaric acid requires the following hydrogen
carrier:
A. NAD+
B. NADP+
C. * flavoprotein
D. Glutathione
E. FAD
259.
Dehydrogenation of succinic acid to fumaric acid requires the following hydrogen
carrier:
A. NAD+
B. NADP+
C. * Flavoprotein
D. Glutathione
E. Both A and C
260.
During wet beriberi, peripheral vessels dilate and heart muscles loose their
contractility. Some people think this is a result of a failure of the TCA cycle. Evidence
for this is an increase in the
A. Rate of production of succinate
B. Rate of production of NADH
C. * Concentration of alpha-ketoglutarate and pyruvate
D. Production of ATP
E. Production of FADH2
261.
During wet beriberi, peripheral vessels dilate and heart muscles loose their
contractility. Some people think this is a result of a failure of the TCA cycle. Evidence
for this is an increase in the
A. Rate of production of succinate
B. Rate of production of NADH
C. * Concentration of alpha-ketoglutarate and pyruvate
D. Production of ATP
E. Production of FADH2
262.
For the two years old boy of a energy metabolism is inhibited due to processes of
oxidation and ATP formation. Maintenance of metabolites of Krebs cycle in blood is
decreased. What product of metabolism is the competitive inhibitor of Succinate
dehydrogenase?
A. * Malonate
B. Malate
C. Aspartate
D. Glutamate
E. Citrate
263.
For treatment of many diseases cocarboxylase (thiaminpyrophosphate) is used for
providing of energy for cells. Choose what metabolic process is activated in this case?
A. * oxidative decarboxilation of pyruvate
B.
C.
D.
E.
deamination of glutamate
decarboxilation of histidin
transamination of aspartate
substrate level phosphorylation
264.
How many ATP molecules can be derived from each molecule of acetyl CoA that
enters the Krebs’ Cycle?
A. 6
B. * 12
C. 18
D. 38
E. 39
265.
How many molecules of ATP are formed during the full oxidation of 1 molecule
of acetyl CoA?
A. * 12.
B. 24.
C. 36.
D. 38.
E. 15.
266.
How many molecules of NADH is formed during the conversion of ONE
molecule of pyruvate to acetyl CoA?
A. * 1;
B. 2;
C. 3;
D. NADH2 is not formed, 1 molecule of NADPH is produced.
E. 4
267.
How many substrate level phosphorylation reactions are in tricarboxylic acid
cycle?
A. * 1;
B. 2;
C. 3;
D. 5;
E. there are not substrate level phosphorylation reactions.
268.
Hyperproduction of insulin by pancreas of 35 years old patient caused activation
of TCA. The citric acid cycle oxidizes pyruvate and some of the pathway intermediates
are starting materials for many biosynthetic pathways. This means the citric acid cycle is
a/an ______________.
A. amplifying pathway
B. strictly catabolic pathway
C. anaerobic pathway
D. * amphibolic pathway
E. both A and D
269.
In blood and urine of a patient is increased value of pyruvic and ?-ketoglutaric
acids. The deficiency of which coenzyme causes these changes?
A. Pyridoxal phosphate
B. * Thiamin pyrophosphate
C. Flavin mononucleotide
D. Biotin
E. Ubiqinon
270.
In blood and urine of a patient it was takes place increase value of pyruvic and
ketoglutaric acids. The deficiency of which coenzyme causes these changes?
A. Pyridoxal phosphate
B. * Thiamin pyrophosphate
C. Flavin mononucleotide
D. Biotin
E. Ubiqinon
271.
In citric acid cycle, GDP is phosphorylated by
A. Succinate dehydrogenase
B. Aconitase
C. * Succinate thiokinase
D. Fumarse
E. Alfa-ketoglutarate dehydrogenase
272.
Luck of insulin caused inhibition of TCA in the organism of 35 years old patient.
For one turn of Krebs cycle ATP molecules are formed:
A. 38 ATP
B. * 12 ATP
C. 15 ATP
D. 1 ATP
E. 15 ATP
273.
Metabolism is defined as:
A. a sequence of reactions that has a specific purpose;
B. * the entire network of chemical reactions carried out by living cells;
C. degradation of macromolecules molecules to create smaller molecules and
energy;
D. synthesis of the molecules for cell maintenance, growth and reproduction.
E. none of the above
274.
Most CO2 produced during aerobic cellular respiration is released during
A. Oxidative phosphorylation
B. Lactate fermentation.
C. * The Kreb’s cycle
D. Electron transport
E. Glycolysis.
275.
NAD and NADP dependent dehydrogenases catalyze substrates by transferring
__________ to C-4 of NAD+ and NADP+.
A. An electron
B. Two electrons
C. An electron and a proton
D. * Two electrons and a proton
E. Two electrons and two protons
276.
NADH ____________ Krebs cycle and ATP _______________ it.
A. activates; activates;
B. activates; inhibits;
C. inhibits; activates;
D. * inhibits; inhibits;
E. none of the above.
277.
One of the affects of thiamin deficiency in alcoholics is that muscles do not
contract adequately. An explanation for this is that:
A. * Alpha-ketoglutarate in the TCA cycle requires thiamin
B. Glucose-6-phosphate dehydrogenase has an absolute requirement for thiamin
C. Pyruvate carboxylase has a requirement for thiamin
D. Thiamin is an intermediate in the electron transport chain
E. Myosin ATPase has an absolute requirement for thiamin
278.
Organism suffers from hypovitaminosis of B5. How will it change the function of
oxidoreductases?
A. It will inhibit synthesis and functions of cytochroms
B. It will inhibit synthesis and functions of FMN and FAD – dependent
dehydrogenases
C. It causes improper synthesis and functions of TPP, which is the coenzyme of
pyruvate dehydrogenase.
D. It causes inhibition of synthesis and functions of aminotransferases.
E. * It causes inhibition of synthesis and functions of NAD and NADP – dependent
oxidoreductases (dehydrogenases)
279.
Out of 24 mols of ATP formed in TCA cycle, 2 molecules of ATP can be formed
at “substrate level” by which of the following reaction ?
A. Citric acid>?Isocitric acid
B. Isocitrate>?Oxaloacetate
C. Succinic acid>?Fumarate
D. * Succinyl CoA>?Succinic acid
E. A and B
280.
Patient suffers from severe hypovitaminosis, low activity of dehydrogenases.
Cofactors of dehydrogenases are all, except one:
A. NAD+
B. * c-AMP
C. NADP+
D. FMN
E. FAD
281.
Patient with hypofunction of thyrod gland suffers from loose ob body weight as
result of catabolism activation. Catabolism is characterized by _______________ of three
major routs toward a final common pathway.
A. divergence;
B. * convergence;
C. splitting;
D. none of the above.
E. all of the above.
282.
Patient with hypofunction of thyrod gland suffers from general weakness due to
inhibition of metabolism. Metabolism is defined as:
A. a sequence of reactions that has a specific purpose;
B. * the entire network of chemical reactions carried out by living cells;
C. degradation of macromolecules molecules to create smaller molecules and
energy;
D. synthesis of the molecules for cell maintenance, growth and reproduction.
E. none of the above
283.
Pyruvate passes through the outer mitochondrial membrane by _____________.
A. * porin proteins
B. passive transport
C. pyruvate translocase
D. simple diffusion through the lipid bilayer
284.
Pyruvate translocase is a/an _________________ protein that transports
____________.
A. antiport; pyruvate and H+ in opposite directions
B. uniport; only pyruvate
C. * symport; pyruvate and H+ in the same direction
D. antiport; pyruvate and CO2 in opposite directions
E. symport; pyruvate and CO2 in the same direction
285.
Rate of the TCA reactions in an organism of 55 years old patient with diabetes
mellitus is decreased. The oxidation of acetyl CoA in citric acid cycle to CO2 and water
is the _________ stage of catabolism and this is ___________ stage.
A.
B.
C.
D.
E.
first, specific;
second, nonspecific;
third, specific;
* third, nonspecific.
second, specific.
286.
Reduction of which one of the following substrates leads to a reducing equivalent
in a step of the citric acid cycle?
A. Succinyl CoA
B. * Malate
C. Fumarate
D. Oxaloacetate
E. Citrate
287.
Substrate level phosphorylation in TCA cycle is in step:
A. Isocitrate dehydrogenase
B. Malate dehydrogenase
C. Aconitase
D. * Succinate thiokinase
E. None of these
288.
Substrate level phosphorylation in TCA cycle is in step:
A. Isocitrate dehydrogenase
B. Malate dehydrogenase
C. Aconitase
D. * Succinate thiokinase
E. Alfa-ketoglutarate dehydrogenase
289.
The accumulation of pyruvate in blood, decrease of activity of transketolase of red
blood cells takes place in organism of a 46 years old chronic alcoholic. Insufficiency of
coenzyme form of which vitamin causes such changes?
A. * Thiamine diphosphate
B. Carboxybiotin
C. Metylcobalamin
D. Phosphopyridoxal
E. Tetrahydrofolate
290.
The coenzyme electron carriers produced in the Krebs cycle are
A. ATP and ADP
B. Pyruvate and acetyl CoA
C. * FADH2 and NADH
D. NAD and NADH
E. NADH and ATP
291.
The coenzyme not involved in the formation of acetyl-CoA from pyruvate is
A. TPP
B. * Biotin
C. NAD
D. FAD
E. Both A and B
292.
The conversion of pyruvate to acetyl CoA and CO2
A. Is reversible
B. * Involves the participation of lipoic acid
C. Depends on the coenzyme biotin
D. Occurs in the cytosol
E. All of the above
293.
The conversion of pyruvate to acetyl CoA and CO2
A. Is reversible
B.
C.
D.
E.
* Involves the participation of lipoic acid
Depends on the coenzyme biotin
Occurs in the cytosol
Both A and B
294.
The high toxicness of ammonia for the neurons of CNS is predetermined braking
of TCA and, as a result, decline of the tissue respiration, oxidative phosphorylation ,
ketonemia. Reason is a binding of ammonia to the following components of cycle:
A. * A - ketoglutarate
B. Isocitrate
C. Succinate
D. Fumarate
E. Oxaloacetate
295.
The number of ATP produced in the succinate dehydrogenase step is
A. 1
B. * 2
C. 3
D. 4
E. 5
296.
The number of ATP produced in the succinate dehydrogenase step is
A. 1
B. * 2
C. 3
D. 4
E. 5
297.
?The patient with cyanide poisoning was delivered to clinic. What mast be
immediately used for the improvement of his state?
A. Glucose
B. Ascorbic acid
C. * Cytochromoxidase
D. Vitamin B1
E. Nicotine amide
298.
The rate at which pyruvate from glycolysis is used by the TCA cycle to produce
energy is regulated by pyruvate dehydrogenase. During muscle contraction, this enzyme
is
A. Inhibited by increases in the calcium concentration.
B. Activated by increased in acetyl CoA
C. Activated by increases in NADH
D. * Activated by increases in ADP
E. Inhibited by increases in AMP
299.
Your patient is an alcoholic a buildup of a-ketoacids and symptoms of wet
beriberi. All of the following might be part of a scenario that would explain why
peripheral vessels dilate and cardiac muscles loose their contractility EXCEPT
A. Muscle needs ATP to contract
B. Most ATP is produced by oxidative phosphorylation
C. NADH and FADH2 are produced by the TCA cycle
D. The TCA cycle needs thiamine pyrophosphate to function
E. * A shortage of thiamine results in the inability to oxidize NADH
300.
_____ is another term for biosynthesis.
A. Catabolism
B. Anabolism
C. * Metabolism
D. Catalyst
E. Oxidation
301.
2,4-Dinitrophenol and oligomycin inhibit mitochondrial oxidative
phosphorylation. 2,4-Dinitrophenol is an uncoupling agent; oligomycin blocks the ATP
synthesis reaction itself. Therefore, 2,4-dinitrophenol will:
A. * Allow electron transfer in the presence of oligomycin.
B. Allow oxidative phosphorylation in the presence of oligomycin.
C. Block electron transfer in the presence of oligomycin.
D. Diminish O2 consumption in the presence of oligomycin
E. Do none of the above.
302.
A chemical reaction that has a positive DeltaG is correctly described as _______
A. Exothermic.
B. Exergonic.
C. * Endergonic.
D. Enthalpic.
E. Spontaneous.
303.
A chemical reaction with a positive Go' would be considered a/an
A. Exergonic reaction.
B. Energy generating reaction.
C. Catabolic reaction.
D. * Endergonic reaction
E. A and B
304.
A compound with a greater free energy of hydrolysis than ATP is
A. Glucose 1-phosphate
B. Any phosphoester
C. * Phosphoenolpyruvate
D. Acetyl CoA
E. All of the above
305.
A distinct set of metabolic reactions is called a reaction ________________.
A. Network
B. Cycle
C. * Pathway
D. Mechanism
E. A and B
306.
A molecule who’s function is to release energy quickly is a
A. Fatty acids
B. Nucleic acids
C. * Monosaccharides
D. Amino acids
E. Vitamins
307.
A process common to all living organisms, aerobic and anaerobic, is
A. * Glycolysis
B. Fermentation
C. The Krebs cycle
D. Electron transport chain reactions
E. Pyruvate oxidation
308.
A reduced compound is
A. NAD
B. FAD
C. * NADH
D. ADP
E. ATP
309.
A third class of inhibitors - hydrogen cyanide, hydrogen sulfide, and carbon
monoxide block electron transport from:
A. Cytochrom c to CO2
B. * Cytochrome aa3 to oxygen
C. Cytochrom b to c
D. Cytochrom b to aa3
E. NADH to Fe-S proteins
310.
After adding of 1-2 drops of NADI-reagent on the boiled portion of muscles the
color doesn't appear - is the result of the:
A. Soulting-out of proteins
B. * Enzyme denaturation
C. Enzyme renaturation
D. Enzyme decarboxilation
E. Activation of enzymes
311.
All of the following processes produce ATP, except:
A. * Lactic acid formation
B. Oxidative phosphorilation
C. Glycolysis
D. The Krebs cycle
E. The electron transport chain
312.
All of the following statements about NAD+ are false except:
A. NAD+ has the appearance of a double nucleotide
B. * NAD+ is reduced to NADH by way of acceptance of a single electron and
proton
C. NAD+ catalyzes the reactions of glycolysis by acting as an enzyme
D. NAD+ provides the energy necessary for the non-spontaneous reactions of
glycolysis to occur
E. NAD+ has more chemical energy than does NADH
313.
Almost all of the oxygen (O2) one consumes in breathing is converted to:
A. Acetyl-CoA.
B. Carbon dioxide (CO2)
C. Carbon monoxide and then to carbon dioxide.
D. None of the above.
E. * Water.
314.
An electron transferred in a biological system is usually
A. Boosted to a higher light energy state
B. * Converted into other chemical compounds
C. Accompanied by a proton
D. Given off as radiant energy
E. Lost to the system as heat
315.
As energy is being reconverted through the many forms, it is continuously lost as
A. Electricity
B. Light
C. Sound
D. Heat
E. * Chemical energy
316.
At one time the uncoupler 2,4-dinitrophenol was used as a weight reducing drug.
Its side-effects, including death, resulted in its discontinued use. How could this drug
cause weight loss?
A. * The uncoupler allows the oxidation of fats from adipose tissue without the
production of ATP. This allows the oxidation to proceed continuously and uses up
the fats.
B. The uncoupler causes ATP to be produced at a much higher rate than normal and
this causes weight loss.
C. The uncoupler inhibits the transport of pyruvate into the matrix of the
mitochondria. Fats are then degraded to glycerol to subsequently to pyruvate to
provide the necessary energy. Thereby depleting fat stores.
D. The uncoupler is an allosteric activator of ATP synthase. This increases the rate
of translocation of H+ and the oxidation of fuels, including fats.
E. B and C only
317.
ATP can be used to activate a substrate by
A. Phosphorylation
B. Adding a nucleotidyl group
C. Producing inorganic phosphate
D. * Both a and b
E. A, b, and c
318.
ATP is the most commonly used source of energy rich compounds in cells
because
A. It complexes with Mg++
B. It has a higher free energy of hydrolysis
C. Its products of hydrolysis are more stable the ATP
D. * It is used more often than other nucleoside triphoshates
E. It engages in phosphoryl-group transfers
319.
ATP is thermodynamically suited as a carrier of phosphoryl groups in animal cells
because
A. It is stable under cell conditions
B. It is not hydrolyzed in cells without enzyme action
C. It is intermediate in group-transfer potential
D. It can be produced from phosphocreatine
E. * All of the above
320.
ATP synthase complexes can generate _______ATP(s) for each NADH that
enters electron transport.
A. * 1
B. 2
C. 3
D. 4
E. 8
321.
Carrier molecules in the cell membrane and metabolic energy are required for:
A. Osmosis
B. Facilitated diffusion
C. * Active transport
D. All the above
E. B & C only
322.
Cells store energy when _____.
A. * The third phosphate group breaks off from an ATP molecule
B. They break down sucrose to glucose and fructose
C. A third phosphate group is bonded to an ATP molecule
D. Ions are released into the bloodstream
E. None of the above
323.
Chemiosmotic generation of ATP is driven by
A. Phosphate transfer through the plasma membrane
B. Sodium, potassium pump
C. * A difference in H+ concentration on the two sides of the mitochondrial
membrane
D. Osmosis of macromolecules
E. Large quantities of ADP
324.
Consider the synthesis of a biopolymer in which the addition of successive
monomers occurs by the same kind of reaction(s). The synthesis of the polymer is a
________ pathway.
A. Linear
B. Cyclic
C. * Spiral
D. Branched
E. A and B
325.
Cytochrome P450 is a two-enzyme sequence in eucaryotes, containing both FAD
and FMN. The function of these coenzymes is
A. Reduce O2
B. React with foreign or natural substance indicated by RH
C. * Carry electrons from NADPH to oxygen
D. Provide a hydrophobic channel in the protein pocket
E. All of the above
326.
During oxidative phosphorylation, the proton motive force that is generated by
electron transport is used to:
A. Create a pore in the inner mitochondrial membrane
B. Generate the substrates (ADP and Pi) for the ATP synthase
C. * Induce a conformational change in the ATP synthase
D. Oxidize NADH to NAD+
E. Reduce O2 to H2O
327.
Each NAD molecule carryng hydrogen to the electron transport chain can produce
how mane moleculs of ATP?
A. 1
B. 2
C. * 3
D. 4
E. Cannot be determine
328.
Energy from sunlight is trapped by chlorophyll located in the _____.
A. Citric acid cycle
B. * Mitochondria
C. Electron transport chain
D. Thylakoid membranes
E. Synthesis of urea
329.
Energy is carried from catabolic to anabolic reactions in the form of
A. ADP
B. * High-energy ATP bonds
C. Coenzymes
D. Inorganic phosphate
E. Oxygen
330.
Energy is released from ATP when the bond is broken between _____.
A. * Two phosphate groups
B. Adenine and ribose
C. Ribose and a phosphate group
D. Adenine and a phosphate group
E. B and C only
331.
Energy requiring metabolic pathways that yield complex molecules from simpler
precursors are:
A. Amphibolic
B.
C.
D.
E.
* Anabolic
Autotrophic
Catabolic
Heterotrophic
332.
enough free energy to rephosphorylate:
A. 6 ATP
B. * 5 ATP
C. 4 ATP
D. 3 ATP
E. None of the above are correct
333.
Enzymes are biological catalysts that enhance the rate of a reaction by:
A. * Decreasing the activation energy
B. Decreasing the amount of free energy released
C. Increasing the activation energy
D. Increasing the amount of free energy released
E. Increasing the energy of the transition state
334.
Exergonic reactions
A. * Release potential energy
B. Consume energy
C. Form bonds
D. Occur only outside the cell
E. All of the above
335.
Fermentation can be described as a process
A. * That takes place only in the absence of oxygen
B. In which the recipient of hydrogen atoms is an organic molecule
C. In which water is not one of the by-products
D. In which the Krebs cycle and electron transfer through ETS do not occur
E. All of the above are true
336.
For normal mitochondria in the presence of an oxidizable substrate and an
uncoupler such as 2,4-dinitrophenol which do you expect?
A. Oxygen consumption even in the absence of ADP
B. A rise in temperature to dissipate energy that would otherwise have been used to
generate ATP
C. The flow of protons into the mitochondria matrix
D. * All of the above
E. None of the above
337.
How many ATP molecules are produced when FADH2 delivers electrons to the
electron transport system?
A. 1
B. * 2
C. 4
D. 36
E. 12
338.
How many ATP molecules can be derived from each molecule of acetyl CoA that
enters the Krebs’ Cycle?
A. 6
B. * 12
C. 18
D. 38
E. 39
339.
How many reactions of substrate-level phosphorylation are in an organism?
A. 2.
B.
C.
D.
E.
* 3.
4.
5.
12
340.
If heat energy is absorbed by the system during a chemical reaction, the reaction is
said to be:
A. At equilibrium
B. Endergonic
C. * Endothermic
D. Exergonic
E. Exothermic
341.
If the free energy change ?G for a reaction is -46.11 kJ/mol, the reaction is:
A. At equilibrium
B. Endergonic
C. Endothermic
D. * Exergonic
E. Exothermic
342.
In a fermentation metabolism, the organism produces ATP by
A. Generation of a proton motive force by transfer of electrons to oxygen
B. Substrate level phosphorylation
C. Oxidizing NADH to form the proton motive force
D. More than one of the above
E. * A, B, C
343.
In a system where temperature is uniform, free energy is ___
A. * The energy available to do work.
B. The extra energy emitted by the system
C. The total energy of the system
D. Kinetic energy.
E. Equivalent to entropy.
344.
In an electron carrier system, the net energy change is determined by the
difference in reduction potentials between the
A. Primary electron donor and the terminal electron donor.
B. Primary electron acceptor and the terminal electron acceptor.
C. Primary electron acceptor and the terminal electron donor.
D. * Primary electron donor and the terminal electron acceptor.
E. Secondary electron acceptor and the terminal electron acceptor
345.
In an exothermic chemical reaction
A. The mass of the products is greater than the mass of the reactants
B. The mass of the products is less than the mass of the reactants
C. * Heat is released as the reaction proceeds
D. Heat is absorbed as the reaction proceeds
E. None of the above
346.
In cellular metabolism, ATP provides energy by:
A. Releasing heat upon hydrolysis
B. Acting as a catalyst in chemical reactions
C. Stealing electrons from glucose and it’s intermediates
D. * Releasing a terminal phosphate group
E. Oxidizing helper molecules
347.
In normal mitochondria, the rate of NADH consumption (oxidation) will:
A. Be increased in active muscle, decreased in inactive muscle.
B. Be very low if the ATP synthase is inhibited, but increase when an uncoupler is
added.
C. Decrease if mitochondrial ADP is depleted.
D. Decrease when cyanide is used to prevent electron transfer through the
cytochrome a + a3 complex.
E. * All of the above are true.
348.
In order for a reaction to proceed from left to right as written
A. ATP must be involved in the reaction
B. A common intermediate must be formed
C. * The overall free-energy changes must be negative
D. A phosphate group must be transferred
E. All of the above
349.
In order to move molecules in your kidneys, your body needs _____.
A. * Energy
B. Sunlight
C. Cold
D. Heat
E. Only C and D
350.
In oxidative respiration, energy is harvested from glucose molecules in a sequence
of four major pathways. Which of the following is not one of these four pathways?
A. Krebs cycle
B. Glycolysis
C. Electron transfer through the transport chain
D. * Beta oxidation
E. Pyruvate oxidation
351.
In respiration, the final electron acceptor in the electron transport chain is _____.
A. Oxygen
B. ATP
C. Hydrogen ions
D. * H2O
E. CO2
352.
In the absence of oxygen, eukaryotic cells are restricted to
A. Chemiosmotic phosphorylation
B. Cyclic photo phosphorylation
C. Noncyclic photo phosphorylation
D. Oxidative phosphorylation
E. * Substrate level phosphorylation
353.
In the complete process of photosynthesis, the _____.
A. Kory cycle yields CO2
B. * Light reactions release oxygen
C. Calvin cycle breaks down H2O
D. Light reactions produce NADP+ from NADPH + H+
E. All of the above
354.
In the electron transport chain, the hydrogen ions enter the inner compartment of
mitochondria through special channels formed by
A. * ATP synthase.
B. Coenzyme A
C. Acetyl CoA.
D. Oxygen.
E. Water
355.
In the mitochondria NADH and QH2 are oxidized by ____________.
A. Carbon dioxide
B. Hydrogen peroxide
C. Ozone
D. * Oxygen
E. Water
356.
In the presence of oxygen and in the absence of ADP, what occurs if the
uncoupler 2,4-dinitrophenol is added to a suspension of normal mitochondria 5 minutes
after an oxidizable substrate has been added?
A. The substrate will be oxidized until the addition of the 2,4-dinitrophenol which
blocks further oxidation.
B. There is no effect; oxidation of the substrate continues at the same rate before and
after the addition of 2,4-dinitrophenol.
C. The substrate cannot be oxidized either with or without 2,4-dinitrophenol unless
ADP is also present.
D. * Oxidation of the substrate does not occur until the 2,4-dinitrophenol is added.
Afterward, oxidation proceeds rapidly until all of the substrate is consumed.
E. The substrate will be reduced until the addition of the 2,4-dinitrophenol which
blocks further reduction
357.
In theory at least, the free energy provided by NADH is sufficient to form
__________ ATP molecules.
A. 1
B. 2
C. 3
D. 4
E. * More than 4
358.
Instant source of energy is ___________.
A. Amino acids
B. Sucrose
C. * Glucose
D. Fats
E. Vitamins
359.
Intermediary metabolism is the term applied to reactions that _______________.
A. Degrade molecules
B. Synthesize large molecules such as proteins
C. Convert glucose to pyruvate
D. * Involve low molecular weight metabolites
E. Convert fats to fatty acid
360.
Levels of ATP and ADP are maintained in cells by
A. Phosphotransferases
B. Nucleoside diphosphate kinase
C. Adenylate kinase
D. Oxidative phosphorylation
E. * All of the above
361.
Most CO2 produced during aerobic cellular respiration is released during
A. Oxidative phosphorylation
B. Lactate fermentation.
C. * The Kreb’s cycle
D. Electron transport
E. Glycolysis.
362.
Most CO2 produced during aerobic cellular respiration is released during
A. Oxidative phosphorylation
B. Lactate fermentation
C. * The Kreb’s cycle
D. Electron transport
E. Glycolysis
363.
Most energy during cell respiration is harvested during
A. The Krebs cycle
B. * Oxidative phosphorilation
C. Glycolysis
D. Anaerobic respiration
E. Fermentation
364.
Most oxidation reactions in microbial bioenergetics involve the
A. * Removal of electrons and hydrogens
B. Addition of electrons and hydrogens
C. Addition of oxygen
D. Removal of oxygen
E. None of the above
365.
Organisms need a way of storing energy because _____.
A. A cell can't always immediately use all the energy it gets
B. An organism often has times when no energy is used
C. * A cell can release only stored energy
D. A cell cannot create energy and must get it from elsewhere in the organism
E. B and D
366.
Oxidative phosphorylation is regulated by:
A. The availability of reduced cofactors from catabolic pathways.
B. The availability of the dNTPs.
C. * The availability of ADP and Pi.
D. A and C
E. A, B, and C
367.
Oxidative phosphorylation requires all of the items listed below except
A. ATP synthase in the correct position in the membrane
B. Enzyme complexes embedded in a membrane
C. The flow of electrons from NADH and QH2 in the membrane
D. * A matrix more positively charged than the intermembrane space
E. A terminal electron acceptor which is O2 in mitochondria
368.
Phosphorylation at the expense of ATP is catalyzed by __________.
A. Protein kinases
B. Phosphoryl isomerases
C. Phosphatases
D. * All of the above
E. None of the above
369.
Regardless of the electron or hydrogen acceptor used, one of the products of
fermentation is always:
A. ADP
B. ATP
C. NAD+
D. Pyruvate
E. * Alcohol
370.
Respiration in addition to producing energy also carry out the function of
A. * Producing the major part of body heat
B. Manufacturing food
C. Maintaining water levels
D. None of the above
E. All the above
371.
Several prosthetic groups act as redox centers in Complex I, including:
A. FMN, ubiquinone, iron-sulfur clusters, heme.
B. * FMN, ubiquinone, iron-sulfur clusters.
C. Heme, ubiquinone, iron-sulfur clusters.
D. All of the above
E. None of the above
372.
Studying biogeochemical cycles would help a scientist learn how
A. Energy flows through an ecosystem
B. * Substances move in and out of living organisms
C. Chemicals react
D. Fatty acids are formed
E. A and B
373.
Substrate-level phosphorylation differs from oxidative phosphorylation in that:
A. Substrate-level phosphorylation involves the transfer of electrons
B. Substrate-level phosphorylation only occurs in the cytosol
C. Oxidative phosphorylation only occurs in the cytosol
D. * Oxidative phosphorylation involves the transfer of electrons
E. GTP is always involved in substrate-level phosphorylation
374.
The amount of energy recovered as ATP can be estimated by free energy of
hydrolysis of
A. Phosphoester I bond in ATP
B. Phosphoanhydride bonds in ADP
C. Phosphoester bond I ADP
D. * Phosphoanhydride bonds in ATP
E. All of the above
375.
The amount of energy required to bring all molecules to a reactive state prior to a
chemical reaction is called the reaction's _____________.
A. Free energy of formation
B. * Activation energy
C. Van der Waal's energy
D. Go'
E. More than one of the above is correct
376.
The chemical energy generated by oxidations cannot be captured by
A. NADH
B. NADP
C. FMN
D. FAD
E. * Q
377.
The chemiosmotic theory explains
A. The phosphorylation of ADP
B. The electron transport chain
C. The differences between inner and outer mitochondrial membranes
D. * The source of energy for formation of mitochondrial ATP
E. Aerobic respiration
378.
The coenzyme electron carriers produced in the Krebs cycle are
A. ATP and ADP
B. Pyruvate and acetyl CoA
C. * FADH2 and NADH
D. NAD and NADH
E. NADH and ATP
379.
The coenzymes NAD and FAD carry electrons to the
A. Nucleus
B. Citric Acid cycle
C. Plasma membrane
D. * Electron transport system
E. Lysosoms
380.
The degradation of which class of biochemicals does not significantly contribute
to the release of energy to cells?
A. * Nucleic acids
B. Proteins
C. Lipids
D. Carbohydrates
E. B and C
381.
The direct energy source that drives ATP synthesis during respiratory oxidative
phosphorylation is
A. Oxidation of glucose to CO2 and water
B. The thermodynamically favorable flow of electrons from NADH to the
mitochondrial electron transport carriers
C. Tthe final transfer of electrons to oxygen
D. * The difference in H+ concentration on opposite sides of the inner mitochondrial
E. membrane
F. Thermodynamically favorable transfer of phosphate molecules (from glycolysis
and Krebs cycle intermediates) to ADP
382.
The electron transport chain consists all of the following except
A. NADH dehydrogenase
B. Cytochrome complex
C. * Oxygenase
D. Cytochrome c oxidase
E. Ubiquinone, Q
383.
The electrons released by FADH2 during its oxidation to FAD by the electron
transport system finally end up as part of this molecule:
A. Glucose
B. * Water
C. Carbon dioxide
D. ATP
E. ADP
384.
The electrons that enter the electron transport system are carried there by
A. NADH
B. FADH2
C. * Both A and B
D. Biotin
E. PALP
385.
The energy for all forms of muscle contraction is provided by:
A. * ATP
B. ADP
C. Phosphocreatine
D. Oxidative phosphorylation
E. Generated in the mitochondria of the cell
386.
The energy in glucose cannot be released by _____.
A. Glycolysis
B. * Burning
C. Respiration
D. Photosynthesis
E. None of the above
387.
The energy produced during respiration is stored in
A. Pyruvic acid
B. Carbon dioxide
C. Adenosine monophosphate
D. * Adenosine triphosphate
E. Sialic acid
388.
The energy that is necessary to break bonds in the reactant molecules and form
new bonds in the products is called:
A. Delta E
B. * Activation energy
C. Transition state
D. Spontaneous energy
E. None of the above
389.
The enzyme complexes associated with oxidative phosphorylation and the
electron transport chain can be classified as ___________ proteins.
A. * Integral membrane
B. Peripheral membrane
C. Lipid-anchored membrane
D. Water-soluble
E. Both a and c
390.
The enzymes of the Krebs cycle are located in the
A. Cytoplasm
B. Inter-membrane space of mitochondria
C. Vesicles of the ER
D. Outer membrane of the mitochondria
E. *Matrix of the mitochondria
391.
The FADH2 formed during the TCA cycle enters the electron transport system at
which site?
A. NADH dehydrogenase
B. Cytochrome a
C. Coenzyme Q
D. ATP synthase
E. Cytochrome c1
392.
The final electron acceptor in the electron transport system is _____.
A. FADH2
B. * O2
C. Coenzyme Q
D. Cytochrome b
E. Cytochrome c
393.
The first law of thermodynamics states that
A. Energy is the capacity to do work.
B. Doing work is defined as causing movement against a resisting force
C. Heat flows from a warmer body to a cooler body
D. * Energy is neither created nor destroyed
E. All of the above
394.
The flow of material through a reaction pathway usually depends on
________________.
A. * Control at several steps in the pathway
B. Control of the first step of the pathway
C. Covalent modification of the enzyme that catalyzes the reaction
D. Feed-forward activation
E. Control of the second step of the pathway
395.
The formation of ATP from ADP and phosphate at the expense of the energy
yielded by electron transport to oxygen is called:
A. * Oxidative phosphorylation
B.
C.
D.
E.
Substrate-level phosphorylation.
Tissue respiration
Peroxidation
Krebs cycle
396.
The function of ATP is
A. * To provide energy for cellular processes
B. Catalyze chemical reactions
C. Make up long polymer chains
D. Store energy for a long time
E. Ingibit chemical reactions
397.
The hydrolysis of the highest energy phosphate bond(s) in which of the following
compounds will release the most free-energy?
A. Phosphoenolpyruurvate
B. ADP
C. AMP
D. ATP
E. * The energy generated by hydrolysis of the highest energy phosphate bond in all
of the above is about the same.
398.
The immediate energy source that drives ATP synthesis by ATP synthase during
oxidative phosphorylation is:
A. The flow of electrons down the electron transport chain.
B. * The H+ concentration gradient across the inner mitochondrial membrane.
C. The oxidation of glucose and other organic compounds.
D. The transfer of phosphate to ADP.
E. The affinity of oxygen for electrons.
399.
The inner mitochondrial membrane contributes to the formation of a proton
gradient mainly because it
A. Contains ATP synthase complex
B. Is the location of specific transporter proteins
C. * Is a barrier to protons
D. Is not rich in proteins
E. Is rich in proteins
400.
The loss of hydrogen is known as
A. Dehydration
B. Hydrogenation
C. Reduction
D. * Oxidation
E. Both D and D are correct
401.
The most important flavin-linked dehydrogenases in the mainstream of respiration
and electron transport, all localized in the:
A. ytosol
B. Nucleus
C. Rybosoms
D. * Mitochondria
E. Lysosoms
402.
The movement of protons through ATP synthase occurs from the
A. Matrix to the intermembrane space.
B. Matrix to the cytoplasm.
C. * Intermembrane space to the matrix.
D. Intermembrane space to the cytoplasm.
E. Cytoplasm to the intermembrane space.
403.
The notion that ATP is generated by a proton gradient existing across a membrane
is called
A. Proton motion.
B. * Chemiosmotic theory
C. Cytochromic flow
D. Lactate reduction
E. A and D
404.
The number of ATP molecules produced during aerobic and anaerobic respiration
are _____ and ________ respectively.
A. 2 and 38
B. 0 and 2
C. 38 and 0
D. * 38 and 2
E. 1-10
405.
The oxidation of a particular hydroxy substrate to a keto product by mitochondria
has a P/O ratio of less than 2. The initial oxidation step is very likely directly coupled to
the:
A. Oxidation of a flavoprotein
B. Oxidation of a pyridine nucleotide
C. * Reduction of a flavoprotein
D. Reduction of a pyridine nucleotide
E. Reduction of cytochrome a3
406.
The oxidizing agent in the enzyme superoxide dismutase is
A. Superoxide anion (.O2-)
B. H2O2
C. * Copper
D. O2
E. All of the above
407.
The oxygen utilized in cellular respiration finally shows up as
A. CO2
B. ATP
C. New O2
D. * H2O
E. Part of a sugar
408.
The part of the respiratory tract that is responsible for keeping it healthy is
________.
A. Trachea
B. Bronchi
C. Nasal cavity
D. * All the above
E. None of the above
409.
The process by which a cell is built up from the simple nutrients obtained from its
environment is called _____.
A. * Anabolism
B. Biosynthesis
C. Catabolism.
D. All of the above
E. More than one of the above, but not all
410.
The process by which the sun’s energy is trapped as the source of energy used by
virtually all living organisms?
A. Evolution
B. Metabolism
C. Adaptation
D. Homeostasis
E. * Photosynthesis
411.
The process complementary to respiration is __________.
A. Circulation
B. * Photosynthesis
C. Osmoregulation
D. Hydroregulation
E. None of the above
412.
The process shown is
A. Reduction and is endergonic
B. Reduction and is exergonic
C. Oxidation and is endergonic
D. Oxidation and is exergonic
E. A ang B
413.
The protonmotive force is a result of _______________________.
A. The flow of electrons from the matrix to the inner membrane space
B. * A combination of an electrical potential and a chemical potential
C. The flow of protons within the inner mitochondrial membrane
D. All of the above
E. None of the above
414.
The reaction, C6H6O6 + 6O2 = 6 CO2 + 6 H2O, when it occurs in living cells is
known as
A. * Aerobic fermentation
B. Anaerobic fermentation
C. Cellular respiration
D. Glycolysis
E. Oxidative phosphorylation
415.
The respiratory control center of humans is located in the
A. Blood-brain barrier
B. Alveoli
C. * Erythrocytes
D. Brainstem (medulla oblongata)
E. Trachea
416.
The respiratory exchange ratio (RER) is the ratio of:
A. * Volume of oxygen consumed _ volume of carbon dioxide produced
B. Volume of carbon dioxide produced _ volume of oxygen consumed
C. Volume of oxygen produced _ volume of carbon dioxide consumed
D. Volume of oxygen consumed _ body mass
E. Volume of oxygen consumed _ lung ventilation
417.
The role of oxygen in aerobic respiration is
A. To transport CO2
B. Most impotent in the Krebs cycle
C. To transport ekectrons in glycolysis
D. To provide electrons for the electron transport chain
E. * As the final hydrogen acceptor in the electron transport chain
418.
The sequence describing the flow of electrons in phagocytes producing
superoxide from oxygen is
A. O2 -> cytochrome b -> NADPH -> FADH
B. * NADPH -> FADH -> cytochrome b -> O2
C. NADH -> FADH -> cytochrome b -> O2
D. O2-> cytochrome b -> FADH -> NADPH
E. Cytochrome c -> cytochrome b -> NADPH -> FADH
419.
?The standard free energy (?G°') of ATP hydrolysis to ADP + Pi is about
A. +30 kJ/mol
B. +14 kJ/mol.
C. -14 kJ/mol.
D. * -30 kJ/mol.
E. -62 kJ/mol.
420.
The synthesis of one molecule of ATP from ADP requires _________ to be
translocated across the inner mitochondrial membrane.
A. One proton
B. * About two protons
C. Hundreds of protons
D. 1 mole of protons
E. 10 protons
421.
The term coupling in biochemistry can mean
A. Phosphorylating ADP along with the transport of electrons in mitochondria
B. Forming oxygen from superoxide anion
C. Linking reactions so that one cannot occur without the other
D. All of the above
E. * a and c
422.
The transfer of free energy from catabolic pathways to anabolic pathways is best
called
A. Feedback regulation
B. Bioenergetics
C. Cooperativity
D. * Energy coupling
E. Entropy
423.
The types of ‘work ‘ cells do include
A. Chemical workmaking and breaking bonds
B. Transport of nutrients into cells and waste products out
C. Movement of individual cells and stuff within a cell
D. Cells do not do work, only tissues do work
E. * A and c are correct
424.
Uncoupling of mitochondrial oxidative phosphorylation:
A. Allows continued mitochondrial ATP formation, but halts O2 consumption.
B. Halts all mitochondrial metabolism.
C. * Halts mitochondrial ATP formation, but allows continued O2 consumption.
D. Slows down the citric acid cycle.
E. Slows the conversion of glucose to pyruvate by glycolysis.
425.
What needs the nutrients and oxygen carried by your blood?
A. rgan systems
B. rgans
C. * issues
D. ndividual cells
E. Spesific cells
426.
What system transports oxygen and nutrients to the cells of your body?
A. The digestive system
B.
C. *
D.
E. A and D
427.
What tissue we used for the detection of cytochrome oxidase?
A.
B.
C.
D.
E.
Blood
* Spleen
Muscle
Liver
Heart
428.
What type of protein such as a channel protein cross the entire cell membrane?
A. Integral protein
B. Peripheral protein
C. * Transmembrane protein
D. Receptor protein
E. A and B
429.
What type of transport utilizes ATP?
A. * Active transport
B. Diffusion
C. Facilitated diffusion
D. Osmosis
E. Only B and C
430.
When 10,000 molecules of ATP are hydrolyzed to ADP and in a test tube, about
twice as much heat is liberated as when a cell hydrolyzes the same amount of ATP.
Which of the following is the best explanation for this observation?
A. Cells are less efficient at heat production than nonliving systems.
B. Cells convert some of the energy of ATP hydrolysis into other forms of energy
besides heat.
C. * Cells are open systems, but a test tube is a closed system.
D. The hydrolysis of ATP in a cell produces different chemical products than does
the reaction in a test tube.
E. The reaction in cells must be catalyzed by enzymes, but the reaction in a test tube
does not need enzymes.
431.
When a phosphate is transferred from a high-energy molecule of ADP to form
ATP it's referred to as _____.
A. Photophosphorylation
B. Substrate-level phosphorylation
C. * Oxidative phosphorylation
D. Citric cycle
E. Decarboxilation of pyruvat
432.
When O2 is reduced during the electron transport system, _____ is produced.
A. * H2O
B. CO2
C. ADP
D. Glucose
E. Pyruvat
433.
When the ?G'° of the ATP synthesis reaction is measured on the surface of the
ATP synthase enzyme, it is found to be close to zero. This is thought to be due to:
A. A very low energy of activation
B. Enzyme-induced oxygen exchange
C. Stabilization of ADP relative to ATP by enzyme binding
D. * Stabilization of ATP relative to ADP by enzyme binding
E. None of the above
434.
When xenobiotics are substrates for the protein called cytochrome P450, this
enzyme serves to
A. Provide oxidation
B. Solubilize natural metabolites
C. Solubilize steroids
D. * Solubilized drugs, anaesthetic, dyes and pesticides
E. All of the above
435.
Which has the highest reduction potential?
A. NADH
B. Complex I
C. Complex II
D. * O2
E. Cytochrom c
436.
Which is not generally a molecule used to conserve energy?
A. ATP
B. NADH
C. FAD
D. * QH2
E. All of the above
437.
Which is true for aerobic respiration but not true for anaerobic respiration?
A. CO2 is produced
B. ATP is produced
C. * Water is produced
D. Alcohol is produced
E. Pyruvate is produced
438.
Which is usually the slowest way to regulate a reaction in a metabolic pathway?
A. Allosteric modulation
B. Covalent modification
C. * Changing the enzyme concentration
D. All of the above are usually equally as fast
E. Competitive inhibitor
439.
Which metabolic pathway is common to both fermentation and cellular
respiration?
A. The Kreb’s cycle
B. Reduction of pyruvate to lactate
C. * Glycolysis
D. Synthesis of acetyl CoA from pyruvate
E. The electron transport chain
440.
Which molecule is an electron carrier that is carrying electrons?
A. NaCl
B. NAD+
C. * NADH
D. NH4
E. (NH4)2SO4
441.
Which of the following coenzymes would have to be continually present in the
cell in order for the oxidative reactions of glycolysis to continue?
A. FADH2
B. NADH
C. ATP
D. * NAD+
E. All of the above
442.
Which of the following is a coenzyme associated with cellular respiration?
A. NAD+
B. O2
C. FAD
D. * both A and C
E. PALP
443.
Which of the following is common to both cellular respiration and the light
reactions of photosynthesis?
A. The transfer of electrons to glucose
B. The chemiosmotic formation of ATP
C. * Oxygen is one of the byproducts
D. Mitochondria are essential organelles E. must have light
E. A and B
444.
Which of the following is correct concerning the mitochondrial ATP synthase?
A. It can synthesize ATP after it is extracted from broken mitochondria.
B. It catalyzes the formation of ATP even though the reaction has a large positive
?G'°.
C. It consists of F0 and F1 subunits, which are transmembrane (integral)
polypeptides.
D. It is actually an ATPase and only catalyzes the hydrolysis of ATP.
E. * When it catalyzes the ATP synthesis reaction, the ?G'° is actually close to zero.
445.
Which of the following is most similar in structure to ATP?
A. DNA helix
B. Phospholipid
C. RNA nucleotides
D. An anabolic steroid
E. * An amino acid with three phosphate groups attached
446.
Which of the following is not a factor contributing to the large free energy of
hydrolysis of ATP?
A. Electrostatic repulsion of oxygen atoms
B. Better solvation of products than ATP itself
C. * Complexes with Mg++ or Mn++ ions
D. Better stability of products than ATP itself
E. Electrical sheilding of products of hydrolysis
447.
Which of the following is not a part of adenosine diphosphate?
A. * Glucose
B. Adenine
C. Ribose
D. Two phosphate groups
E. All of the above
448.
Which of the following is true for all exergonic reactions?
A. A net input of energy from the surroundings is required for the reactions to
proceed.
B. The products have more total energy than the reactants.
C. The reactions are nonspontaneous.
D. * The reaction proceeds with a net release of free energy.
E. The reactants have more total energy than the products
449.
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. A net input of energy from the surroundings is required for the reactions to
proceed.
D. Some reactants will be converted to products.
E. The reactions are nonspontaneous.
450.
Which of the following is true for exergonic reactions?
A. The reactions upgrade the free energy in the products at the expense of energy
from the surroundings.
B. A net input of energy from the surroundings is required for the reactions to
proceed.
C. * The products have less free energy than the reactants.
D. The products have more free energy than the reactants.
E. Reactants will always be completely converted to products.
451.
Which of the following produced a product used for synthesis of subsrate-level
phosphorylation?
A. Phosphophructikinase
B. Aldolase
C. * Glyceraldehyd-3-phosphate dehydrogenase
D. 1,3 – bisphophoglycerate mutase
E. All of the above
452.
Which of the following reactions contains steps which require an input of ATP
before they can be completed?
A. * Glycolysis
B. Kreb’s cycle
C. Electron transport system
D. A and b
E. B and c
453.
Which of the following statements about energy conservation in the
mitochondrion is false?
A. Drug that inhibits the ATP synthase will also inhibit the flow of electrons down
the chain of carriers.
B. For oxidative phosphorylation to occur, it is essential to have a closed
membranous structure with an inside and an outside.
C. The yield of ATP per mole of oxidizable substrate depends on the substrate.
D. * Uncouplers (such as dinitrophenol) have exactly the same effect on electron
transfer as inhibitors such as cyanide; both block further electron transfer to
oxygen.
E. Uncouplers “short circuit” the proton gradient, thereby dissipating the proton
motive force as heat.
454.
Which of the following statements about the chemiosmotic theory is false?
A. Electron transfer in mitochondria is accompanied by an asymmetric release of
protons on one side of the inner mitochondrial membrane.
B. Energy is conserved as a transmembrane pH gradient.
C. Oxidative phosphorylation cannot occur in membrane-free preparations.
D. The effect of uncoupling reagents is a consequence of their ability to carry
protons through membranes.
E. * The membrane ATPase, which plays an important role in other hypotheses for
energy coupling, has no significant role in the chemiosmotic theory.
455.
Which of the following statements about the mitochondrial inner membrane is
(are) not true?
A. The inner membrane is permeable to CO2, H2O, and small ions.
B. The inner membrane contains about 75% protein.
C. * The inner membrane contains many respiratory proteins.
D. The inner membrane is highly invaginated.
E. All of the above are true
456.
Which of the following statements about the mitochondrial inner membrane is
(are) not true?
A. The inner membrane is permeable to CO2, H2O, and small ions.
B. The inner membrane contains about 75% protein.
C. The inner membrane contains many respiratory proteins.
D. The inner membrane is highly invaginated.
E. * All of the above are true
457.
Which of the following statements are true about oxidative phosphorylation?
A. Electron transport provides energy to pump protons into the intermembrane space.
B. * An electrochemical gradient is formed across the inner mitochondrial
membrane.
C. Potassium and sodium ions form an ionic gradient across the inner mitochondrial
membrane.
D. A and B
E. A, B, and C
458.
Which of the following statements are true about oxidative phosphorylation?
A. Electron transport provides energy to pump protons into the intermembrane space.
B. An electrochemical gradient is formed across the inner mitochondrial membrane.
C. Potassium and sodium ions form an ionic gradient across the inner mitochondrial
membrane.
D. * A and B
E. A, B, and C
459.
Which of the following statements is false?
A. Phosphofructokinase is the rate limiting enzyme in glycolysis
B. Phosphorylase activity is higher in Type II fibres than in Type I fibres
C. Endurance training increases the amount of TCA cycle enzymes in muscle
D. * Oxygen is consumed in the TCA cycle
E. The heart can oxidise lactate
460.
Which of the following statements is TRUE concerning catabolic pathways?
A. They build up complex molecules such as protein from simpler compounds.
B. They combine molecules into more complex and energy-rich molecules.
C. They are spontaneous and do not need enzyme catalysis.
D. They involve endergonic reactions that break complex molecules into simpler
ones.
E. * They are usually coupled with anabolic pathways to which they supply energy
in the form of ATP.
461.
Which of the following takes place during oxidative phosphorilation in
mitochondria
A. Protons are pumped from the matrix to the intermembrane space
B. Protons are pumped from the intermembrane space to the matrix
C. Electrons are pumped from the matrix to the intermembrane space
D. * Electrons are pumped from the intermembrane space to the matrix
E. NADP is pumped from the matrix to the intermembrane space
462.
Which of the following would be considered one of a cell's electron carriers?
A. ATP
B. * NADH
C. FAD
D. All of the above
E. More than one of the above, but not
463.
Which statement does not explain why many biochemical processes are carried
out via multi-step pathways rather than by single-step reactions (or only a few steps)?
A. Multi-step pathways allow for more control points to regulate biochemical
processes.
B. * The end products of most pathways can usually be produced only by the
pathway reactions that nature has evolved.
C. Sharing of intermediates between pathways is facilitated this way.
D. There is greater control over the amounts of energy that are consumed or released
at any one time.
E. None of the above
464.
Which statement is false about most metabolic pathways?
A. * Most pathways are reversible under physiological conditions.
B. Pathways serve to increase the efficiency of energy transfers.
C. The rates of pathway reactions vary to respond to changing conditions.
D. The enzymes that catalyze reactions in metabolic pathways generally catalyze
only a single step.
E. Most pathways are irreversible under physiological conditions.
465.
Which statement is not true about catabolic pathways?
A. They have a net release of energy.
B. They have a net consumption of ATP.
C. They liberate smaller molecules from larger ones.
D. They include the citric acid cycle.
E. A and C only
466.
Which statement is true about two reactions that are coupled?
A. * One reaction will normally not occur without the other.
B. One is always exergonic and the other is always endergonic.
C. Only oxidation-reduction reactions can be coupled.
D. Coupled reactions are always driven by the ATP to ADP conversion.
E. B and C
467.
Which sugar is a part of adenosine diphosphate?
A. Adenine
B. * Ribose
C. Glucose
D. Glycogen
E. Water
468.
Which term most precisely describes the general process of breaking down large
molecules into smaller ones?
A. Anabolism
B. Catalysis
C. * Catabolism
D. Dehydration
E. Metabolism
469.
Why is ATP an important molecule in metabolism?
A. It energizes other molecules by transferring phosphate groups
B. Its phosphate bonds are easily broken
C. Hydrolysis of its phosphate groups is endergonic
D. Hydrolysis of its phosphate groups is exergonic
E. * A, b, and d are correct
470.
Why is ATP an important molecule in metabolism?
A. It energizes other molecules by transferring phosphate groups
B. Its phosphate bonds are easily broken
C. Hydrolysis of its phosphate groups is endergonic
D. Hydrolysis of its phosphate groups is exergonic
E. * A, b, and c are correct
471.
Within the inner matrix of the mitochondrion are:
A. * The enzymes of the tricarboxylic acid cycle (Krebs’ cycle)
B. The components of the electron transport chain
C. Glycogen molecules
D. The enzymes of gluconeogenesis
E. The enzymes creatine kinase and carnitine acyl transferase 1
Real life situation questions
1. A competitive inhibitor of an enzyme
A. Increases Km without affecting Vmax
B. Decreases Km without affecting Vmax
C. * Increases Vmax without affecting Km
D. Decreases Vmax without affecting Km
E. All of above
2. A competitive inhibitor of an enzyme is usually:
A. A highly reactive compound
B. A metal ion such as Hg2+ or Pb2+
C. * Structurally similar to the substrate
D. Water insoluble
E. A poison
3. A holoenzyme refers to the form of the enzyme__________________.
A. * That has the cofactor attached
B. That does not have the cofactor attached
C. That is normally inactive
D. None of the above
E. That has only prosthetic group
4. A key role of the hydroxyl group at position 6 in the purine ring in the formation of a
transition state by the enzyme adenosine deaminase is obtained by comparing a _______
inhibitor and a _______ inhibitor.
A. Competitive; noncompetitive
B. Transition state analog; normal substrate
C. Noncompetitive; transition state analog
D. * Competitive; transition state analog
E. All of the above
5. A molecule that has the same shape as the substrate of an enzyme would tend to
A. speed metabolism by guiding the enzyme to its substrate
B. speed metabolism because it would also be a catalyst
C. * speed metabolism by acting as a cofactor for the enzyme
D. save the cell energy by substituting for the substrate
E. slow metabolism by blocking the enzyme’s active site
6. A molecule that has the same shape as the substrate of an enzyme would tend to
A. * Speed metabolism by guiding the enzyme to its substrate
B. Speed metabolism because it would also be a catalyst
C. Speed metabolism by acting as a cofactor for the enzyme
D. Save the cell energy by substituting for the substrate
E. Slow metabolism by blocking the enzyme’s active site
7. A person having deficiency of lactase cannot digest
A. Proteins
B. * Milk
C. Starch
D. Fats
E. Potatos
8. A pseudo-first order reaction____________________.
A. Is a two substrate reaction whose rate depends on the concentration of both
substrates
B. * Is a single substrate reaction whose rate depends on the concentration of that
substrate
C. Is two substrate reaction whose rate depends on the concentration of only one of
the substrate
D. Is two substrate reaction whose rate is independent of either substrate
E. Is a complex substrate reaction whose rate depends on the concentration of that
substrate
9. A reaction is designated as exergonic rather than endergonic when ___________.
A. Activation energy exceeds net energy release
B. Activation energy is necessary
C. No kinetic energy is released
D. * The potential energy of the products is less than the potential energy of the
reactants
E. It absorbs more energy
10. A(n) ______ does not bind to the active site of an enzyme
A. Substrate
B. Competitive inhibitor
C. * Allosteric effector
D. A and b
E. All of the above
11. Abzymes are
A. Immuno globulins
B. Isozymes
C. * Allosteric enzymes
D. Catalytic antibodies
E. Vitamins
12. According to the second law of thermodynamics, which of the following is true?
A. The total amount of energy in the universe is constant.
B. Energy conversions increase the order in the universe.
C. * The ordering of one system depends on the disordering of another.
D. The entropy of the universe is constantly decreasing.
E. All reactions produce some heat.
13. Acyl-group-transfer reactions often involve which coenzyme?
A. * Coenzyme A
B. NAD+
C. Cytochrome c
D. All of the above
E. None of the above
14. Allosteric centers serve as:
A. * The place of influence on the enzyme different regulator factors
B. The place relation of enzyme with substrate
C. Catalytic area
D. Contact area
E. The area seperetion of the spatially united amino acid residues
15. Allosteric enzymes _____________.
A. Usually have quaternary structure.
B. Do not behave according to Michaelis-Menton kinetics.
C. * Bind allosteric modulators at sites not associated with substrate binding.
D. Often have separate catalytic and regulator domains.
E. All of the above.
16. Allosteric enzymes______________.
A. * Follow Michaelis-Menton kinetics
B. Show hyperbolic plots when plotting [S] versus Vo
C. Are monomeric proteins
D. None of the above
E. Are oligomeric proteins
17. Among the following which is the Michaelis menten equation
A. V = Km + Vmax / (S)
B. V = Vmax ( S) / ( S) + Km
C. V = V max + (S) / (S)Km
D. V = V max (S) / Km
E. * V = V max Km/S
18. Among the following, which is the wrong statement regarding to competitive inhibition
A. * The inhibitor binds to active site of an enzyme
B. There is negligible inhibition at very high substrate concentration
C. There is an increase in Km
D. The enzyme is irreversibly inhibited by inhibitor
E. The inhibitor binds to allosteric site of an enzyme
19. An allosteric activator that affects Km but not Vmax does so by_____________.
A. Altering enzyme conformation to promote substrate binding
B. Altering enzyme conformation to increase Kcat
C. * Altering enzyme conformation to prevent binding of a competitive inhibitor
D. Altering enzyme conformation to prevent E+P
E. None of the above
20. An allosteric modulator influences enzyme activity by
A. Competing for the catalytic site with the substrate
B. * Binding to a site on the enzyme molecule distinct from the catalytic site
C. Changing the nature of the product formed
D. Covalently modifying enzyme
E. All of above
21. An enzyme is a special kind of catalyst that works to
A. * Speed up a specific biochemical reaction.
B. Slow down a chemical reaction
C. Break down chemical elements.
D. Maintain the correct temperature for a reaction
E. All answers are incorrect
22. An enzyme is specific. This means
A. It has a certain amino acid sequence
B. * It is found only in a certain place
C. It functions only under certain environmental conditions
D. It speeds up a particular chemical reaction
E. It occurs in only one type of cell
23. An enzyme without its required co-factor prosthetic group is referred to as
the____________________.
A. Cenzyme
B. Apoenzyme
C. * Holoenzyme
D. Izoensymes
E. None of the above
24. An inhibitor binds to a site other than the active site of the enzyme. Which statement
below correlates with this observation?
A. It must be a competitive inhibitor.
B. The inhibition must be irreversible.
C. * It could be noncompetitive or uncompetitive inhibition.
D. It could be irreversible, competitive, noncompetitive or uncompetitive. The data
do not relate to the type of inhibition.
E. None of above
25. An ion commonly found in metalloenzymes and which can undergo reversible oxidation
and reduction is
A. Ca++
B. Mg++
C. S=
D. * Fe++
E. All of the above
26. An uncompetitive inhibitor binds to _____.
A. E
B. * ES
C. P
D. A and b
E. A and c
27. An uncompetitive inhibitor of an enzyme catalyzed reaction
A. * Binds to the Michaelis complex (ES)
B. Decreases Vmax.
C. Is without effect at saturating substrate concentration
D. Can actually increase reaction velocity in rare cases
E. The first and second choices are both correct
28. At the beginning of an enzyme-catalyzed reaction the _________ is negligible.
A. Formation of ES
B. * Formation of E + P
C. Conversion of ES to E + S
D. Disappearance of ES
E. Formation of ES*FES**
29. Avidin, a protein found in egg whites binds tightly to which cofactor?
A. Pyridoxal phosphate
B. * Biotin
C. thiamin pyrophophosphate
D. Lipoamide
E. NAD(P)H
30. Because coenzymes are specific for the chemical groups that they accept and donate, they
are referred to as
A. Cofactors
B. Reactive centers
C. Activator ions
D. * Group-transfer reagents
E. All of the above
31. Both Vmax and Km values are altered in
A. Competitive inhibition
B. Noncompetitive inhibition
C. Uncompetitive inhibition
D. * All of these
E. Reversible
32. By enzymes with relative specificity can come project:
A. * Lipasa, proteases
B. Urease
C. Arginase, sucrase
D. Suktsinatdehydrogenase
E. Alkogol dehydrogenase
33. Cleland notations are used to graphically depict _______________________.
A. Allosteric enzyme kinetics
B. The binding order of substrates and the release order of products in a
multisubstrate reaction
C. Inhibition kinetics
D. * Michaelis Menton kinetics
E. None of the above
34. Coenzymes which must return to their original form after each catalysis are called
A. Prosthetic groups
B. Cosubstrates
C. Metabolite coenzymes
D. Vitamin coenzymes
E. * All of the above
35. Cysteine and serine residues can function in ___________ when present in the active site
of an enzyme.
A. Anion binding
B. Cation binding
C. Proton transfer
D. * Acyl group binding
E. All of the above
36. During feedback inhibition, the allosteric site is often the __________ enzyme in the
pathway.
A. Last
B. Least abundant
C. Most abundant
D. * First
E. Second
37. During the procedure using the turnip extract demonstrating the affect of inhibitors, what
was the enzyme studied?
A. * Peroxidase
B. Catalase
C. Catechol oxidase
D. Hydrogen peroxide
E. Oxidoreductase
38. Enzyme cofactors that bind covalently at the active site of an enzyme are referred to as
_________.
A. Cosubstrates
B. * Prosthetic groups
C. Apoenzymes
D. Vitamins
E. Isoenzymes
39. Enzymes
A. Enhance reaction rates
B. Are affected by pH
C. Act on specific substrates
D. Are affected by temperature
E. * All of the above
40. Enzymes fast up the velocity of a biochemical reaction by
A. * Increasing activation energy
B. Decreasing kinetic energy
C. Removing the functional group
D. Decreasing activation energy
E. All of the above
41. Enzymes increase the velocity of a reaction by___________________.
A. * Increasing the ground state energy of the substrate by forming the ES complex
B. Stabilizing the formation of the transition state
C. Altering the equilibrium of the reaction
D. A and b
E. All of the above
42. Enzymes lower the activation energy for biochemical reactions. They do this by
_______.
A. * Creating energy for use in the reactions they catalyze.
B. Forming a substrate-enzyme complex
C. Releasing energy which ultimately lowers the activation energy
D. Diffusion of Na and K through the Na-K pump
E. Always having a higher energy than the substrates
43. Enzymes that are activated by proteolytic cleavage are referred to as __________.
A. Covalently modified enzymes
B. Enzyme complexes
C. * Zymogens
D. Polymerized
E. Free radicals
44. Enzymes typically have _______ affinity for the substrate than for the transition state.
A. Lower
B. * Higher
C. The same
D. None of the above
E. All of the above
45. Exactly how do inhibitors affect the reaction rate of enzymes?
A. The extra energy would cause violent movement and collisions until the bonds in
the molecule broke, causing the shape to change.
B. The high concentration of hydrogen ions (H+) would break the bonds in the
molecule, causing the shape to change.
C. The high concentration of hydroxide ions (OH-) would break the bonds in the
molecule, causing the shape to change.
D. * Because the inhibitor molecules are structurally similar to the substrate
molecules, they slow down the chemical reaction.
E. The high concentration of hydrogen peroxide (H2O2) would break the bonds in
the molecule, causing the shape to change
46. Exactly how would an extremely low pH (less than 2.0) denature an enzyme?
A. The extra energy would cause violent movement and collisions until the bonds in
the molecule broke, causing the shape to change.
B. * The high concentration of hydrogen ions (H+) would break the bonds in the
molecule, causing the shape to change.
C. The high concentration of hydroxide ions (OH-) would break the bonds in the
molecule, causing the shape to change.
D. Because pH molecules are structurally similar to the substrate molecules, they
inhibit the chemical reaction.
E. All of above
47. Glucose + ATP > Glucose -6-phosphate + ADP. This reaction is catalysed by which of
the following enzyme classes
A. Oxidoreductase
B. * Transferase
C. Hydrolase
D. Lyase
E. Isomerases
48. Heterolytic carbon-carbon bond cleavage can result in the formation of_____.
A. Carbocation
B. * Radical species
C. Carbanion
D. A and b
E. A and c
49. How many active centers can have enzymes?
A. 1
B. 3
C. 2
D. * Depends on the amount of subunits of enzyme
E. 10
50. If a protein is reversibly denatured, which structural level can you be sure has remained
intact?
A. * Primary only
B. Secondary only
C. Tertiary only
D. Quaternary only
E. How sure do I have to be -?
51. If the absolute concentration of enzyme is unknown, which of the following values can
not be determined experimentally?
A. Km
B. kcat
C. * Vmax
D. None of the above
E. All of the above
52. If the substrate concentration in an enzyme catalyzed reaction is equal to 0.5 Km, the
initial reaction velocity will be
A. 0.25 Vmax
B. 0.33 Vmax
C. 0.50 Vmax
D. * 0.75 Vmax
E. 0. 15 Vmax
53. If the tertiary structure of an enzyme is changed _____.
A. Its substrate may not fit properly in the active site
B. It will be missing one of its polypeptides
C. * The helical coil will be stretched out
D. The product of the reaction will be a different molecule
E. Its substrate will bond covalently with the wrong part of the molecule
54. In a first order chemical reaction, the velocity of the reaction is proportionate to the
_____, while in a zero order reaction, the velocity of the reaction is proportionate to
_____.
A. Amount of enzyme; concentration of substrate
B. * Concentration of substrate; amount of enzyme
C. Concentration of substrate; the speed of the reaction
D. The speed of the reaction; concentration of substrate
E. All of the above
55. In an enzyme reaction involving one enzyme and one substrate, the rate of the reaction
depends on
A. Substrate concentration
B. Enzyme concentration
C. * Both substrate and enzyme concentrations
D. The enzyme concentration at first and the substrate concentration later on
E. Speed of reaction
56. In describing enzyme feature, enzymes:
A. Are composed primarily of polypeptides, which are polymers of amino acids
B. Can bind prosthetic groups such as metal ions that participate in enzyme reactions
C. Have defined structures.
D. * Bind their substrates at active sites
E. All statements are true
57. In describing the reaction rate for a chemical reaction, which of the following statements
about reaction rate is NOT true?
A. Reaction rate is the speed at which the reaction proceeds toward equilibrium.
B. * Reaction rate is governed by the energy barrier between reactions and products
C. Enzymes can accelerate the rate of a reaction
D. Reaction rates are not sensitive to temperature.
E. None of these
58. In formation of temporal complex between an enzyme and substrate important role
belongs chemical bonds, except:
A. Disulfide
B. Ion
C. * Peptid
D. Hydrogen bonds
E. Hydrophobic interaction
59. In understanding activation energy, activation energy is
A. * Energy that must be added to get a reaction started, which is recovered as the
reaction proceeds
B. Difference in energy between reactants and products
C. Energy that is lost as heat.
D. Free energy
E. Equal to the entropy times the absolute temperature
60. In which of the following do both examples illustrate kinetic energy?
A. * Positions of electrons in an atoma ball rolling down hill
B. Heatarrangement of atoms in a molecule
C. A rock resting on the edge of a cliffheat
D. A ball rolling down a hillheat
E. Lightarrangement of atoms in a molecule
61. In which of the following do both examples illustrate kinetic energy?
A. Positions of electrons in an atoma ball rolling down hill
B. Heatarrangement of atoms in a molecule
C. * A rock resting on the edge of a cliffheat
D. A ball rolling down a hillheat
E. Lightarrangement of atoms in a molecule
62. is known as _________ inhibition.
A. * Competitive
B. Uncompetitive
C. Uncompetitive
D. Feedback
E. Allosteric
63. Isoenzymes are generally separated by
A. Ion exchange chromatography
B. Gel filtration chromatography
C. Paper chromatography
D. * Electrophoresis
E. Selective adsorbtion
64. Km is _______.
A. The substrate concentration at ? Vmax.
B. = (k-1 + kcat)/k1
C. Related to an enzymes affinity for a specific substrate.
D. * The Michaelis Constant
E. All of the above
65. Km values are not altered by which type of inhibitor
A. * Competitive inhibitors
B. Non competitive inhibitors
C. Uncompetitive inhibitors
D. Allosteric inhibitor
E. All of these
66. Lactate dehydrogenase is a
A. Coenzyme
B. * Isoenzyme
C. Zymogen
D. Abzyme
E. Prostetic group
67. Michaelis constant Km is
A. Dependent on enzyme concentration
B. Independent of Ph
C. * Equal to substrate concentration that gives half Vmax
D. Numerically equal to half Vmax
E. Dependent on substrate concentration
68. Minerals and metals are often used in or as
A. Enzymes and coenzymes
B. * Coenzymes and cofactors
C. Cofactors and prosthetic groups
D. Coenzymes and prosthetic group
E. Prizes in the subcellular Olympics
69. Molybdenum is present in
A. Carboxypeptidase
B. Dinitrogenase
C. Pyruvate dehydrogenase
D. Pyruvate carboxylases
E. * Xantinoxidase
70. Most enzymes are composed of.
A. Lipids
B. Carbohydrates
C. * Proteins
D. Phosphates
E. Vitamins
71. Most enzymes are composed of.
A. Lipids
B. Carbohydrates
C. * Proteins
D. Phosphates
E. Vitamins
72. Name of enzyme which include zinc?
A. * Alkohol dehydrogenase
B. Cytochromoxidase
C. Xantinoksidase
D. Pyruvate dehydrogenase
E. Lactate dehydrogenase
73. Nicotinamide is ____________.
A. A co-substrate
B. A metabolite coenzyme
C. * A vitamin
D. A prosthetic group
E. None of the above
74. Noncompetitive inhibitor binds with
A. Active site
B. Allosteric site
C. Enzyme substrate complex
D. * Substrate
E. Product of reaction
75. Pyridoxal phosphate is involved in which type of reaction?
A. Oxidation of pyruvate
B. * Production of new amino acids by transamination
C. Phosphate-transfer to produce ATP from ADP
D. The regeneration of methionine from homocysteine
E. None of the above
76. Reaction order describes which of the following.
A. The order that substrates bind to the enzyme.
B. The order of reactions in a biosynthetic pathway
C. * How the velocity of a reaction is dependent on the concentration of specific
reactants.
D. All of the above
E. A and c
77. Role of coenzymes can active part vitaminesimillar substens. What matters does not act
part as coenzyme:
A. Ubiquinone
B. Lipoic acid
C. Carnitin
D. * Orotic acid
E. Pangamic acid
78. Some enzymes involved in the hydrolysis of ATP cannot function without help of sodium
ions. Sodium in this case functions as
A. A substrate
B. * A cofactor
C. An active site
D. A noncompetitive inhibitor
E. A vitamin
79. Some enzymes involved in the hydrolysis of ATP cannot function without help of sodium
ions. Sodium in this case functions as
A. A substrate
B. * A cofactor
C. An active site
D. A noncompetitive inhibitor
E. A vitamin
80. Substrate binding site on the enzyme is
A. * Active site
B. Allosteric site
C. Prostetic group
D. Cofactor
E. All of above
81. Temperature optimum of enzymes - is:
A. * Temperature which speed of enzymatic reaction is maximal
B. Temperature which is denaturation of enzymes
C. A size speed of reaction is at the temperature of 48-560С
D. The best conditions of bringing together are between an enzyme and substrate
E. Temperature which metabolic processes are inhibits
82. The active site of an enzyme
A. Remains rigid and does not change shape
B. Is found at the center of globular enzymes
C. Is complementary to the rest of the molecule
D. * Contains amino acids without sidechains
E. None of the above choices are correct
83. The activity of a zymogen is activated by____________.
A. Covalent modifications
B. Allosteric regulation
C. Association/disassociation of subunits
D. * Proteolytic modification
E. None of the above
84. The amino acid ________ can function in proton transfer when present in the enzyme
active site.
A. Glutamate
B. Aspartate
C. * Histidine
D. Lysine
E. All of the above
85. The apparent Km of an enzyme changes when the enzyme is treated with a_____.
A. Competitive inhibitor.
B. * Uncompetitive inhibitor.
C. Noncompetitive inhibitor
D. A and b.
E. B and c.
86. The coenzyme biotin is involved in the transferring of the following groups
A. Amino group
B. * CO2
C. One carbon group
D. Acyl group
E. Amino acid residues
87. The coenzyme present in isocitrate dehydrogenase
A. * NAD+
B. NADP+
C. FAD
D. TPP
E. Biotin
88. The coenzyme present in transaminase
A. NAD+
B. TPP
C. Coenzyme A
D. * Pyridoxal phosphate
E. Biotin
89. The enzyme Creatine kinase levels are increased in the blood of patients with
A. Prostate cancer
B. * Hepatitis
C. Heart attack
D. Osteoporosis
E. Muscle atonia
90. The enzyme involved in bone formation
A. * Acid phosphatase
B. Urease
C. Alkaline phosphatase
D. Calcitonin
E. Catalase
91. The enzyme kinase requires
A. * Mg
B. Mn
C. K
D. Mo
E. Сu
92. The enzyme which transfer groups between atoms within a molecule are
A. Recemases
B. Mutases
C. * Transferases
D. Oxido-reductases
E. All of these
93. The enzymes are inherent all physical and chemical properties of proteins, except:
A. High molecular mass
B. Breaking up to amino acid during a hydrolysis
C. Formation of colloid solutions
D. Antigen properties
E. * Stable is to influence of high temperatures and salts of heavy metals
94. The equilibrium constant for the conversion of the disaccharide sucrose to the simple
sugars glucose and fructose is 140,000. What can you conclude about the reaction:
sucrose + H2Ooglucose + fructose?
A. It is a closed system
B. It never reaches equilibrium
C. It is spontaneous, starting with sucrose
D. The equilibrium constant increases when the starting concentration of sucrose is
increased
E. * At equilibrium, the concentration of sucrose is much higher than the
concentrations of glucose and fructose.
95. The equilibrium constant for the ionization of acetic acid, is 0.00002. What can you
conclude about this reaction?
A. It is a closed system
B. * At equilibrium, the concentration of CH3COOH is much higher than the
concentrations of CH3COO- + H+.
C. It never reaches equilibrium.
D. It is spontaneous, starting with CH3COOH.
E. The equilibrium constant increases when the starting concentration of CH3COOH
is increased
96. The hydrophobic cleft in globular proteins which bind substrate molecules is called
A. The substrate pocket
B. The modulator site
C. The active site
D. The activity site
E. * The oligomeric site
97. The inactive precursor of an active enzyme is called
A. Zymogen
B. Ribozyme
C. Isozyme
D. * Abzyme
E. Nucleozyme
98. The inhibition of succinate dehydrogenase by malonate is an example for
A. * Competitive inhibition
B. Non competitive inhibition
C. Uncompetitive inhibition
D. Feedback or end product inhibition
E. None of these
99. The initial velocity assumption for Michaelis-Menton kinetic assumes that ______.
A. * The reaction is always running at Vmax.
B. The rate of E + P -> ES is negligible.
C. A large amount of product has formed.
D. K-2 is large.
E. None of the above.
100.
The initial velocity assumption of the Michaelis-Menton equation states that
__________.
A. * The rate of ES formation is equal to the rate of ES turnover
B. A large amount of product is formed
C. The rate of the P T ES reaction is negligible
D. a and b
E. b and c
101.
The ions of what metal contain porphirine coenzymes?
A. Na
B. * Fe
C. Zn
D. Mo
E. Mn
102.
The low value of Km indicates
A. High enzyme activity
B. High substrate affinity of enzyme
C. No effect on reaction
D. * Low affinity of enzyme with substrate
E. All of these
103.
The mechanism of enzyme action is _____.
A. To create an energy barrier between substrates
B. To lower the energy of the activation of a reaction
C. * To change the direction of thermodynamic equilibrium
D. To change endergonic into exergonic reactions
E. To allow substrates to move more freely in solution
104.
The non protein compound that acts as enzyme is
A. * DNA
B. RNA
C. Carbohydrate
D. Fat
E. Vitamins
105.
The noncompetitive inhibitor
A. Increases Vmax and Km
B. * Decreases Vmax
C. Increases Km without affecting Vmax
D. Decreases Km and Vmax
E. Increases Km
106.
The product(s) of lactate dehydrogenase under anaerobic conditions is (are)
A. Pyruvic acid
B. NAD+
C. NADH
D. A and b
E. * A and c
107.
The relationship between an enzyme and a reactant molecule can best be
described as:
A. A temporary association
B. An association stabilized by a covalent bond
C. * One in which the enzyme is changed permanently
D. A permanent mutual alteration of structure
E. Noncomplementary binding
108.
The role of zinc in the mechanisms of carbonic anhydrase is to
A. Maintain the configuration of the holoenzyme
B. Bind to three histidine residues
C. Produce a nucleophilic attack on the substrate
D. * Promote ionization of bound water
E. Produce an electrophilic attack on the substrate
109.
The rules are for each half-reaction:
A. Balance all elements except hydrogen and oxygen.
B. Balance oxygen by adding water (H2O(l)).
C. Balance hydrogen by adding H+(aq) ion
D. * Balance charge by adding electrons
E. Increase speed of reaction
110.
The specific activity of an enzyme is
A. The amount of enzyme that produces one mole of product per second under
standard conditions
B. The activity of an enzyme in relation to a standard preparation of the enzyme
C. The number of enzyme units per milligram of enzyme protein
D. * The activity of an enzyme in the presence of its preferred substrate
E. All of above
111.
The term given to the number of substrate molecules an enzyme can process per
second –
A. Reaction rate
B. * Michaelis constant
C. Optimal rate
D. Turnover rate
E. The substrate processing number
112.
The transition state of a catalyzed reaction (EX‡) is
A. * A highly-populated intermediate on the reaction pathway
B. Higher in energy than that of an uncatalyzed reaction
C. Lower in energy than that of an uncatalyzed reaction
D. Lower in energy than the reaction substrate
E. Bound very weakly to the catalyst
113.
The typical saturation curve for an enzyme catalyzed reaction is sigmoidal. This
indicates that the enzyme is
A. * A regulatory enzyme
B. A nonregularoty enzyme
C. Both
D. None
E. All of above
114.
The uncompetitive inhibitor binds with
A. Active site
B. Allosteric site
C. * Enzyme substrate complex
D. Substrate
E. Product of reaction
115.
Trypsin is a
A. * Exopeptidase
B. Endopeptidases
C. Carboxy peptidase
D. Phosphotransferase
E. Phosphopeptidase
116.
Unlike typical catalyzed reactions in organic chemistry enzyme reactions are
A. Usually stereospecific
B. Reaction specific
C. Essentially 100% efficient
D. Modulated to change activity levels.
E. * All of the above.
117.
Vmax ______________________.
A. Describes the velocity of reaction when substrate is bound to ? of the available
substrate binding sites on an enzyme
B. * Describes the velocity of reaction when all of the available substrate binding
sites on an enzyme are occupied by substrate
C. Is a rate constant for the reaction where the ES complex is converted to the E +
D. Is the value equal to one over the x intercept of a Lineweaver Burk plot.
E. B and d
118.
What component is not included in the structure of holoenzymes?
A. Apoenzyme
B. Coenzyme
C. Cofactor
D. Prostetic group
E. * Izoenzyme
119.
What distinguishes reversible inhibitors from irreversible inhibitors?
A. Reversible inhibitors are not covalently bound to enzymes but irreversible
inhibitors are.
B. There is an equilibrium between bound and unbound reversible inhibitor. There
usually is little back reaction for the binding of an irreversible inhibitor.
C. Reversible inhibitors are easier to purify from solutions of enzymes than
irreversible inhibitors.
D. * All of the above.
E. a and b only.
120.
What does appear common for enzymes with relative specificity?
A. * Action on the identical type of bonds of certain group of substrates
B.
C.
D.
E.
Ability to convert one substrate
Ability to influence on D - isomers
Influence on D- isomers, but does not influence on L- isomers
Action on a few types of bonds of certain group of substrates
121.
What feature is not commonly for all izoenzymes?
A. Action on the one substrate
B. Catalysis of identical reactions
C. Finding in different tissuers
D. * Electrophoretic mobility
E. Izoenzymes is typical for most enzymes, that in the structure have a few subunits
122.
What is the area of an enzyme called where the chemical reactions occur?
A. The Cytoplasm
B. * The Active Site
C. The Catalyst
D. The Nucleus
E. A substrate
123.
What method was the presence in the first time set by izoenzymes?
A. Dialysis
B. * Elektroforezis in the starched gael
C. Chromatography
D. Centrifugation
E. Rengen analysis
124.
What structure of proteins molecule is responsible for formation of active centre
and for his catalytic action?
A. Primary
B. * Tertiary
C. Secondary
D. Quaternary
E. None from following
125.
When considering the features of an exergonic reaction, exergonic reactions:
A. * Release energy
B. Are spontaneous reactions
C. Have an equilibrium constant greater than 1
D. Can be coupled to energonic reactions
E. All statements are true.
126.
When you plot [S] versus initial velocity for an allosteric enzyme, what type of
plot arises?
A. * Hyperbolic
B. Sigmoidal
C. Linear
D. Discontinuous
E. Exponential
127.
Which aminoacids residues does not enter in the composition of active center of
enzyme?
A. Serine
B. Cystein
C. Histidin
D. Thyrosin
E. * Arginine
128.
Which coenzyme is covalently bound to the enzyme active site?
A. NAD+/NADH
B. * Lipoamide
C. Coenzyme A
D. None of the above
E. Biotin
129.
Which coenzyme is likely involved in the reaction shown below?
A. * TPP
B. Biotin
C. Coenzyme A
D. FMN
E. NAD
130.
Which coenzyme links to a lysine residue in a protein's active site?
A. Biotin
B. Lipoic acid (lipoamide)
C. Pyridoxal phosphate
D. Biotin and pyridoxal phosphate only
E. * All three; biotin, lipoic acid and pyridoxal phosphate
131.
Which commonly involve some sort of mineral or metal?
A. Ligands and binding sites
B. Cofactors and prosthetic groups
C. * Coenzymes and cofactors
D. Ligands and prosthetic groups
E. Nasty scraping sounds
132.
Which enzymes do not enter in the complement of porphirine coenzymes?
A. Cytochrome b, с
B. Catalase
C. Peroxidase
D. * Phosphatase
E. Cytochrome а1, а
133.
Which of the following best describes the ability of an enzyme to convert the ES
complex to E + P?
A. * Vmax
B. Km
C. Kcat
D. Kcat/Km
E. All of the above
134.
Which of the following coenzymes functions in acyl transfer reactions?
A. NADPH
B. * Coenzyme A
C. Biotin
D. A and b
E. B and c
135.
Which of the following coenzymes participates in enzymatic mechanisms by
producing a free radical intermediate?
A. NADPH
B. Ubiquinone
C. Methylcobalamin
D. Biotin
E. * Lipoamide
136.
Which of the following is a property of a catalyst?
A. A catalyst can alter the equilibrium of a chemical reaction.
B. A catalyst is changed to a different form at the end of a reaction.
C. * A catalyst can increase the rate of a chemical reaction.
D. a and c
E. all of the above
137.
Which of the following is best used to determine how well a specific substrate is
used by a specific enzyme?
A. Km
B. * kcat
C. Vmax
D. kcat/ Km
E. ? Vmax
138.
Which of the following is true of enzymes that are regulated by allosteric
regulation?
A. * They are usually multimeric enzymes
B. A hyperobolic curve results from the plotting of Vo vs [S]
C. They behave according to Michaelis-Menton kinetics
D. A and b
E. B and c
139.
Which of the following kinetic parameters best describes the ability of a specific
substrate to bind to a specific enzyme?
A. Vmax
B. Km
C. Kcat
D. Kcat/Km
E. * All of the above
140.
Which of the following statements is FALSE?
A. Enzymes make reactions 103 to 1017 times faster.
B. Enzymes lower the amount of energy needed for a reaction.
C. * Enzymes are unchanged during a reaction.
D. Enzymes speed up the attainment of a reaction equilibrium.
E. Enzymes are proteins.
141.
Which of the following types of reactions will result in a hyperbolic plot when [S]
is plotted versus initial velocity?
A. Allosterically regulated reactions
B. Multi-step reactions
C. * Michaelis Menton reactions
D. A and c
E. All of the above
142.
?Which of the statements regarding enzymes is false?
A. Enzymes are proteins that function as catalysts
B. Enzymes are specific
C. * Enzymes provide activation energy for reactions
D. Enzyme activity can be regulated
E. Enzymes may be used many times for a specific reaction
143.
Which of these phrases best describes how enzymes affect chemical reactions?
A. Lower the activation energy
B. Raise the activation energy
C. * Supply activation energy
D. Remove activation energy
E. Could it have something to do with activation energy.?
144.
Which of these statements about enzyme inhibitors is true?
A. * A competitive inhibitor binds to the enzyme outside the active site.
B. The action of competitive inhibitors may be reversible or irreversible.
C. A noncompetitive inhibitor does not change the shape of the active site.
145.
146.
147.
148.
149.
150.
151.
D. When the product of an enzyme or an enzyme sequence acts as its inhibitor, this
is known as positive feedback
E. Antibiotics and pesticides generally do not act on enzymes, but rather affect the
genetic code of their victims
Which of these statements about enzyme inhibitors is true?
A. * A competitive inhibitor binds to the enzyme outside the active site
B. The action of competitive inhibitors may be reversible or irreversible
C. A noncompetitive inhibitor does not change the shape of the active site
D. When the product of an enzyme or an enzyme sequence acts as its inhibitor, this
is known as positive feedback.
E. Antibiotics and pesticides generally do not act on enzymes, but rather affect the
genetic code of their victims.
Which one of the following is an example of the second law of thermodynamics?
A. The aerobic respiration of glucose generates heat.
B. * All types of cellular respiration produce ATP.
C. CO2 is exhaled as a by-product of aerobic respiration.
D. Photosynthesis enables plants to create energy from sunlight.
E. Energy is stored during the Calvin cycle.
Which statement about enzyme catalyzed reactions is NOT true?
A. Enzymes form complexes with their substrates
B. Eenzymes lower the activation energy for chemical reactions.
C. Eenzymes change the Keq for chemical reactions.
D. * Many enzymes change shape slightly when substrate binds.
E. Reactions occur at the "active site" of enzymes, where a precise 3D orientation of
amino acids is an important feature of catalysis
Which statement about enzyme catalyzed reactions is NOT true?
A. Enzymes form complexes with their substrates
B. Enzymes lower the activation energy for chemical reactions
C. Enzymes change the K eq for chemical reactions
D. Many enzymes change shapes slightly when substrate binds
E. * Reactions occur at the "active site" of enzymes, where a precise 3D orientation
of amino acids is an important feature of catalysis
Which statement regarding enzyme function is true?
A. * Higher temperatures allow greater contact between enzymes and substrates;
therefore, the higher the temperature the better the enzyme will function.
B. Enzymes cannot function at a pH lower than 6.
C. Most coenzymes are inorganic substances such as ions of iron or potassium.
D. Excessive salt ions can cause an enzyme to denature.
E. All of the above.
Which statement regarding enzyme function is true?
A. Higher temperatures allow greater contact between enzymes and substrates;
therefore, the higher the temperature the better the enzyme will function.
B. Enzymes cannot function at a pH lower than 6.
C. Most coenzymes are inorganic substances such as ions of iron or potassium.
D. Excessive salt ions can cause an enzyme to denature.
E. * All of the above.
Which type of regulation occurs in the slowest time frame?
A. Regulation through covalent modification
B. Allosteric regulation
C. New synthesis of enzyme through gene induction
D. * Feedback regulation
E. None of the above
152.
Which type of specificity of enzymes does not existence?
A. Relative
B. Absolute
C. * Conformation
D. Space specificity
E. Stereospecificity
153.
Which vitamins does not appear as coenzymes?
A. B1
B. B2
C. B5
D. * С
E. B12
154.
Which would most likely not have much stereospecificity?
A. * Antibodies
B. Receptors
C. Enzymes
D. Codons
E. People who buy their components at Wal-Mart
155.
Why does heating interfere with the activity of an enzyme?
A. It kills the enzyme
B. It changes the enzyme’s shape
C. It decreases the energy of substrate molecules
D. * It causes the enzyme to break up
E. It decreases the chance that the enzyme will meet a substrate molecule
156.
Zinc is present in which of the following enzymes
A. Cytochrome oxidase
B. Arginase
C. Hexokinase
D. * Alcoholdehydrogenase
E. Catalase
157.
A 37 years old man was delivered to the hospital with symptoms of sharp
pancreatitis: vomiting, diarrhea, bradicardia, hypotension, weakness, dehydration of
organism. What preparation should be used for the treatment?
A. Ephedrine
B. * Kontrikal
C. Platifilin
D. No-spa
E. Etaperazin
158.
A 45 years old patient suffers from pain in lumbar department of the back and its
limited mobility. It is takes place darkening of urine with air. What inherited disease has
the patient?
A. Phenylketonuria
B. Galactosemia
C. * Alkaptonuria
D. Cystinosis
E. Syndrome of Fankoni
159.
A 45 years old patient suffers from pain in lumbar department of the back and its
limited mobility. It is takes place darkening of urine with air. What inherited disease has
the patient?
A. Phenylketonuria
B. Galactosemia
C. * Alkaptonuria
D. Cystinosis
E. Syndrome of Fankoni
160.
A 46 years old woman appealed to the doctor with complaints about pain in the
epigastrium after the fatty meal. Doctor suspected acute pancreatitis. Content of which
from the transferred substances in blood increased at this pathology?
A. Glucose
B. Aspartate amino transferase
C. Alanine amino transferase
D. * Amylase
E. Calcium
161.
A 47-years-old man was delivered to the hospital with the diagnosis –
myocardium infarction. What factions of LDH will prevail in the blood serum during the
first two days of disease?
A. LDH3
B. LDH2
C. * LDH1
D. LDH4
E. LDH5
162.
A 60-years-old man appealed to the doctor with complains of pain in a thorax. In
the blood serum were established increase of such enzymes activity: MB isoforms of
creatin phospho kinase, aspartate amino transpherase. About development of pathological
process in what organ or tissue do these changes testify?
A. In lungs
B. * In cardiac muscle
C. In skeletal muscles
D. In the liver
E. In smooth muscles
163.
A blood test was done in a biochemical laboratory with the diagnostic purpose for
a patient with the early stage of muscular dystrophy. Increase of activity of what enzyme
can be observed in this case?
A. Alanine aminotransferase
B. * Creatin kinase
C. Collagenase
D. Hyaluronidase
E. Glutaminase
164.
A child was delivered to a reanimation with such symptoms: vomit, diarrhea,
abnormal physical and mental development, cataract. Laboratory test showed
galactosemia. The deficiency of what enzyme does take place?
A. Galactokinase
B. UDP glucose-4-epimerase
C. * Hexose-1-phosphate-uridiltransferase
D. UDP- glucose –pyrophosphorilase
E. Glucose-6-phosphate dehydrogenase.
165.
A new-born child has diarrhea, vomiting and cataract. Disorder of synthesis of
what enzyme causes this disease?
A. * Galactose – 1 – phosphate uridyl transpherase
B. Glucose - 6 phosphatase
C. Hexokinase
D. Glycogen synthase
E. Glucose phosphate isomerase
166.
A new-born child has diarrhea, vomiting and cataract. Disorder of synthesis of
what enzyme caused this disease?
* Galactose – 1 – phosphate uridyl transpherase
Glucose - 6 phosphatase
Hexokinase
Glycogen synthase
Glucose phosphate isomerase
167.
A newborn suffers from the fatty degeneration of liver, takes place a galactosuria
and amino aciduria, increased level of total bilirubin in blood. What matter is it necessary
to exclude from the diet of child?
A. * Lactose
B. Fatty acids
C. Phenylalanine
D. Cholesterol
E. Saccharose
168.
A patient complains about acute stomach-ache, nausea, vomitting. Diastase
activity is 800 grammes/l hour What diagnosis is the most possible?
A. Acute cholecystitis
B. * Acute pancreatitis
C. Ulcer of stomach
D. Acute appendicitis
E. Enterocolitis
169.
A patient complains about acute stomach-ache, nausea, vomit. Diastase activity is
800 grammes/l•hour What diagnosis is the most possible?
A. Acute cholecystitis
B. * Acute pancreatitis
C. Ulcer of stomach
D. Acute appendicitis
E. Enterocolitis
170.
A patient complains about pain on the left side in breast, weakness and
tachycardia. What from the transferred enzymes is it necessary to define in blood for
confirmation of diagnosis of heart attack of myocardium?
A. * AsAT, CPK MB, LDH-1
B. AlAT, aldolase, LDH-4
C. Amylase, alkaline фосфатаза, ALAT
D. Acidic phosphatase, LDH-5, LDH-4
E. fetoprotein, aldolase, CK
171.
A patient has disorder of liver functions. Which from the below mentioned
biochemical indexes in blood is used for the estimation of the liver state?
A. * AlAT
B. LDH1
C. Creatin phosphokinase
D. Aldolase
E. Lipase
172.
A patient has metabolic acidosis. How will it change activity of intracellular
enzymes?
A. Activity of intracellular enzymes do not change substantially.
B. Activity of mitochondrial enzymes increased, activity of lysosomal enzymes
inhibited, which is accompanied the decline of catalytic processes
C. * Activity of mitochondrial enzymes is low, activity of lysosomal enzymes, which
will result in strengthening of catalytic processes, is increased
D. Total inhibition of all of tissue enzymes
E. Total activating of all of tissue enzymes
A.
B.
C.
D.
E.
173.
A patient has metabolic acidosis. How will it change activity of intracellular
enzymes?
A. Activity of intracellular enzymes does not change substantially
B. Activity of mitochondrial enzymes increases, activity of lysosomal enzymes
inhibits, which is accompanied the decline of catalytic processes
C. * Activity of mitochondrial enzymes is low, activity of lysosomal enzymes, which
will result in strengthening of catalytic processes, is increased
D. Total inhibition of all of tissue enzymes
E. Total activating of all of tissue enzymes
174.
A patient is found to be deficient in the enzyme galactose 1-phosphate
uridylyltransferase. Specifically due to this deficiency what might a doctor recommend?
A. avoid all strenuous exercise
B. eat a fat-free diet
C. increase intake of vitamin C
D. * avoid ingestion of milk and milk products
E. all of the above.
175.
A patient was delivered to a hospital. Possible diagnosis - acute pancreatitis. The
increase of activity of what enzyme can prove this disease?
A. Creatin kinase
B. Pepsin
C. Gastrixin
D. * Amylase
E. Aspartate transaminase
176.
A specific test on the damage of kidneys tissues for the proof of diagnosis inflammatory process in kidneys of the patient was conducted. This test is determination
in urine:
A. Concentrations of creatin
B. Activity of creatin phosphokinase MB
C. Presence of lactose
D. * Activity of transamidinase
E. Activity of pepsin
177.
A two years old child was delivered to the hospital with symptoms of mental and
physical underdevelopment, which suffers from the frequent vomiting after meal. In urine
found out phenyl-pyruvic acid. Disorder of which substances metabolism is this
pathology?
A. Phosphorus-calcium metabolism
B. Water-salt metabolism
C. * Metabolism of amino acids
D. Carbohydrates metabolism
E. Lipids metabolism
178.
A two years old child was delivered to the hospital with symptoms of mental and
physical underdevelopment, which suffers from the frequent vomiting after meal. In urine
found out phenyl-pyruvic acid. Disorder of which substances metabolism is this
pathology?
A. Phosphorus-calcium metabolism
B. Water-salt metabolism
C. * Metabolism of amino acids
D. Carbohydrates metabolism
E. Lipids metabolism
179.
Acute pancreatitis of the patient was diagnosed. Determination of which from the
below mentioned enzymes in blood can be a diagnostic criteria?
A. LDH
B.
C.
D.
E.
Aldolase
* Amylases
Creatin kinase
Alanine amino peptidase
180.
Acute pancreatitis was diagnosed after biochemical analyses. In order to avoid
autolysis of pancreas it is necessary to apply such preparations:
A. Complex of pancreatic enzymes
B. Insulin
C. * Inhibitors of proteolytic enzymes
D. Antibiotics
E. Sulfanilamides
181.
An acute pancreatitis and parotitis are diagnosed. How will it influence on the
activity of amylase in urine?
A. * High activity of amylase is in urine.
B. Low activity of amylase is in urine.
C. No any of amylase in urine.
D. No any changes.
E. All answers are correct.
182.
An acute pancreatitis and parotitis are diagnosed. How will it influence on the
activity of amylase in urine?
A. * High activity of amylase is in urine
B. Low activity of amylase is in urine
C. No any of amylase in urine
D. No any changes
E. All answers are correct.
183.
At an inspection In blood of the patient was found increase of enzymes activity:
creatin kinase, AsAT and LDH1, 2. What diagnosis is it possible in this case?
A. Muscular dystrophy
B. * Infarction of myocardium
C. Cirrhosis of liver
D. Disorders of CNS
E. Pancreatitis
184.
At the inspection of patient was diagnosed alkaptonuria. The deficiency of what
enzyme causes this pathology?
A. * Oxidase of homogentisic acid
B. Phenylalanine hydroxylase
C. Thyrosinase
D. Thyroxin hydroxylase
E. Mono amino oxidase
185.
At the inspection of patient was diagnosed alkaptonuria. The deficiency of what
enzyme causes this pathology?
A. * Oxidase of homogentisic acid
B. Phenylalanine hydroxylase
C. Thyrosinase
D. Thyroxin hydroxylase
E. Mono amino oxidase
186.
At the inspection of patient was found an increase of LDH activity in blood. It is
possible at the diseases of heart, liver, kidneys. What additional biochemical test should
be done for proper diagnostics?
A. Determination of sugar is in blood
B. * Determination of isoforms of LDH
C. Determination of ketone bodies level in blood
D. Determination of cholesterol level in blood
E. Determination of amylase in blood
187.
At treatment of bleeding wounds with a 3% hydrogen peroxide there forms a foam
due to decomposition of hydrogen peroxide with enzyme of blood. Choose this enzyme:
A. Monoaminooxidase
B. Carboanhydrase
C. Cytochromoxidase
D. * Catalase
E. Lactate dehydrogenase
188.
At treatment of bleeding wounds with a 3% hydrogen peroxide there forms a foam
due to decomposition of hydrogen peroxide with enzyme of blood. Choose this enzyme:
A. Monoaminooxidase
B. Carboanhydrase
C. Cytochromoxidase
D. * Catalase
E. Lactate dehydrogenase
189.
Cardiac muscle contains which of the following CK isoenzyme?
A. BB only
B. MM and BB only
C. MM, BB and MB
D. * MM and MB only
E. None of the above
190.
Diastase can be used for the hydrolysis can be used for the hydrolysis of
A. Sucrose
B. * Starch
C. Cellulose
D. Maltose
E. None of the above
191.
Enzymes of amnion liquid of 28 years old pregnant women weredetermined.
Insufficient activity of glucuronidase was detected. What pathological process is
possible?
A. Glycogenosis
B. * Mucopolysacharidosis
C. Aglycogenosis
D. Collagenosis
E. Lipidosis
192.
estimation will have the best predictive value?
A. Serum AST
B. Serum CK
C. Serum ALT
D. * Serum LDH
E. All of the above
193.
Festering wound was washed a with a hydrogen peroxide, but foam did not
appear. The possible reason of it is:
A. * Inherent absence of catalase
B. Too match of the rot in a wound
C. Small wound
D. A lack of iron in an organism
E. Lack of peroxydase
194.
For 18 years old patient with acute toxic hepatitis in the blood serum will be
enhanceable level:
A. * Alaninaminotransferase
B.
C.
D.
E.
Creatinkinase
Alkaline phosphatase
D-amilase
Lactate dehydrogenase-1 (LDH1)
195.
For a child which borned 2 days ago, observe the yellowing colour of skin and
mucus shells. Reason of such state can be a lack of enzyme:
A. * UDP-glyucuroniltransferase
B. Sulphontransferase
C. Hemshyntetase
D. Hemoxigenase
E. Biliverdinreductase
196.
For cleaning of festering wound and their rapid healing used immobilized trypsin
on bandaging material. What it advantage as for the native enzyme?
A. * Long term of action
B. Higher activity
C. Higher specificity of action
D. Higher sensitivity to the temperature
E. Higher sensitivity to the changes of рН
197.
For cleaning of festering wound pharmaceutical enzymes preparations are used.
Specify what matter will be effective for cleaning from necrotizing tissues and wounds
healing :
A. Washing with glucose oxidase
B. * Applications with Trypsin
C. Washing with a hydrogen peroxide
D. Imposition of sterile bandages
E. Imposition of bandages with NaCl
198.
For diagnostic of acute inflammatory process in kidneys was conducted a specific
test - determination in urine of such substance:
A. Content of lactose
B. Activity of creatinkinase
C. Concentrations of creatin
D. Activity of pepsin
E. * Activity of alanine amino peptidase
199.
For dissolving of scars, compressions, hematomas, the easier transport of
medications in tissues such enzyme is used:
A. Trypsin
B. Ribonuclease
C. * Hyaluronidase
D. Plasmin
E. Pepsin
200.
For the patient with respiratory infection sulphanylamide preparation
(sulphodimetoxin) was recommended. What mechanism of action of this preparation:
A. * Competitive inhibition of enzymes of folic acid formation from Para-amino
benzoic acid of microorganisms
B. Inhibition of translation of bacterial proteins.
C. Noncompetitive inhibition of viral cytochrome oxydase.
D. Inhibition of transcription initiation
E. Irreversible inhibition of viruses replication.
201.
For treatment of dermatitises, wounds and ulcers which heal badly are used
coenzyme preparations of flavin mononucleotide and flavinate. The active forms of
which vitamin are they?
A. B1
B.
C.
D.
E.
* B2
B5
B3
C
202.
For treatment of dermatitises, wounds and ulcers which heal badly used
coenzymes preparations of flavin mononucleotide and flavinate. The active forms of
what vitamin are they?
A. * B2
B. B1
C. B5
D. B3
E. C
203.
For treatment of the patient with acute pancreatitis a doctor prescribed a trasilol.
For what purpose used this preparation?
A. * To avoid of autolysis of pancreas
B. For the improvement of fats digestion
C. For the improvement of proteins digestion
D. For the increase of insulin secretion
E. All above are correct
204.
From the human blood serum were selected and discovered properties of five
isoenzyme forms of lactate dehydrogenase. What property of isoenzyme does prove that
the selected forms are the same enzyme?
A. Same molecular mass
B. * Catalyze the same reaction
C. Same physical and chemical properties
D. Tissue localisation
E. Same electrophoretic mobility
205.
Hairs, skin and eyes of a patient do not have a pigment. A diagnosis – albinism
was set. The deficiency of what enzyme does take place?
A. * Tyrosinase
B. Arginase
C. Carbanhydrase
D. Histidin decarboxylase
E. Aldolase
206.
In a stomach of new-born takes place transformation of soluble of milk proteins caseins into insoluble protein - paracasein with participation of calcium ions and enzyme.
What enzyme does take part in this process?
A. * Rennin
B. Pepsin
C. Gastrin
D. Secretin
E. Lipase
207.
In an organism was found the lack of iron. It will cause the decrease of such
enzyme activity:
A. Glutation peroxidase
B. Carboanhydrase
C. Carboxypeptidase
D. Ceruloplasmin
E. * Catalase
208.
In an organism was found the lack of copper. It will cause the decrease of such
enzyme activity:
A. Cytochrome b
B.
C.
D.
E.
Glucose oxidase
Catalase
* Cytochrome oxsidase
Glutation peroxidase
209.
In blood and urine of a patient it was takes place increase value of pyruvic and
ketoglutaric acids. The deficiency of which coenzyme causes these changes?
A. Pyridoxal phosphate
B. * Thiamin pyrophosphate
C. Flavin mononucleotide
D. Biotin
E. Ubiqinon
210.
In blood and urine of a patient it was takes place increase value of pyruvic and ?ketoglutaric acids. The deficiency of which coenzyme causes these changes?
A. Pyridoxal phosphate
B. * Thiamin pyrophosphate
C. Flavin mononucleotide
D. Biotin
E. Ubiqinon
211.
In blood of a patient were found out the decline of activity of amino transferases
and decarboxylases of amino acids. Which coenzyme preparation may be recommended
for this patient?
A. Thiamin pyrophosphate
B. FAD
C. * Pyridoxal phosphate
D. NAD
E. Ubiqinon
212.
In blood of patient found out the increase of activity of LDH1, LDH2, AsAT,
creatin phosphokinase - MB. In what organ disorders of biochemical processes takes
place?
A. Pancreas
B. Skeletal muscles
C. Kidneys
D. Liver
E. * Heart
213.
In bloodof the patient concentration of acetaldehyde is increased, and causes
disgust of an alcohol. What preparation - the inhibitor of aldehyde dehydrogenase is used
in medical practice for the prophylaxis of alcoholism?
A. Ethanol.
B. * Teturam.
C. Trasilol
D. Aldehyde
E. Methanol
214.
In medical practice for treatment of festering wound enzymes preparations are
used. Which from the below mentioned enzymes is used in such cases?
A. * Trypsin
B. Alkaline phosphatase
C. Acidic phosphatase
D. Amylase
E. Arginase
215.
In poison of some snakes there is an enzyme which in a human organism can
result in formation of substances with a hemolytic action. Choose it.
A. * Phospho lipase A2
B.
C.
D.
E.
Lipase A1
Lipase C
Phospho lipase D
Phospho lipase B
216.
increase in which of the LDH isoenzyme fraction?
A. LDH-1
B. LDH-1 and LDH-2
C. * LDH-3 and LDH-4
D. LDH-2 and LDH-3
E. LDH-5
217.
It was determinate high activity of amylase in a patient’s saliva . How properly
interpret this analysis?
A. * ParotitisIt is possible.
B. Pathology of liver.
C. This analysis testifies disorders of gastrointestinal tract.
D. It is possible at nephropathies
E. This analysis testifies disorders of carbohydrate metabolism in an organism.
218.
It was determinate high activity of amylase in urine of a patient. How properly
interpret this analysis?
A. * It is possible acute pancreatitis, parotitis.
B. Pathology of liver.
C. This analysis testifies disorders of gastrointestinal tract.
D. It is possible at nephropathies
E. This analysis testifies disorders of carbohydrate metabolism in an organism.
219.
It was determine high activity of amylase in urine of a patient. How properly
interprete this analysis?
A. * It is possible acute pancreatitis, parotitis.
B. Pathology of liver.
C. This analysis testifies disorders of gastrointestinal tract.
D. It is possible at nephropathies
E. This analysis testifies disorders of carbohydrate metabolism in an organism.
220.
It was established that at parodontitis the secretion of kallikrein is increased.
Choose, what does increase inflammatory reaction in an oral cavity as result the of this
enzyme action?
A. Trasilol
B. * Kinins
C. Secretory immunoproteins
D. Lysozyme
E. Factor of nerves growth
221.
New antibiotics are synthesized with fermentative transformations of natural
antibiotics. What from the below named forms of enzymes are widely used in
pharmaceutical industry?
A. * Immobilized enzymes
B. Native enzymes
C. Denaturized enzymes
D. Complex of enzyme with a coenzyme
E. Complex of enzyme with an activator
222.
On which day following acute myocardial infarction the estimation of serum AST
willbe of greatest significance?
A. First day
B. * Second day
C. Third day
D. Fourth day
E. None of the above
223.
Organism suffers from hypovitaminosis of B5. How will it change the function of
oxidoreductases?
A. It will inhibit synthesis and functions of cytochroms
B. It will inhibit synthesis and functions of FMN and FAD – dependent
dehydrogenases
C. It causes improper synthesis and functions of TPP, which is the coenzyme of
pyruvate dehydrogenase.
D. It causes inhibition of synthesis and functions of aminotransferases.
E. * It causes inhibition of synthesis and functions of NAD and NADP – dependent
oxidoreductases (dehydrogenases)
224.
Parotitis of the patient was diagnosed. Determination of which from the below
mentioned enzymes in blood can be a diagnostic criteria?
A. LDH
B. Aldolase
C. * Amylases
D. Creatin kinase
E. Alanine amino peptidase
225.
released in plasma?
A. Kidney, R.B.C and Liver
B. * Heart, Kidney and R.B.C
C. Heart, Kidney and Liver
D. Heart, Lungs and Brain
E. All of the above
226.
Salivary amylase is an enzyme in humans that breaks down starch. The optimum
pH for this reaction is 6.7. The rate of this reaction would not be affected by
A. * Maintaining the pH of the reaction at 6.7
B. Substrate concentration
C. Enzyme concentration
D. Decreasing the temperature of the reaction by 5oC
E. Maintaining the pH of the reaction at 7.7
227.
Teturam which is the inhibitor of aldehyde dehydrogenase used in medical
practice for the prophylaxis of alcoholism. An increase in blood of what metabolite
causes disgust of an alcohol?
A. malonic aldehyde
B. Ethanol
C. * Acetaldehyde
D. Proponic aldehyde
E. Methanol
228.
The analysis demonstrated a 10 times increase of diastase activity. The danger of
autolysis of a patient’s pancreas caused with activating of enzyme:
A. Amylase
B. Pepsin
C. * Trypsin
D. Lipase
E. Nuclease
229.
The analysis demonstrated a 10 times increase of diastase activity. The danger of
autolysis of a patient’s pancreas caused with activating of enzyme:
A. Amylase
B. Pepsin
C. * Trypsin
D. Lipase
E. Nuclease
230.
The functional state of liver, effectiveness of treatment and prognosis of disease
development, estimate by such biochemical indexes of blood and urine, except:
A. AlAT
B. Gamma-glutamintranspeptidase
C. Alkaline phosphatase
D. Contents of albumins and globulins
E. * Diastase
231.
?The inherited genetic defects result in violation of synthesis of some enzymes in
the human organism. The defect of which enzyme results in disorders of splitting of
lactose:
A. * Lactase
B. Maltase
C. Sucrase
D. Amylase
E. Peptidase
232.
The patient with cyanide poisoning was delivered to clinic. What mast be
immediately used for the improvement of his state?
A. Glucose
B. Ascorbic acid
C. * Cytochromoxidase
D. Vitamin B1
E. Nicotine amide
233.
The рН of children’s gastric juice is of 4,0-5,0. Name the enzyme of gastric juice
which is active in this conditions.
A. * Rennin
B. Pepsin
C. Trypsin
D. Elastase
E. Chymotrypsin
234.
Trypsin
A. * Arginase
B. Catalase
C. Alkaline phosphatase
D. Acidic phosphatase
235.
Viral hepatitis of a 5 years old child is suspected. Which from below mentioned
indexes is it necessary to define for confirmation of diagnosis?
A. LDH2
B. LDH1
C. AsAT
D. * AlAT
E. Creatin kinase
236.
Vomiting, diarrhea after consuming milk, enlargement of the liver, jaundice,
cirrhosis,cataracts, retardation of the mental development, elevated blood-galactose level,
absence of the galactose 1-phosphate uridyl transferase in red blood cells are the
symptoms of:
A. lactose intolerance
B. hypolactasia
C. * galactosemia
D. all of the above
E. diabetes mellitus
237.
With ageing in cartilaginous decreases intensity of proteoglycans formation that
leads to diminishing of degree of their hydratation and loss of tissues turgor. Activity of
what enzymes of lysosomes does increase?
A. Deaminase, decarboxylase
B. Isomerase, dehydrogenases
C. Protease, lipase
D. Oxidoreductases, phosphstase
E. * Cathepsins, glycosidase
238.
With urine of newborn was done a reaction with FeCI3 and a positive reaction
(dark color) got. What disease is possible?
A. Galactosemia
B. Tirosinosis
C. * Phenylketonuria
D. Alkaptonuria
E. Aminoaciduria.
239.
With urine of newborn was done a reaction with FeCI3 and a positive reaction
(dark color) got. What disease is possible?
A. Galactosemia
B. Tirosinosis
C. * Phenylketonuria
D. Alkaptonuria
E. Aminoaciduria
240.
A reaction can occur spontaneously only if G, the change in free energy of
products and reactants, is:
A. positive;
B. * negative;
C. 0;
D. all reactions can occur spontaneously.
E. all of the above.
241.
All of the following compounds are intermediates of TCA cycle except
A. Malate
B. * Pyruvate
C. Oxaloacetate
D. Fumarate
E. ?-Ketoglutarate
242.
An aneplerotic reaction which sustains the availability of oxaloacetate is the
carboxylation of
A. Glutamate
B. * Pyruvate
C. Citrate
D. Succinate
E. All of the above
243.
If all the enzymes, intermediates and cofactors of the citric acid cycle as well as
an excess of the starting substrate acetyl-CoA are present and functional in an organelle
free solution at the appropriate pH, which of the following factors of the citric acid cycle
would prove to be rate limiting?
A. Molecular oxygen
B. Half life of enzyme
C. Turnover of intermediates
D. * Reduction of cofactors
E. All of theese
244.
In TCA cycle, oxalosuccinate is converted to ?-ketoglutarate by the enzyme:
A.
B.
C.
D.
E.
Fumarase
* Isocitrate dehydrogenase
Aconitase
Succinase
?-ketoglutarate dehydrogenase
245.
Most of the metabolic pathways are either anabolic or catabolic. Which of the
following pathways is considered as “amphibolic” in nature?
A. Glycogenesis
B. Glycolytic pathway
C. Lipolysis
D. * TCA cycle
E. All of these
246.
Out of 24 mols of ATP formed in TCA cycle, 2 molecules of ATP can be formed
at “substrate level” by which of the following reaction ?
A. Citric acid>?Isocitric acid
B. Isocitrate>?Oxaloacetate
C. Succinic acid>?Fumarate
D. * Succinyl>?Succinic acid
E. Both A and D
247.
Pyruvate dehydrogenase contains all except
A. * Biotin
B. NAD
C. FAD
D. CoA
E. Lipoic acid
248.
The enzyme ?-ketoglutarate dehydrogenase in the citric acid cycle requires
A. * Lipoate
B. Folate
C. Pyridoxine
D. Inositol
E. NADP
249.
The reaction catalysed by ?-ketoglutarate dehydrogenase in the citric acid cycle
requires
A. * NAD
B. NADP
C. ADP
D. ATP
E. PLP
250.
A distinct set of metabolic reactions is called a reaction ________________.
A. Network
B. Cycle
C. * Pathway
D. Mechanism
E. A and B
251.
A specific inhibitor for succinate dehydrogenase is
A. Arsinite
B. * Melouate
C. Citrate
D. Cyanide
252.
A specific inhibitor for succinate dehydrogenase is
A. Arsinite
B. * Malouate
C. Citrate
D. Cyanide
E. All of these
253.
Acetyl CoA _________ pyruvate dehydrogenase complex and NADH
__________ it.
A. activates; activates
B. activates; inhibits
C. * inhibits; inhibits
D. inhibits; activates
E. nome of the above
254.
Acetyl CoA _________ pyruvate dehydrogenase complex and NADH
__________ it.
A. activates; activates
B. activates; inhibits
C. * inhibits; inhibits
D. inhibits; activates
E. nome of the above
255.
Aerobic oxidation of pyruvate to CO2 and H2O results in formation of molecules
ATP:
A. 38 ATP
B. 12 ATP
C. 3 ATP
D. * 15 ATP
E. 2 ATP
256.
After passing through the citric acid cycle, one mole of pyruvate will result in the
formation of ______ moles of carbon dioxide and _________ mole(s) of ATP (or GTP).
A. 2; 2
B. 2; 1
C. 3; 2
D. * 3; 1
E. 1; 3
257.
All enzymes and coenzymes of the pyruvate dehydrogenase complex are located
in:
A. cytoplasm;
B. * matrix of mitochondria;
C. lysosomes;
D. partially in cytoplasm, partially in mitochondrial matrix.
E. all of the above
258.
All of the following are allosteric enzymes except
A. Citrate synthetase
B. ?-Ketoglutarate dehdrogenase
C. * Succinate thiokinase
D. Succinate dehydrogenase
E. Both B and C
259.
All of the following are intermediates of citric acid cycle except
A. Oxalosuccinate
B. Oxaloacetate
C. * Pyruvate
D. Fumarate
E. ?-Ketoglutarate
260.
All of the following intermediates of citric acid cycle can be formed from amino
acids except
A.
B.
C.
D.
E.
?-Ketoglutarate
Fumarate
* Malate
Oxaloacetate
B and C
261.
Allosteric effector of enzymes of Krebs cycle which stimulate their oxidation is:
A. Succinate
B. * NAD+
C. NADH2
D. ATP
E. FADH2
262.
Allosteric effector of enzymes of Krebs cycle which stimulate their oxidation is:
A. Succinate
B. * NAD+
C. NADH2
D. ATP
E. FADH2
263.
An allosteric enzyme responsible for controlling the rate of T.C.A cycle is
A. Malate dehydrogenase
B. * Isocitrate dehydrogenase
C. Fumarase
D. Aconitase
E. All of the above
264.
An allosteric enzyme responsible for controlling the rate of T.C.A cycle is
A. Malate dehydrogenase
B. * Isocitrate dehydrogenase
C. Fumarase
D. Aconitase
E. Both A and B
265.
An amphibolic pathway among the following is
A. HMP shunt
B. Glycolysis
C. * Citirc acid cycle
D. Gluconeogenesis
E. All of these
266.
An aneplerotic reaction which sustains the availability of oxaloacetate is the
carboxylation of
A. Glutamate
B. * Pyruvate
C. Citrate
D. Succinate
E. Lactate
267.
An enzyme of the citric acid cycle also found outside the mitochondria is
A. Isocitrate dehydrogenase
B. Citrate synthetase
C. * ?-Ketoglutarate dehydrogenase
D. Malate dehydrogenase
E. All of the above
268.
Anabolic and catabolic reactions in eukaryotes can occur simultaneously in cells.
This is possible because _______.
A. they all occur in the cytosol
B. the anabolic and catabolic pathways do not share any intermediate metabolites
C. * of the compartmentation of metabolites for the reactions of the opposing
pathways
D. all catabolic reactions are exergonic and all anabolic reactions are endergonic
E. they all occur in the mitochondria
269.
Carbons from acetyl CoA are transferred to the citric acid cycle. Which is the first
round of the citric acid cycle that could possibly release a carbon atom originating from
this acetyl CoA?
A. first round
B. * second round
C. third round
D. fourth round
E. fifth round
270.
Catabolism is a form of metabolism in which molecules are converted into
A. * Simple end product, energy
B. Large start product
C. Peptides, protein
D. Food, storage
E. All of the above
271.
Catabolism is characterized by _______________ of three major routs toward a
final common pathway.
A. divergence;
B. * convergence;
C. splitting;
D. none of the above.
E. all of the above.
272.
Central intermediate product of all of metabolism is:
A. * Acetyl-CoA
B. Succinyl-CoA
C. Oxaloacetate
D. Pyruvate
E. Citrate
273.
Citrate has a positive allosteric effect on which one of the following enzymes?
A. Pyruvate kinase
B. * Acetyl CoA carboxylase
C. Phosphofructokinase
D. Fatty acid synthetase
E. Enolase
274.
Citrate is converted to isocitrate by aconitase which contains
A. Ca++
B. * Fe++
C. Zn++
D. Mg++
E. Both A and B
275.
Citrate is converted to isocitrate by aconitase which contains
A. Ca++
B. * Fe++
C. Zn++
D. Mg++
E. All of the above
276.
Cofactors of dehydrogenases are all, except one:
A. NAD+
B. * c-AMP
C. NADP+
D. FMN
E. FAD
277.
Consider the synthesis of a biopolymer in which the addition of successive
monomers occurs by the same kind of reaction(s). The synthesis of the polymer is a
________ pathway.
A. Linear
B. Cyclic
C. * Spiral
D. Branched
E. A and B
278.
During succinyl CoA synthetesis generates
A. An energy deficient, unstable phosphoenzyme intermediate
B. An energy rich, unstable phosphoenzyme intermediate
C. * An energy rich, stable phopsphoenzyme intermediate
D. An energy deficient, stable phosphoenzyme intermediate
E. All of the above
279.
Each of the following catalyzed reactions of the citric acid cycle appears to be
metabolically irreversible except:
A. Citrate synthase
B. * Fumarase
C. Isocitrate dehydrogenase
D. Alpha ketoglutarate dehydrogenase complex
E. None of the above
280.
Each of the following leads to a biosynthetic pathway except:
A. Alpha ketoglutarate
B. Succinyl CoA
C. Oxaloacetate
D. Citrate
E. * None of the above
281.
Energy in biological systems is primarily
A. Electrical
B. * Chemical
C. Radiant
D. Mechanical
E. A and D
282.
Energy is carried from catabolic to anabolic reactions in the form of
A. ADP
B. * High-energy ATP bonds
C. Coenzymes
D. Inorganic phosphate
E. Oxygen
283.
Energy requiring metabolic pathways that yield complex molecules from simpler
precursors are:
A. Amphibolic.
B. * Anabolic.
C. Autotrophic.
D. Catabolic.
E. Heterotrophic.
284.
Fluoroacetate inhibits the reaction of citric acid cycle:
A. Isocitrate ?-Ketoglutarate
B. Fumarate -Malate
285.
286.
287.
288.
289.
290.
291.
292.
C. * Citrate -cis-aconitate
D. Succinate –fumarate
E. All of these
For one turn of Krebs cycle forms ATP (molecules):
A. 38 ATP
B. * 12 ATP
C. 15 ATP
D. 1 ATP
E. 15 ATP
Formation of succinyl-CoA from ?-Ketoglutarate is inhibited by
A. Fluoroacetate
B. * Arsenite
C. Fluoride
D. Iodoacetate
E. All of these
In citric acid cycle, NAD is reduced in
A. One reactions
B. Two reactions
C. * Three reactions
D. Four reactions
E. Five reactions
In eukaryotes the enzymes of the citric acid cycle are found in the _________.
A. cytosol
B. * mitochondria
C. nucleus
D. endoplasmic reticulum
E. both A and B
In eukaryotes the enzymes of the citric acid cycle are found in the _________.
A. cytosol
B. * mitochondria
C. nucleus
D. endoplasmic reticulum
E. all of these
Isocitrate dehydrogenase is allosterically inhibited by
A. Oxalosuccinate
B. ?-Ketoglutarate
C. * ATP
D. NADH
E. Both B and C
Malonate
A. Is a structural analogy of succinate
B. Binds to the substrate binding site of the succinate dehydrogenase complex but
does not react
C. Undergoes an oxidation reaction
D. * Both a and b
E. All of the above
Malonate is an inhibitor of
A. Malate dehydrogenase
B. ?-ketoglutarate dehydrogenase
C. * Succinate dehydrogenase
D. Isocitrate dehydrogenase
E. Both C and D
293.
Most of the metabolic pathways are either anabolic or catabolic. Which of the
following pathways is considered as “amphibolic” in nature?
A. Glycogenesis
B. Glycolytic pathway
C. Lipolysis
D. * TCA cycle
294.
NAD-dependent malate dehydrogenase
A. Catalyzes the oxidation of malate to regenerate oxaloacetate
B. Catalyzes the conversion of fumarase to malate
C. Catalyzes a reaction which results in the formation of an NADH molecule
D. All of the above
E. * a and c only
295.
One molecule of glucose gives ______molecules of CO2 in TCA cycle.
A. * 6
B. 3
C. 1
D. 2
E. 12
296.
Oxidative decarboxylation of pyruvate requires
A. NADP+
B. Cytichromes
C. pyridoxal phosphate
D. * COASH
E. All of the above
297.
Oxidative decarboxylation of pyruvate requires
A. NADP+
B. Cytochromes
C. pyridoxal phosphate
D. * CoASH
E. Pyridoxine
298.
Oxidative degradation of acetyl coenzyme A (CoA) in the citric acid cycle gives a
net yield of which of the following chemicals?
A. Flavin adenine dinucleotide (FADF)
B. Nicotinamide adenine dinucleotide (NADN)
C. Adenosine triphosphate (ATP)
D. Guanosine diphosphate (GDP)
E. * Carbon dioxide (CO2)
299.
Please match the following reaction Malate dehydrogenase to its respective
energy yielding products shown in answers A through E.
A. * NADH
B. QH2
C. GTP or ATP
D. ADP
E. NAD
300.
Please match the following reaction Succinate dehydrogenase complex to its
respective energy yielding products shown in answers A through E.
A. NADH
B. * QH2
C. GTP or ATP
D. ADP
E. NAD
301.
Please match the following reaction Succinyl CoA synthetase to its respective
energy yielding products shown in answers A through E.
A. NADH
B. QH2
C. * GTP or ATP
D. ADP
E. NAD
302.
Please match the following reaction Alpha ketoglutarate dehydrogenases complex
to its respective energy yielding products shown in answers A through E.
A. * NADH
B. QH2
C. GTP or ATP
D. ADP
E. NAD
303.
Please match the following reaction Isocitrate dehydrogenase to its respective
energy yielding products shown in answers A through E.
A. * NADH
B. QH2
C. GTP or ATP
D. ADP
E. NAD
304.
Product of a pathway controls the rate of its own synthesis by inhibiting an early
step. Such way of enzyme regulation is called:
A. * feedback inhibition;
B. feed-forward activation;
C. autoregulation;
D. none of the above.
E. feedback activation
305.
Product of a pathway controls the rate of its own synthesis by inhibiting an early
step. Such way of enzyme regulation is called:
A. * feedback inhibition;
B. feed-forward activation;
C. autoregulation;
D. none of the above.
E. feedback activation
306.
Prosthetic group of cytochrome is:
A. FAD
B. Ubiqinon
C. Biotin
D. * Iron porphyryn complex
E. Cooper contain porphyryn complex
307.
Pyruvate can be form from all substrates, except one:
A. Lactate
B. Glycerol
C. Glucose
D. * Fatty acids
E. Glycogen
308.
Pyruvate dehydrogenase complex and ?-ketoglutarate dehydrogenase complex
require the following for their oxidative decarboxylation:
A. COASH and Lipoic acid
B. NAD+ and FAD
C. COASH and TPP
D. * COASH, TPP,NAD+,FAD, Lipoate
E. COASH, TPP, FAD, Lipoate
309.
Substrates of the respiratory chain are all, except one:
A. Isocitrate
B. Malate
C. * Oxaloacetate
D. Succinate
E. E-кеtoglutarate
310.
Substrates of the respiratory chain are all, except one:
A. Isocitrate
B. Malate
C. * Oxaloacetate
D. Succinate
E. E-кеtoglutarate
311.
Substrates of the respiratory chain are all, except one:
A. Isocitrate
B. Malate
C. C-кеtoglutarate
D. Succinate
E. * Lactate
312.
The activity of pyruvate carboxylase is dependent upon the positive allosteric
effector
A. Succinate
B. AMP
C. Isocitrate
D. Citrate
E. * Acetyl CoA
313.
The carrier of the citric acid cycle is
A. Succinate
B. Fumarate
C. Malate
D. * Oxaloacetate
E. All of these
314.
The carrier of the citric acid cycle is
A. Succinate
B. Fumarate
C. Malate
D. * Oxaloacetate
E. All of the above
315.
The citric acid cycle is inhibited by which of the following?
A. * Fluoroacetate
B. Fluorouracil
C. Aerobic conditions
D. Arsenic
E. Malic acid
316.
The citric acid cycle is the _________________________________________.
A. * final common pathway for the catabolism of fuel molecules — carbohydrates,
fatty acids and amino acids;
B. the anabolic pathway in which macromolecules are synthesized from monomers;
C. the biochemical pathway in which glucose is oxidized to acetyl CoA;
D. the biochemical pathway in which glucose is synthesized from noncarbohydrate
components.
E. final common pathway for the catabolism of carbohydrates;
317.
The citric acid cycle oxidizes pyruvate and some of the pathway intermediates are
starting materials for many biosynthetic pathways. This means the citric acid cycle is a/an
______________.
A. amplifying pathway
B. strictly catabolic pathway
C. anaerobic pathway
D. * amphibolic pathway
E. both A and D
318.
The citric acid cycle oxidizes pyruvate and some of the pathway intermediates are
starting materials for many biosynthetic pathways. This means the citric acid cycle is a/an
______________.
A. amplifying pathway
B. strictly catabolic pathway
C. anaerobic pathway
D. * amphibolic pathway
319.
The cycle of tricarboxilic acids begins with the reaction of substrates:
A. Pyruvate and acetyl CoA
B. Citric acid and acetyl CoA
C. * Oxaloacetate and acetyl CoA
D. Succinate and isocitrate
E. Isocitrate and oxaloacetate
320.
The decarboxylation of pyruvate produces
A. NADH
B. Acetyl
C. CO2
D. ATP
E. * A, b, and c
321.
The degradation of which class of biochemicals does not significantly contribute
to the release of energy to cells?
A. * Nucleic acids
B. Proteins
C. Lipids
D. Carbohydrates
E. B and C
322.
The degradative Processess are categorized under the heading of
A. Anabolism
B. * Catabolism
C. Metabolism
D. All of these
E. None of the above
323.
The entry point into the citric acid cycle for isoleucine, valine, and the product of
odd-chain fatty acids is
A. Fumarate
B. Pyruvate
C. * Oxaloacetate
D. Citrate
E. Succinyl CoA
324.
The enzyme pyruvate translocase is located ______________.
A. in the cytosol
B. * in the inner mitochondrial membrane
C. in the mitochondrial matrix
D. in the endoplasmic reticulum
325.
The enzymes of the citric acid cycle are located in
A. * Mitochondrial matrix
B. Extramitochondrial soluble fraction of the cell
C. Nucleus
D. Endoplasmic reticulum
E. Mitochondrial membrane
326.
The enzymes of the Krebs cycle are located in the
A. * Cytoplasm
B. Inter-membrane space of mitochondria
C. Vesicles of the ER
D. Outer membrane of the mitochondria
E. Matrix of the mitochondria
327.
The example of generation of a high energy phosphate at the substrate level in the
citric acid cycle is the reaction:
A. Isocitrate >?-Ketoglutarate
B. Succinate > fumarate
C. Malate > oxaloacetate
D. * Succinyl CoA > Succinate
E. Both A and D
328.
The flow of material through a reaction pathway usually depends on
________________.
A. * Control at several steps in the pathway
B. Control of the first step of the pathway
C. Covalent modification of the enzyme that catalyzes the reaction
D. Feed-forward activation
E. Control of the second step of the pathway
329.
The flow of material through a reaction pathway usually depends on
________________.
A. * Control at several steps in the pathway
B. Control of the first step of the pathway
C. Covalent modification of the enzyme that catalyzes the reaction
D. Feed-forward activation
E. Control of the second step of the pathway
330.
The following co-enzyme is needed for the oxidative decarboxylation of
ketoacids:
A. NADP+
B. TPP
C. Folate coenzyme
D. Biotin coenzyme
E. None of these
331.
The following coenzyme is needed for the oxidative decarboxylation of ketoacids:
A. NADP+
B. * TPP
C. Folate coenzyme
D. Biotin coenzyme
E. Both B and C
332.
The function of protein kinase is:
A. synthesis of ATP from two ADP molecules;
B. catalysis of the oxidation-reduction reactions;
C. * phosphorylation of proteins (enzymes);
D. dephosphorylation of proteins (enzymes).
E. none of the above.
333.
The initial step of the citric acid cycle is
A. Conversion of pyruvate to acetyl-CoA
B. * Condensation of acetyl-CoA with oxaloacetate
C. Conversion of citrate to isocitrate
D. Formation of ??-ketoglutarate catalysed by isocitrate dehydrogenase
E. Both A and B
334.
The list of cofactors which are able in the process of fermentative reactions to
carry electrons and protons is below resulted, except of one cofactor which carries
chemical groups only. Choose it:
A. NAD
B. * Pyridoxal phosphate
C. FAD
D. Ubiqinon (coenzyme Q)
E. Hem coenzymes
335.
The number of molecules of ATP produced by the total oxidation of acetyl CoA
in TCA cycle is
A. 6
B. 8
C. 10
D. * 12
E. 15
336.
The oxidation of acetyl CoA in citric acid cycle to CO2 and water is the
_________ stage of catabolism and this is ___________ stage.
A. first, specific;
B. second, nonspecific;
C. third, specific;
D. * third, nonspecific.
E. second, specific.
337.
The process by which a cell is built up from the simple nutrients obtained from its
environment is called _____.
A. * Anabolism
B. Biosynthesis
C. Catabolism.
D. All of the above
E. More than one of the above, but not all
338.
The reaction Pyruvate + CO2 + ATP + H2O ( Oxaloacetate + ADP + Pi is the
example of ____________ reactions that ____________citric acid cycle intermediates.
A. anaplerotic; replenish;
B. catabolic; remove;
C. anabolic; remove;
D. * anaplerotic; remove.
E. all of the above
339.
The reaction of Kreb’s cycle which does not require cofactor of vitamin B group
is
A. * Citrate > isocitrate
B. ??-Ketoglutarate > succinate
C. Malate > oxaloacetate
D. Succinate > fumarate
E. Both A and D
340.
The reaction succinyl CoA to succinate requires
A. CDP
B.
C.
D.
E.
* ADP
GDP
NADP+
TPP
341.
The reaction succinyl COA to succinate requires
A. CDP
B. * ADP
C. GDP
D. NADP+
E. All of the above
342.
The second stage of aerobic oxidation of glucose in a cell is oxidative
decarboxilation of pyruvate. Name the main product of this proces.
A. * Acetyl CoA
B. Succinate
C. Pyruvate
D. Citrate
E. Oxaloacetate
343.
The second stage of aerobic oxidation of glucose in a cell is oxidative
decarboxilation of pyruvate. Name the main product of this proces.
A. Acetyl CoA
B. * Succinate
C. Pyruvate
D. Citrate
E. Oxaloacetate
344.
The step at which acetyl CoA enters the citric acid cycle is classified as a
___________ reaction.
A. * condensation
B. substrate-level phosphorylation
C. decarboxylation
D. dehydrogenation
E. oxidative phosphorylation
345.
The step at which ATP releases in the citric acid cycle is classified as a
___________ reaction.
A. condensation
B. * substrate-level phosphorylation
C. decarboxylation
D. dehydrogenation
E. oxidative phosphorylation
346.
The step at which CO2 releases in the citric acid cycle is classified as a
___________ reaction.
A. condensation
B. substrate-level phosphorylation
C. * decarboxylation
D. dehydrogenation
E. oxidative phosphorylation
347.
The substance which may be considered to play a catalytic role in citric acid cycle
is
A. * Oxaloacetate
B. Isocitrate
C. Malate
D. Fumarate
E. Succinyl CoA
348.
A.
B.
C.
D.
E.
349.
A.
B.
C.
D.
E.
350.
A.
B.
C.
D.
E.
The succinate dehydrogenase complex catalyzes
The formation of a single hydrogen bond in the oxidation of succinate to fumarate
* The formation of a double bond in the oxidation of succinate to fumarate
Both a and b
The formation of a macroergic bond
None of the above
The TCA cycle:
Is found in the cytosol
* Is controlled by calcium ion, the ADP/ATP ratio, and the NADH concentration
Is also called the Cori cycle
Consumes most of the CO2 produced by ribosomes
Produces most of the water made in humans
The temperature of human body supported due to all of processes, except one:
Katabolism of proteinsns, lipids, carbohydrates (specific stage)
Glycolysis
Katabolism (general stage)
TCA and oxidative phosphorylating
* Gluconeogenesis
The transfer of free energy from catabolic pathways to anabolic pathways is best
351.
called
A. Feedback regulation.
B. Bioenergetics.
C. Cooperativity.
D. * Energy coupling.
E. Entropy.
352.
There are ____ enzymes in the pyruvate dehydrogenase complex and ____
coenzymes: _______________________________________________.
A. 5; 5: TPP, lipoamide, HS-CoA, FAD+, NAD+
B. * 3; 5: TPP, lipoamide, HS-CoA, FAD+, NAD+
C. 3; 5: PLP, lipoamide, HS-CoA, FAD+, NADP+
D. 4; 5: PLP, lipoamide, HS-CoA, FAD+, NADP+
E. 5; 5: PLP, lipoamide, HS-CoA, FAD+, NADP+
353.
There are 4 main functions of Krebs cycle, except:
A. Oxidation of acetic acid into СО2 і Н2О
B. Donator of hydrogen atoms for respiratory chain
C. * Oxidation of lactate into pyruvate
D. Formation of ATP
E. Supplying substrates for heme synthesis
354.
There are 4 main functions of Krebs cycle, except:
A. Oxidation of acetic acid into СО2 і Н2О
B. * Donator of hydrogen atoms for respiratory chain
C. Oxidation of lactate into pyruvate
D. Formation of ATP
E. Supplying substrates for heme synthesis
355.
There are such three enzymes in pyruvate dehydrogenase complex:
A. Pyruvate carboxylase, lactate dehydrogenase, citrate synthase
B. * Pyruvate dehydrogenase, dihydrolipoyl acetyl transferase, dihydrolipoyl
dehydrogenase.
C. Ketoglutarate dehydrogenase, acetyltransferase, aconitase
D. NАDН2- dehydrogenase
E. Succinate dehydrogenase, aldehyde dehydrogenase.
356.
Tricarboxylic acid cycle to be continuous requires the regeneration of
A.
B.
C.
D.
E.
Pyruvic acid
* oxaloacetic acid
?-oxoglutaric acid
Malic acid
Fatty acids
357.
Tricarboxylic acid cycle to be continuous requires the regeneration of
A. Pyruvic acid
B. * oxaloacetic acid
C. ?-oxoglutaric acid
D. Malic acid
E. Fumaric acid
358.
Unlike NADH and NADPH, FAD and FADH
A. Donate one electron at a time
B. Donate one or two electrons at a time
C. Do not become positively charged
D. a and c
E. * b and c
359.
Where in a cell the tricarboxylic acid cycle takes place?
A. Within the inner compartment of the mitochondrion.
B. * In cytoplasm.
C. In nucleus.
D. In ribosomes.
E. All of these
360.
Which 5-carbon intermediate of the citric acid cycle is converted to a 4-carbon
molecule with the release of carbon dioxide?
A. fumarase
B. * а-ketoglutarate
C. succinate
D. isocitrate
E. citrate
361.
Which carbon atom(s) of pyruvate is(are) first converted to carbon dioxide by
pyruvate dehydrogenase complex?
A. * the carboxylate carbon (#1)
B. the carbonyl carbon (#2)
C. the methyl carbon (#3)
D. both carbons #1 and #3 in equal amounts
E. all of the above
362.
Which cofactor is not used by the pyruvate dehydrogenase complex?
A. lipoamide
B. thiamine pyrophosphate
C. FAD
D. * QH2
E. HS-CoA
363.
Which cofactor is not used by the pyruvate dehydrogenase complex?
A. lipoamide
B. thiamine pyrophosphate
C. FAD
D. * NAD
E. PLP
364.
Which enzyme catalyzes a metabolically irreversible reaction?
A. aconitase
B. * isocitrate dehydrogenase
C. fumarase
D. malate dehydrogenase
E. All of the above
365.
Which enzyme catalyzes a reaction that releases carbon dioxide?
A. a-ketoglutarate dehydrogenase complex
B. pyruvate dehydrogenase
C. * malate dehydrogenase
D. aconitase
E. both A and B
366.
Which enzyme catalyzes the citrate synthesis?
A. aldolase
B. * citrate synthase
C. citrate isomerase
D. aconitase
E. citrate dehydrogenase
367.
Which enzyme catalyzes the conversion of citrate to isocitrate?
A. aldolase
B. citrate synthase
C. citrate isomerase
D. * aconitase
E. epimerase
368.
Which enzyme does not catalyze a reaction that releases carbon dioxide?
A. A-ketoglutarate dehydrogenase complex
B. pyruvate dehydrogenase
C. * malate dehydrogenase
D. isocitrate dehydrogenases
E. both A and C
369.
Which enzyme does not catalyze a reaction that releases carbon dioxide?
A. a-ketoglutarate dehydrogenase complex
B. pyruvate dehydrogenase
C. * malate dehydrogenase
D. isocitrate dehydrogenases
E. All of these
370.
Which enzyme is the same in both pyruvate dehydrogenase complex and aketoglutarate complex?
A. * dihydrolipoamide dehydrogenase
B. aconitase
C. pyruvate decarboxylase
D. The two complexes have no components that are similar
E. Both A and B
371.
Which enzyme is the same in both pyruvate dehydrogenase complex and аketoglutarate complex?
A. * dihydrolipoamide dehydrogenase
B. aconitase
C. pyruvate decarboxylase
D. The two complexes have no components that are similar.
E. Dihydrolipoamide kinase
372.
Which intermediate of the citric acid cycle has a plane of symmetry?
A. * succinate
B. citrate
C. succinyl CoA
D. а-ketoglutarate
E. all of these
373.
Which is not a component of the Alfa ketoglutarate dehydrogenase complex?
A. dihydrolipoamide dehydrogenase
B. Alfa ketoglutarate dehydrogenase
C. * pyruvate dehydrogenase
D. dihydrolipoamide acetyltransferase
E. All of the above
374.
Which is not a component of the pyruvate dehydrogenase complex?
A. dihydrolipoamide dehydrogenase
B. * isocitrate dehydrogenase
C. pyruvate dehydrogenase
D. dihydrolipoamide acetyltransferase
E. both B and D
375.
Which is not a component of the pyruvate dehydrogenase complex?
A. dihydrolipoamide dehydrogenase
B. * Alfa ketoglutarate dehydrogenase
C. pyruvate dehydrogenase
D. dihydrolipoamide acetyltransferase
E. All of the above
376.
Which is not produced by the citric acid cycle?
A. NADH
B. * FMN
C. CO2
D. FADH2
E. none of the above
377.
Which is usually the slowest way to regulate a reaction in a metabolic pathway?
A. Allosteric modulation
B. Covalent modification
C. * Changing the enzyme concentration
D. All of the above are usually equally as fast
E. Competitive inhibitor
378.
Which is usually the slowest way to regulate a reaction in a metabolic pathway?
A. Allosteric modulation
B. Covalent modification
C. * Changing the enzyme concentration
D. All of the above are usually equally as fast
E. Competitive inhibitor
379.
Which of the following allosterically activates mammalian isocitrate
dehydrogenase?
A. ADP
B. NADH
C. Calcium
D. All of the above
E. * a and c only
380.
Which of the following are components of the succinate dehydrogenase complex?
A. FAD prosthetic group
B. Iron-sulfur clusters
C. Malonate
D. All of the above
E. * a and b only
381.
Which of the following describe(s) some aspect of metabolism?
A. Breakdown of macromolecules
B.
C.
D.
E.
Synthesis of macromolecules
Control of enzyme activity
* A and B only
A, B, and C
382.
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
383.
Which of the following is (are) true for anabolic pathways?
A. Catabolism involves the breakdown of energy-poor substrates into monomers.
Anabolism creates energy rich substrates from these monomers. Metabolism is
the sum of both of these processes
B. Catabolism is the breakdown of nutrients, anabolism is the generation of ATP.
Metabolism is the sum of both of these processes.
C. * Catabolism uses energy to breakdown nutrients into intermediates for
biosynthesis. Anabolism uses the intermediates for biosynthesis. Metabolism is
the sum of both of these processes.
D. Catabolism involves the multi-step breakdown of energy-rich nutrients into
smaller compounds; during this process energy is released. Anabolism uses the
energy released and the smaller compounds as intermediates for biosynthesis.
Metabolism is the sum of both of these processes
E. Anabolism involves the multi-step breakdown of energy-rich nutrients into
smaller compounds; during this process energy is released. Catabolism uses the
energy released and the smaller compounds as intermediates for biosynthesis.
Metabolism is the sum of both of these processes
F. They do not depend on enzymes.
G. They are highly regulated sequences of chemical reactions.
H. They consume energy to build up polymers from monomers.
I. They release energy as they degrade polymers to monomers.
J. Both B and C
384.
Which of the following is not a fate of a citric acid cycle intermediate?
A. Alpha ketoglutarate reversibly converting to glutamate
B. The biosynthesis of porphyrins from succinyl CoA's interaction with glycine
C. Oxabacetate as a carbohydrate precursor
D. * Acetyl CoA as fatty acids precursor
E. None of the above
385.
Which of the following is/are true statements about the succinate dehydrogenase
reactions?
A. * It is stereospecific
B. Only the cis-isomer of the product is formed
C. It is not stereospecific
D. Both b and c
E. Both a and b
386.
Which of the following metabolite integrates glucose and fatty acid metabolism?
A. * Acetyl CoA
B. Pyruvate
C. Citrate
D. Lactate
E. Fumarate
387.
Which of the following statements is false?
A.
B.
C.
D.
E.
Phosphofructokinase is the rate limiting enzyme in glycolysis
Phosphorylase activity is higher in Type II fibres than in Type I fibres
Endurance training increases the amount of TCA cycle enzymes in muscle
* Oxygen is consumed in the TCA cycle
The heart can oxidise lactate
388.
Which of the following statements is TRUE concerning catabolic pathways?
A. They build up complex molecules such as protein from simpler compounds.
B. They combine molecules into more complex and energy-rich molecules.
C. They are spontaneous and do not need enzyme catalysis.
D. They involve endergonic reactions that break complex molecules into simpler
ones.
E. * They are usually coupled with anabolic pathways to which they supply energy
in the form of ATP.
389.
Which of the following statements regarding T.C.A cycle is true?
A. It is an anaerobic process
B. It occurs in cytosol
C. It contains no intermediates for Gluconeogenesis
D. * It is amphibolic in nature
E. A and B
390.
Which of the following statements regarding T.C.A cycle is true?
A. It is an anaerobic process
B. It occurs in cytosol
C. It contains no intermediates for Gluconeogenesis
D. * It is amphibolic in nature
E. Both A and D
391.
Which of the following statements regarding the four "dehydrogenases" of the
TCA cycle is INCORRECT?
A. These are enzymes which remove electrons in the form of hydrogen from various
structures and transfer them to others
B. At least one catalyzes the "rate-limiting steps" of the TCA cycle
C. * GTP is generated from one of them via substrate level phosphorylation
D. NAD+ and FAD are the electron-accepting coenzymes for these enzymes
E. At least one catalyzes a reversible reactions
392.
Which statement does not explain why many biochemical processes are carried
out via multi-step pathways rather than by single-step reactions (or only a few steps)?
A. Multi-step pathways allow for more control points to regulate biochemical
processes.
B. * The end products of most pathways can usually be produced only by the
pathway reactions that nature has evolved.
C. Sharing of intermediates between pathways is facilitated this way.
D. There is greater control over the amounts of energy that are consumed or released
at any one time.
E. None of the above
393.
Which statement is false about most metabolic pathways?
A. * Most pathways are reversible under physiological conditions.
B. Pathways serve to increase the efficiency of energy transfers.
C. The rates of pathway reactions vary to respond to changing conditions.
D. The enzymes that catalyze reactions in metabolic pathways generally catalyze
only a single step.
E. Most pathways are irreversible under physiological conditions.
394.
Which statement is false about most metabolic pathways?
A. * Most pathways are reversible under physiological conditions.
B. Pathways serve to increase the efficiency of energy transfers.
C. The rates of pathway reactions vary to respond to changing conditions.
D. The enzymes that catalyze reactions in metabolic pathways generally catalyze
only a single step.
E. Most pathways are irreversible under physiological conditions.
395.
Which statement is not true about catabolic pathways?
A. They have a net release of energy.
B. * They have a net consumption of ATP.
C. They liberate smaller molecules from larger ones.
D. They include the citric acid cycle.
E. None of the above.
396.
Which statement is not true about catabolic pathways?
A. They have a net release of energy.
B. They have a net consumption of ATP.
C. They liberate smaller molecules from larger ones.
D. They include the citric acid cycl
E. A and C only
397.
Which step in the citric acid cycle is a rearrangement reaction?
A. succinyl CoA to succinate
B. fumarate to L-malate
C. * citrate to isocitrate
D. glucose 1,6-bisphosphate to fructose 1,6-bisphosphate
E. none of the above
398.
Which term most precisely describes the cellular process of breaking down large
molecules into smaller ones?
A. Dehydration
B. Catalysis
C. Anabolism
D. * Catabolism
E. Metabolism
399.
Which term most precisely describes the general process of breaking down large
molecules into smaller ones?
A. Anabolism
B. Catalysis
C. * Catabolism
D. Dehydration
E. Metabolism
400.
Why is ATP an important molecule in metabolism?
A. * It provides energy coupling between exergonic and endergonic reactions.
B. Its hydrolysis provides an input of free energy for exergonic reactions.
C. Its terminal phosphate group contains a strong covalent bond that when
hydrolyzed releases free energy.
D. A and B only
E. A, B and C
401.
Within the inner matrix of the mitochondrion are:
A. * The enzymes of the tricarboxylic acid cycle (Krebs’ cycle)
B. The components of the electron transport chain
C. Glycogen molecules
D. The enzymes of gluconeogenesis
E. The enzymes creatine kinase and carnitine acyl transferase 1
402.
Within the inner matrix of the mitochondrion are:
A. * The enzymes of the tricarboxylic acid cycle (Krebs’ cycle)
B.
C.
D.
E.
The components of the electron transport chain
Glycogen molecules
The enzymes of gluconeogenesis
The enzymes creatine kinase and carnitine acyl transferase 1
403.
The notion that ATP is generated by a proton gradient existing across a membrane
is called
A. Proton motion
B. Lactate reduction.
C. Cytochromic flow.
D. * Chemiosmotic theory.
E. Pyruvat decarboxilation
404.
A biological redox potential of reaction always involves:
A. * А loss of electrons
B. A gain of electrons
C. A reducing agent
D. An oxidizing agent
E. All of the above
405.
A reaction that is facilitated by FADH2 is most likely a(n)
A. Oxidation
B. * Reduction
C. Hydrolysis
D. Isomerization
E. None of the above.
406.
All of the following molecules are directly involved in the electron transport chain
except
A. Coenzyme Q
B. O2
C. * Pyruvate
D. FADH2
E. Cytochrome c
407.
All of the following situations are consistent with active transport EXCEPT
A. The conversion of ATP to ADP accompanies the movement of molecules.
B. The rate of oxygen consumption by the cell increases when molecules move
C. Molecules move in or out of a cell against the osmotic gradient
D. Cells accumulate diffusible molecules in greater quantity than was found outside
the cell.
E. * The rate of movement of molecules across the cell membrane increases i an
anaerobic environment.
408.
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
409.
Antibiotic antimycin blocks electron transport in the span from:
A. NADH to Fe-S proteins
B. Cytochrom c to aa3
C. * NADH to ubiquinone
D. Cytochrome b to c
E. NADH to cytochrome b
410.
Compare the pH of the mitochondrial matrix and inner membrane space.
A.
B.
C.
D.
The pH is lower in the matrix.
The pH in both regions is the same.
* The pH is lower in the inner membrane space.
The comparison of pH varies from moment to moment depending on energy
needs of the cell.
E. A and B only
411.
Cyanide is a poison that blocks the passage of electons along the electron
transport chain. Which of the following is a metabolic effect of this poison?
A. The pH of the intermembrane space becomes much lower than normal
B. Electrons are passed directly to oxygen, causing cells to explode
C. Alcohol would build up in the cells
D. NADH supplies would be exhasted, and ATP synthesis would cease.
E. * No proton gradient would be produced, and ATP synthesis would cease.
412.
Cyanide, oligomycin, and 2,4-dinitrophenol (DNP) are inhibitors of mitochondrial
aerobic phosphorylation. Which of the following statements correctly describes the mode
of action of the three inhibitors?
A. Cyanide and 2,4-dinitrophenol inhibit the respiratory chain, and oligomycin
inhibits the synthesis of ATP.
B. * Cyanide inhibits the respiratory chain, whereas oligomycin and 2,4dinitrophenol inhibit the synthesis of ATP.
C. Cyanide, oligomycin, and 2,4-dinitrophenol compete with O2 for cytochrome
oxidase (Complex IV).
D. Oligomycin and cyanide inhibit synthesis of ATP; 2,4-dinitrophenol inhibits the
respiratory chain.
E. Oligomycin inhibits the respiratory chain, whereas cyanide and 2,4-dinitrophenol
prevent the synthesis of ATP.
413.
Cytochromes a and a3 together are called :
A. Succinare dehydrogenase
B. Transaminase
C. Acorbatoxidase
D. * Cytochrome c oxidase
E. None of the above
414.
During aerobic respiration, electrons travel downhill from
A. Food-->Krebs Cycle-->ATP--> NAD+
B. * Food-->NADH-->electron transport chain-->oxygen
C. Glucose-->ATP-->oxygen
D. Glucose-->ATP-->electron transport chain-->NADH
E. Food-->glycolysis-->Krebs Cycle-->NADH-->ATP
415.
During ATP synthesis, the three identical b subunits of the F1 complex
A. * Have similar affinities for ADP and ATP
B. Have different affinities for ADP but not for ATP
C. Have different affinities for ATP but not for ADP
D. Have different affinities for ATP and for ADP
E. Do not bind ADP until a proton dissociates
416.
During cell respiration, most ATP is formed as a direct result of the net movement
of
A. Sodium ions diffusion across a membrane
B. Electrons flowing against a gradient
C. Electrons flowing througth a channel
D. * Protons flowing througth a channel
E. Protons flowing against a gradient
417.
During respiration, the substrate is
A.
B.
C.
D.
E.
418.
A.
B.
C.
D.
E.
Reduced
Hydrogenated
Carbonated
* Oxidised
A and D
FMN - prosthetic group of:
Lactatdehydrogenase
* NADH- dehydrogenase
Alcoholdehydrogenase
Creatincinase
Aminotranspherase
For very high force contractions lasting 1-2 seconds, the initial energy source is
419.
from:
A. Glycolysis
B. Creatine phosphorylation
C. Phosphocreatine stores
D. * ATP stores
E. None of the above
420.
How many ways of ATP formation are in the organism?
A. 1
B. * 2
C. 10
D. 3
E. 5
421.
In a fermentation metabolism, the organism produces ATP by
A. More than one of the above
B. * Generation of a proton motive force by transfer of electrons to oxygen.
C. Oxidizing NADH to form the proton motive force.
D. Substrate level phosphorylation.
E. None of the above
422.
In general, the higher the intensity of exercise, the greater the proportional
contribution of:
A. Aerobic energy production
B. * Anaerobic energy production
C. The TCA cycle (Krebs’ cycle) to the production of ATP
D. The electron transfer chain to the production of ATP
E. Fat oxidation
423.
In the chemiosmotic mechanism:
A. * ATP produciton is linked to the proton gradient established by the electron
transport chain.
B. The difference in pH between the intermembrane space and the cytosol drives the
formation of ATP.
C. The flow of H+ through ATP synthases from the matrix to the intermembrane
space drives the phosphorylation of ADP.
D. The energy released by the reduction and subsequent oxidation of components of
the electron transport chain is transferred as a phosphate to ADP.
E. The produciton of water in the matrix by the reduciton of oxygen leads to a net
flow of water out of a mitochondrion.
424.
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. * 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.
B. As a consequence of growing, organisms create more disorder in their
environment than the decrease in entropy associated with their growth
C. Living organisms are able to transform energy into entropy.
D. Living organisms do not obey the second law of thermodynamics, which states
that entropy must increase with time.
E. Living organisms do not follow the laws of thermodynamics.
425.
NADI-reagent include:
A. H2SO4 and ?-naphtol
B. * Para-phenilendiamine and B-naphtol
C. 2,4 - dinitrophenol and C-naphtol
D. Starch and para-phenilendiamine
E. None of the above
426.
Pyridine-linked dehydrogenases require as coenzymes:
A. FAD, FMN
B. * NAD, NADP
C. TPP, TDP
D. Coenzym A
E. THFA
427.
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. * Free-energy content.
E. Heat content.
428.
Several inhibitors block electron transport in the span between NADH and
ubiquinone, except:
A. Rotenone
B. Amytal
C. Piericidin
D. * Valinomicin
E. None of the above
429.
Substrates for respiratory chain are formed in:
A. Cytoplasm
B. Glycolysis
C. * Krebs cycle
D. Endoplasmic reticulum
E. Gluconeogenesis
430.
The _______ is a unit of chemical energy
A. Grams
B. Volts
C. * Joules/mol
D. Kilocalorie
E. More than one of the above
431.
The 1-st reaction of substrate-level phosphorylation takes place in the
mitochondria matrix and is located in:
A. * Respiratory chain
B. Decarboxilation of pyruvat
C. Gluconeogenesis
D. Krebs cycle
E. Oxidation of fatty acids
432.
The amount of energy required to bring all molecules to a reactive state prior to a
chemical reaction is called the reaction's _____________.
A. Van der Waal's energy
B. Go'
C. Free energy of formation
D. * Activation energy
E. More than one of the above is correct
433.
The antibiotic oligomycin serves as:
A. Activator of respiratiry chain
B. The ingibitor of Krebs cycle
C. * The inhibitor of oxidative phosphorylation
D. The ingibitor of substrate-level phosphorylation
E. None of the above
434.
The ATP produced during fermentation is generated by which of the following?
A. The electron transport chain
B. * Substrate-level phosphorilation
C. Krebs cycle
D. Chemiosmosis
E. Citric acid cycle
435.
The cytochromes are localized in the:
A. Cytosol
B. Nucleus
C. * Inner mitochondrial membrane
D. Ribosoms
E. Matrix of mitochondria
436.
The direct energy source that drives ATP synthesis during respiratory oxidative
phosphorylation is
A. Oxidation of glucose to CO2 and water
B. The thermodynamically favorable flow of electrons from NADH to the
mitochondrial electron transport carriers
C. The final transfer of electrons to oxygen
D. * The difference in H+ concentration on opposite sides of the inner mitochondrial
membrane
E. Thermodynamically favorable transfer of phosphate molecules (from glycolysis
and Krebs cycle intermediates) to ADP
437.
The electrons released by FADH2 during its oxidation to FAD by the electron
transport system finally end up as part of this molecule:
A. Glucose
B. * Water
C. Carbon dioxide
D. ATP
E. CO
438.
The immediate energy source that drives ATP synthesis by ATP synthase during
oxidative phosphorylation is :
A. The flow of electrons down the electron transport chain.
B. * The H+ concentration gradient across the inner mitochondrial membrane.
C. The oxidation of glucose and other organic compounds.
D. The transfer of phosphate to ADP.
E. The affinity of oxygen for electrons.
439.
the inner mitochondrial membrane.
A. The concentration of reduced coenzymes outside the mitochondrial
B. The energy difference between reduced carbon atoms and oxidized
C. * The concentration difference of hydrogen ions between the two sides of
D. The hydrolylsis of ATP to form ADP and Pi.
E. More than one of the above.
440.
The iron-sulfur proteins appear to function as electron carriers by undergoing
reversible :
A. Cu (I) to Cu (II) transitions
B. Na (I) to Na (II) transitions
C. Mg (I) to Mg (II) transitions
D. * Fe(II)-Fe(III) transitions.
E. None of the above
441.
The major reason that glycolysis is not as energy productive as respiration is that:
A. * NAD+ is regenerated by alcohol or lactate production, without the high-energy
electrons passing through the electron transport chain.
B. It is the pathway common to fermentation and respiration.
C. It does not take place in a specialized membrane bound organelle.
D. Pyruvate still contains much of the energy from glucose.
E. Substrate level phosphorylation is not as energy efficient as oxidative
phosphorylation.
442.
The metabolic function of fermentation is to:
A. Oxidize NADH to NAD+ so that glycolysis can continue in the absense of
oxygen.
B. Reduce NADH so that more ATP can be produced by the electron transport chain
C. Produce lactate during aerobic exercises
D. Oxidize pyruvate, thus releasing more energy.
E. * Make beer
443.
The metal ion that acts as an electron carrier in the cytochromes in the electron
transport chain is
A. Magnesium
B. Chromium
C. * Iron
D. Cobalt
E. Hydrogen
444.
The most common substrate of respiration is _________.
A. Amino acids
B. Fats
C. * Glucose
D. Sucrose
E. Vitamins
445.
The prototype of ionophores is the antibiotic:
A. Oligomicin
B. * Valinomycin
C. Antimicin
D. Piericidin
E. None of the above
446.
The terminal cytochrome of mitochondrial respiration include tightly bound:
A. Na
B. P
C. * Cu
D. CI
E. Mg
447.
There are four types of electron-transferring enzymes, except:
A. Pyridine-linked dehydrogenases
B.
C.
D.
E.
Flavin-linked dehydrogenases
Iron-sulfur proteins
* Retinol-isomerase
Cytochromes
448.
Ways of ATP formation in the organism:
A. Hydrolysis of simple proteins and separation of amino acid
B. Salting-out and denaturation of proteins
C. * Oxidative phosphorylation and substrate-level phosphorylation.
D. Decarboxilation of pyruvat and gluconeogenesis
E. All of above
449.
What is the change in free energy of a system at chemical equilibrium?
A. * No net change
B. Slightly increasing
C. Slightly decreasing
D. Greatly increasing
E. Greatly decreasing
450.
Where is ATP formed during oxidative phosphorylation ?
A. In the mitochondria
B. In the cytoplasm
C. In the respiratory chain
D. On the cytochromes
E. * On the ATP-synthase, which is located in the mitochondrial matrix and
penetrate inner membrane
451.
Which of the following class of vitamins are found in NAD, FAD, and FMN?
A. Water soluble
B. Coenzymes
C. * B vitamins
D. Antioxidants
E. More than one of the above.
452.
Which of the following coenzymes would have to be continually present in the
cell in order for the oxidative reactions of glycolysis to continue?
A. FADH2
B. * NADH
C. ATP
D. NAD+
E. All of the above
453.
Which of the following describe(s) some aspect of metabolism?
A. Breakdown of macromolecules
B. Synthesis of macromolecules
C. Control of enzyme activity
D. * A and B only
E. A, B, and C
454.
Which of the following forms of energy is least available to accomplish cellular
work?
A. Electrical energy
B. * Mechanical energy
C. Light energy
D. Thermal energy (heat)
E. Potential energy
455.
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
456.
Which of the following is not a significant biological oxidizing agent?
A. Fe3+
B. NAD+
C. FAD
D. Ubiquinone (a.k.a. CoQ)
E. * O2
457.
Which of the following produces ATP, reduced coenzymes as high energy
molecules and CO2 as its major chemical waste product.
A. Electron transport
B. Glycolysis
C. beta – oxidation or fatty acids
D. * Citric acid cycle
E. Oxidative phosphorylation
458.
Which of the following reaction is incorrectly paired with its location?
A. * ATP synthesis>inner membrane of the mitochondrion, matrix, and cytosol.
B. Fermentation>cell cytosol
C. Glycolysis>cell cytosol
D. Substrate-level phosphorylation>cytosol and matrix
E. Citric acid cycle>cristae of mitochondrion
459.
Which of the following statements is true about the role of O2 in electron
transport?
A. * As the final electron acceptor, O2 gets reduced and becomes a part of a water
molecule.
B. As the final electron donator, O2 gets oxidized and becomes a part of an ATP
molecule.
C. As the final electron acceptor, O2 gets reduced and becomes a part of an ATP
molecule.
D. As the final electron donator , O2 gets oxidized and becomes a part of a NADH
molecule.
E. None of the above.
460.
Which process of cell respiration is most closely associated with intracellular
membranes?
A. Fermentation
B. The Krebs cycle
C. Glycolysis
D. Substrate-level phosphorilation
E. * Oxidative phosphorilation
461.
Which term most precisely describes the cellular process of breaking down large
molecules into smaller ones?
A. Dehydration
B. Catalysis
C. Anabolism
D. * Catabolism
E. Metabolism
462.
Why is ATP an important molecule in metabolism?
A. * It provides energy coupling between exergonic and endergonic reactions.
B. Its hydrolysis provides an input of free energy for exergonic reactions.
C. Its terminal phosphate group contains a strong covalent bond that when
hydrolyzed releases free energy.
D. A and B only
E. A, B and C
Test questions for figures
1. Coenzyme S-adenosylmethionine, shown in figure 52, participates in many reactions of
biosynthesis as a donator of:
A. Phosphoryl group
B. Acetyl group
C. Hydroxyl group
D. * Methyl group
E. Carboxyl group
2. Compound shown in figure 53 is a metabolite coenzyme which can donate phosphoryl
group in biochemical reactions. This compound is:
A. NADH
B. FADH2
C. TPP
D. * ATP
E. HS-CoA
3. Compound shown in figure 54 is the coenzyme for oxido-reductases. This is:
A. * NADH
B. FADH2
C. TPP
D. ATP
E. HS-CoA
4. Compound shown in figure 55 is the coenzyme for oxido-reductases. This is:
A. NADH
B. * FADH2
C. TPP
D. ATP
E. HS-CoA
5. Compound shown in figure 56 is the coenzyme for pyruvate dehydrogenase and
transketolase. This is:
A. NADH
B. FADH2
C. * TPP
D. ATP
E. HS-CoA
6. Electrons flow through the ETC components shown in figure 76 spontaneously in the
direction of increasing redox potentials. What is the reduction potential of the component
replaced with digit 5?
A. -0.32
B. -0.82
C. * +0.82
D. 0.00
E. +0.32
7. Equation shown in the figure 68 represents:
A. * Theory of intermediate enzyme-substrate complex
B. Induced-fit theory of enzyme and substrate
C. Lock-and-key theory of enzyme and substrate
D. Koshland theory
E. Fisher theory
8. ETC consists of several complexes. What is the name of complex shown in figure 77?
A. * Complex I (NADH-ubiquinone oxidoreductase)
B. Complex II (succinate-ubiquinone oxidoreductase)
C. Complex III (ubiquinone-cytochrome c oxidoreductase)
D. Complex IV (cytochrome c oxidase)
E. Complex V (NADH-cytochrome c oxidoreductase)
9. ETC consists of several complexes. What is the name of complex shown in figure 78?
A. Complex I (NADH-ubiquinone oxidoreductase)
B. * Complex II (succinate-ubiquinone oxidoreductase)
C. Complex III (ubiquinone-cytochrome c oxidoreductase)
D. Complex IV (cytochrome c oxidase)
E. Complex V (NADH-cytochrome c oxidoreductase)
10. ETC consists of several complexes. What is the name of complex shown in figure 79?
A. Complex I (NADH-ubiquinone oxidoreductase)
B. Complex II (succinate-ubiquinone oxidoreductase)
C. * Complex III (ubiquinone-cytochrome c oxidoreductase)
D. Complex IV (cytochrome c oxidase)
E. Complex V (NADH-cytochrome c oxidoreductase)
11. ETC consists of several complexes. What is the name of complex shown in figure 80?
A. Complex I (NADH-ubiquinone oxidoreductase)
B. Complex II (succinate-ubiquinone oxidoreductase)
C. Complex III (ubiquinone-cytochrome c oxidoreductase)
D. * Complex IV (cytochrome c oxidase)
E. Complex V (NADH-cytochrome c oxidoreductase)
12. Formulate the phenomenon shown in figure 81.
A. The pumping of protons into the intermembrane space results in the electrons
flow through complexes of ETC.
B. * As electrons flow through complexes of ETC, protons are translocated from
matrix into the intermembrane space.
C. Electron transport through complexes of ETC is inhibited by ATP synthesis.
D. Electron transport and ATP synthesis are coupled by a OH- gradient across the
inner mitochondrial membrane.
E. The pumping of protons into the matrix results in the electrons flow through
complexes of ETC.
13. How many protons are pumped out of the matrix when two electrons flow through the
ETC complex shown in the figure 77?
A. 1
B. 2
C. 3
D. * 4
E. 5
14. How many protons are pumped out of the matrix when two electrons flow through the
ETC complex shown in the figure 78?
A. 1
B. 2
C. 3
D. 4
E. * 0
15. How many protons are pumped out of the matrix when two electrons flow through the
ETC complex shown in the figure 79?
A. 1
B. 2
C. 3
D. * 4
E. 0
16. How many protons are pumped out of the matrix when two electrons flow through the
ETC complex shown in the figure 80?
A. 1
B. * 2
C. 3
D. 4
E. 0
17. How many protons are pumped out of the matrix when two electrons flow through the
ETC shown in the figure 80?
A. * 10
B. 3
C. 4
D. 15
E. 0
18. In electron transport chain shown in figure 76 some components are missing. Which
carrier is replaced with digit 1?
A. * FMN
B. FAD
C. CoQ
D. Cytochrom c
E. Fe-S clusters
19. In electron transport chain shown in figure 76 some components are missing. Which
carrier is replaced with digit 3?
A. FMN
B. FAD
C. * CoQ
D. Cytochrom c
E. Fe-S clusters
20. In electron transport chain shown in figure 76 some components are missing. Which
carrier is replaced with digit 4?
A. FMN
B. FAD
C. CoQ
D. * Cytochrom c
E. Fe-S clusters
21. In electron transport chain shown in figure 76 some components are missing. Which
component is replaced with digit 5?
A. FMN
B. FAD
C. * O2
D. Cytochrom c
E. Fe-S clusters
22. In electron transport chain shown in figure 79 some components are missing. Which
carrier is replaced with digit 2?
A. FMN
B. * FAD
C. CoQ
D. Cytochrom c
E. Fe-S clusters
23. In figure 61 the example of reaction is shown.
A. Oxidation-reduction
B. Hydrolysis
C. * Group transfer
D. Synthesis
E. Isomerization
24. In figure 62 the example of reaction is shown.
A. Oxidation-reduction
B. * Hydrolysis
C. Group transfer
D. Synthesis
E. Isomerization
25. In figure 63 the example of reaction is shown.
A. Oxidation-reduction
B. Hydrolysis
C. Group transfer
D. * Lysis of substrate
E. Isomerization
26. In figure 64 the example of reaction is shown.
A. Oxidation-reduction
B. Hydrolysis
C. Group transfer
D. Lysis of substrate
E. * Isomerization
27. In figure 65 the example of reaction is shown.
A. Oxidation-reduction
B. Hydrolysis
C. Group transfer
D. * Ligation
E. Isomerization
28. In the figure 71 activator binds noncovalently to specific site and regulate enzyme
activity via conformational changes. This activator can be also called:
A. * Allosteric modulator
B. Covalent modulator
C. Proteolytic factor
D. Negative modulator
E. Covalent factor
29. In the figure 72 the reaction of covalent modification of enzyme is shown. Such
modification is called:
A. Acetylation
B. Methylation
C. Sulfation
D. Carboxylation
E. * Phosphorylation
30. In the figure 73 the scheme of enzyme is shown.
A. Allosteric regulation
B. * Covalent modification
C. Proteolytic cleavage
D. Negative feedback regulation
E. Positive feedback regulation
31. In the figure 74 the scheme of enzyme regulation is presented. Such mechanism is called:
A. * Feedback inhibition
B. Feedback activation
C. Proteolytic activation
D. Positive feedback
E. Allosteric regulation
32. In the figure 78 the reaction of enzyme is shown.
A. Allosteric regulation
B. Covalent modification
C. * Proteolytic cleavage
D. Negative feedback regulation
E. Positive feedback regulation
33. In which reactions in biological pathway shown in figure 92 NADH are formed?
A. 1, 3, 6
B. 4, 5, 8
C. 2, 4, 8
D. 3, 5, 7
E. * 2, 3, 7
34. Membrane of which organelle is shown in figure 81?
A. Nucleus
B. * Mitochondria
C. Endoplasmic reticulum
D. Cell membrane
E. Lysosome
35. NAD in the reaction shown in figure 60 plays the role of:
A. Donor of protons
B. Donor of electrons
C. Acceptor of proton
D. Acceptor of electrons
E. * Acceptor of protons and electrons
36. Name the enzyme catalyzing the reaction shown in figure 91.
A. Protein kinase
B. * Pyruvate dehydrogenase
C. Pyruvate carboxylase
D. Pyruvate corboxykinase
E. Acetyl CoA dehydrogenase
37. Name the enzyme which is replaced with question-mark in figure 89.
A. Dehydrogenase
B. * Protein kinase
C. Adenylatcyclase
D. ATP-ase
E. Aldolase
38. Name the product of reaction depicted in figure 91.
A. Citrate
B. * Acetyl CoA
C. Oxaloacetate
D. Phosphoenol pyruvate
E. Isocitrate
39. The complex enzyme is shown in the figure 49. The nonprotein part of this enzyme is
called:
A. Coenzyme
B. Cofactor
C. * Prosthetic group
D. Apoenzyme
E. Holoenzyme
40. The curve reflecting the enzyme activity vs pH is shown in figure 58. Which enzyme
most probably is it?
A. Amilase
B. Chemotrypsin
C. Trypsin
D. * Pepsin
E. Lipase
41. The curve shown in figure 66 is typical for description of:
A. The effect of temperature on enzyme activity
B. The effect of pH on enzyme activity
C. * The effect of substrate concentration on the rate of reaction
D. The effect of enzyme concentration on the rate of reaction
E. The effect of pH on the rate of reaction
42. The curve shown in figure 67 is typical for description of:
A. The effect of temperature on enzyme activity
B. The effect of pH on enzyme activity
C. The effect of substrate concentration on the rate of reaction
D. * The effect of enzyme concentration on the rate of reaction
E. The effect of pH on the rate of reaction
43. The enzyme catalyzing the oxidation-reduction reaction shown in figure 60 belong to the
following subclass:
A. Oxidases
B. Peroxidases
C. * Dehydrogenases
D. Peptidases
E. Esterases
44. The enzyme catalyzing the reaction of hydrolysis shown in figure 62 belong to the
following subclass:
A. * Phosphatases
B. Peroxidases
C. Dehydrogenases
D. Peptidases
E. Esterases
45. The enzyme shown in figure 49 can be characterized as:
A. Simple enzyme
B. * Metalloenzyme
C. Apoenzyme
D. Isoenzyme
E. Multifunctional enzyme
46. The following enzymes cannot function without the coenzyme shown in figure 54:
A. Peroxidases
B. Esterases
C. Glucosidases
D. * Dehydrogenases
E. Peptidases
47. The following enzymes cannot function without the coenzyme shown in figure 55:
A. Peroxidases
B. Esterases
C. Glucosidases
D. * Dehydrogenases
E. Peptidases
48. The following enzymes cannot function without the coenzyme shown in figure 56:
A. Peroxidase
B. Catalase
C. Glucosidase
D. * Pyruvate dehydrogenase
E. Peptidase
49. The formula shown in figure 68 is called:
A. * Michaelis-Menten equation
B. Krebs equation
C. Horbachevsky equation
D. Mitchell equation
E. Kori equation
50. The fragment of the enzyme structure is shown in the figure 49. Such enzyme can be
characterized as:
A. Simple enzyme
B. * Complex enzyme
C. Coenzyme
D. Isoenzyme
E. Multifunctional enzyme
51. The mechanism of active site-substrate interaction shown in figure 50 is called:
A. Induced-fit model
B. Chemiosmotic model
C. Allosteric model
D. * Lock and key model
E. Covalent binding model
52. The mechanism of active site-substrate interaction shown on figure 51 is called:
A. * Induced-fit model
B. Chemiosmotic model
C. Allosteric model
D. Lock and key model
E. Covalent binding model
53. The mechanism of enzyme activation presented in figure 75 is called:
A. Feedback activation
B. Positive activation
C. * Proteolytic activation
D. Covalent activation
E. Allosteric activation
54. The precursor for coenzyme FADH2 shown in figure 7 is:
A. Thiamin
B. * Riboflavin
C. Lipoic acid
D. Pyridoxine
E. Nicotinamide
55. The precursor for coenzyme NAD shown in figure 54 is:
A. Thiamin
B. Riboflavin
C. Lipoic acid
D. Pyridoxine
E. * Nicotinamide
56. The precursor for coenzyme NAD shown in figure 9 is:
A. Thiamin
B. Riboflavin
C. Lipoic acid
D. Pyridoxine
E. * Nicotinamide
57. The process of electron transferring via the factors shown in figure 76 is called:
A. Oxidative respiration
B. Oxidative phosphorylation
C. Substrate-level phosphorylation
D. * Tissue respiration
E. Substrate-level oxidation
58. The scheme of stages of catabolism is shown in figure 90. What compound is replaced
with the digit 1?
A. * Glucose
B. Pyruvate
C. Acetyl CoA
D. Citrate
E. NADH
59. The scheme of stages of catabolism is shown in figure 90. What compound is replaced
with the digit 2?
A. Glucose
B. Pyruvate
C. * Acetyl CoA
D. Citrate
E. NADH
60. The sequence of components shown in figure 76 is called:
A. * Electron transport chain
B. Proton transport chain
C. NADH transport chain
D. NADH-O2 oxido-reductase
E. Proton ATP-ase
61. The typical curve reflecting the enzyme activity vs pH is shown in figure 57. Which
value of pH the question-mark corresponds to?
A. 5
B. 6
C. * 7
D. 8
E. 9
62. The typical curve reflecting the enzyme activity vs temperature is shown in figure 59.
Which value of temperature does the question-mark correspond to?
A. 27
B. 31
C. * 37
D. 42
E. 47
63. What biochemical pathway is shown in figure 92?
A. Glycolysis
B. Gluconeogenesis
C. Pentose phosphate pathway
D. * Citric acid cycle
E. Glycogenolysis
64. What compound is replaced with question-mark in figure 83?
A. ATP
B. * H3PO4
C. AMP
D. Pyruvate
E. Lactate
65. What enzyme catalyzes the reaction #1 in biological pathway depicted in figure 92?
A. Citrate synthase
B. * Aconitase
C. Isocitrate dehydrogenase
D. Alpha-ketoglutarate dehydrigenase
E. Succinyl CoA synthase
66. What enzyme catalyzes the reaction #4 in biological pathway depicted in figure 92?
A. Citrate synthase
B. Aconitase
C. Isocitrate dehydrogenase
D. Alpha-ketoglutarate dehydrigenase
E. * Succinyl CoA synthase
67. What enzyme catalyzes the reaction #5 in biological pathway depicted in figure 92?
A. Succinyl CoA synthase
B. * Succinate dehydrogenase
C. Fumarase
D. Malate dehydrogenase
E. Citrate synthase
68. What enzyme catalyzes the reaction #6 in biological pathway depicted in figure 92?
A. Succinyl CoA synthase
B. Succinate dehydrogenase
C. * Fumarase
D. Malate dehydrogenase
E. Citrate synthase
69. What enzyme catalyzes the reaction #7 in biological pathway depicted in figure 92?
A. Succinyl CoA synthase
B. Succinate dehydrogenase
C. Fumarase
D. * Malate dehydrogenase
E. Citrate synthase
70. What enzyme catalyzes the reaction 8 in biological pathway depicted in figure 92?
A. Succinyl CoA synthase
B. Succinate dehydrogenase
C. Fumarase
D. Malate dehydrogenase
E. * Citrate synthase
71. What enzyme catalyzes the reaction № 3 in biological pathway depicted in figure 92?
A. Citrate synthase
B. Aconitase
C. Isocitrate dehydrogenase
D. * Alpha-ketoglutarate dehydrogenase
E. Succinyl CoA synthase
72. What principle of enzyme regulation is shown in figure 87?
A. * Feedback inhibition
B. Feed-forward activation
C. Feed-forward inhibition
D. Feedback activation
E. None of the above
73. What principle of enzyme regulation is shown in figure 78?
A. Feedback inhibition
B. * Proteolytic activation
C. Feed-forward inhibition
D. Feedback activation
E. None of the above
74. What product is shown in figure 82?
A. * acetil Co A
B. H3PO4
C. AMP
D. Pyruvate
E. Lactate
75. What reaction is shown in figure 91?
A. Reduction of pyruvate
B. Oxidation of acetyl CoA
C. Entering of acetyl CoA into tricarboxylic acid cycle
D. * Oxidative decarboxylation of pyruvate
E. Oxidative reduction of pyruvate
76. What theory describes the scheme shown in figure 81?
A. Key-and-lock theory
B. Fit-induced theory
C. * Chemiosmotic theory
D. Enzyme-substrate complex theory
E. Koshland theory
77. What theory of active site-substrate interaction is presented in the figure 50?
A. * Fischer theory
B. Coshland theory
C. Horbachevky theory
D. Mitchell theory
E. Krebs theory
78. What theory of active site-substrate interaction is presented on the figure 51?
A. Fischer theory
B. * Coshland theory
C. Horbachevky theory
D. Mitchell theory
E. Krebs theory
79. What type of enzyme regulation is shown in figure 71?
A. Covalent modification
B. Uncompetitive
C. Competitive
D. * Allosteric
E. Proteolytic
80. What type of inhibition is shown in figure 69?
A. Noncompetitive
B. Uncompetitive
C. * Competitive
D. Allosteric
E. Proteolytic
81. What type of inhibition is shown in figure 70?
A. * Noncompetitive
B. Uncompetitive
C. Competitive
D. Allosteric
E. Proteolytic
82. What type of metabolic pathway is depicted in the figures 84?
A. * Linear
B. Cyclic
C. Spiral
D. Dichotomic
E. None of the above
83. What type of metabolic pathway is depicted in the figures 85?
A. Linear
B. * Cyclic
C. Spiral
D. Dichotomic
E. None of the above
84. What type of metabolic pathway is depicted in the figures 86?
A. Linear
B. Cyclic
C. * Spiral
D. Dichotomic
E. None of the above
85. Where does reaction depicted in figure 91 take place?
A. In cytoplasm
B. In nucleus
C. In endoplasmic reticulum
D. * In matrix of mitochondria
E. In lysosomes
86. Which class does the enzyme catalyzing the reaction shown in figure 61 belong to?
A. Oxido-reductases
B. * Transferases
C. Hydrolases
D. Lyases
E. Ligases
87. Which class does the enzyme catalyzing the reaction shown in figure 62 belong to?
A. Oxido-reductases
B. Transferases
C. * Hydrolases
D. Lyases
E. Ligases
88. Which class does the enzyme catalyzing the reaction shown in figure 68 belong to?
A. * Oxido-reductases
B. Transferases
C. Hydrolases
D. Lyases
E. Ligases
89. Which class does the enzyme catalyzing the reaction shown in figure 64 belong to?
A. Oxido-reductases
B. Transferases
C. Hydrolases
D. Lyases
E. * Isomerases
90. Which class does the enzyme catalyzing the reaction shown in figure 65 belong to?
A. Oxido-reductases
B. Transferases
C. Hydrolases
D. Lyases
E. * Ligases
91. Which class does the enzyme catalyzing the reaction shown in figure 60 belong to?
A. * Oxido-reductases
B. Transferases
C. Hydrolases
D. Lyases
E. Ligases