1. DNA differs from RNA in the following features
A DNA is resistant to base catalyzed hydrolysis; RNA is hydrolyzed by OH-.
B DNA residues are linked by 3'-->5' phosphodiester bonds; RNA is 2'-->5'
C DNA has deoxyribose residues; RNA has ribose residues.
D DNA contains the A, C, G and T bases; RNA contains A, C, G, and U.
E All but the second choice are correct differences. 2. Because DNA is a highly charged polyanion, its stability to heat denaturation
A does not depend on hydrophobic interactions.
B increases with increasing [salt].
C decreases with increasing [salt].
D is independent of G + C content.
E increases with increasing pH. 3. The total contour length of DNA in a human cell is about
A 1 mm.
B 1 mm.
C 10 cm.
D 1 meter.
E 12 furlongs. 4. Polyacrylamide and agarose gel electrophoresis separate nucleic acids based
primarily on their
B ratio of mass/charge.
C (G+C)/(A+T) content.
D organismal origin.
E content of 15N (buoyant density). 5. The number of supercoils in a covalently-closed, circular DNA can only be
A at least one of the phosphodiester chains is cleaved.
B both of the phosphodiester chains are cleaved.
C histones are bound to the DNA.
D the salt concentration is increased >1.0 M.
E chemical reagents react with the backbone phosphates. 6. Thymidine
A is equal to the adenosine concentration in double-stranded DNA.
B is replaced by Uracil in RNA.
C normally forms 2 hydrogen bonds with adenosine.
D can participate in hydrophobic interactions due to its methyl group.
E All of the above are correct. 7. The major and minor grooves of B-form DNA correspond to what features of
A minor and major grooves
B deep and shallow grooves
C deoxyribose backbones
D phosphoribose backbones
E Choices a) and d) are both correct. 8. The glycosidic bonds in DNA and RNA
A can be hydrolyzed by OH-.
B are free to rotate over about 180°.
C are restricted to one of four possible orientations.
D connect the sugar to the base.
E stabilize Watson-Crick H-bonds. 9. In solution, the grooves of nucleic acid helices
A are filled with H2O and counterions (M+ & M2+).
B expose the H-bonding groups of the bases.
C expose the hydrophobic surfaces of the bases.
D are about equal in width.
E Choices a) and b) are both correct. 10. If your genomic DNA could be typed for a specific genetic defect
A "I would not want to be tested, ever."
B "I would want to be tested now."
C "I might want to be tested later."
D "I need much more information before deciding."
E All four decisions are now being made by reasonable people. 11. The a-amino acids have a carboxyl group with a pK around ___ , and an
amino group with a pK near ___.
A 1, and 12.1
B 6.5, and 8.0.
C 3, and 10.5.
D 9.0, and 2.5.
E 2.2 and 9.5. 12. Which pair of amino acids absorbs the most UV light at 280 nm?
A Thr & His.
B Trp & Tyr.
C Cys & Asp.
D Phe & Pro.
E None of the above. 13. Which of the following is not a sensible grouping of amino acids based on
their polarity properties?
A Ala, Leu, and Val.
B Arg, His, and Lys.
C Phe, Trp, and Tyr.
D Asp, Ile, and Pro.
E Asn, Ser, and Thr. 14. The isoelectric point of an amino acid is defined as
A the pH where the molecule carries no net electric charge.
B the pH where the carboxyl group is uncharged.
C the pH where the amino group is uncharged.
D the pH of maximum electrolytic mobility.
E -log10(pKi + pKj) 15. When the amino acid alanine (the R-group is: -CH3) is added to a solution
with a pH of 7.3, alanine becomes:
A a cation.
C a zwitterion.
D an isotope.
E an anion. 16. Aspartic acid is similar to glutamic acid in the same way that
A His is similar to Pro.
B Ser is similar to Cys.
C Gln is similar to Asn.
D Asn is similar to Gln.
E Gly is similar to Val. 17. Alanine is similar to serine in the same way that
A Val is similar to Thr.
B Phe is similar to Tyr.
C Phe is similar to Trp.
D Ser is similar to Thr.
E Trp is similar to Pro. 18. Glycine is similar to valine in the same way that
A Ala is similar to Leu.
B Thr is similar to Met.
C Ala is similar to Ile.
D Arg is similar to Lys.
E None of the above are valid similarities. 19. A significant difference between His and Pro is that
A the His side chain is aromatic, the Pro side chain is aliphatic.
B His is an a-amino acid; Pro is an imino acid.
C the His side chain has a six-membered ring; Pro has a five-membered ring.
D the His side chain has a pK around pH = 7; the Pro side chain does not.
E All but the third choice are significant differences. 20. A significant difference between Phe and Tyr is that
A the Phe side chain is aromatic, the Tyr side chain is aliphatic.
B Tyr is an a-amino acid; Phe is an imino acid.
C the Tyr side chain has an -OH group; the Phe side chain does not.
D the Tyr side chain has a pK around pH = 7; the Phe side chain does not.
E All but the third choice are significant differences. 21. The peptide bond in proteins is
A planar, but rotates to three preferred dihedral angles.
B nonpolar, but rotates to three preferred dihedral angles.
C nonpolar, and fixed in a trans conformation.
D planar, and usually found in a trans conformation.
E not cleavable by hydrolysis. 22. The peptide, Val-Lys-Glu-Met-Ser-Trp-Arg-Ala, was digested with cyanogen
bromide (CNBr) to produce
A Val-Lys + Glu-Met-Ser + Trp-Arg-Ala.
B Val-Lys-Glu-Met-Ser-Trp + Arg-Ala.
C Val-Lys-Glu-Met + Ser-Trp-Arg-Ala.
D Val-Lys-Glu + Met-Ser-Trp-Arg-Ala.
E Val-Lys-Glu-Met-Ser + Trp-Arg-Ala. 23. The same peptide, Val-Lys-Glu-Met-Ser-Trp-Arg-Ala, was digested with
chymotrypsin to produce:
A Val-Lys + Glu-Met-Ser + Trp-Arg-Ala.
B Val-Lys-Glu-Met-Ser-Trp + Arg-Ala.
C Val-Lys-Glu-Met-Ser + Trp-Arg-Ala.
D Val-Lys-Glu + Met-Ser-Trp-Arg-Ala.
E Val-Lys-Glu-Met + Ser-Trp-Arg-Ala. 24. In b-pleated sheet structures
A neighboring chains lie in a flat plane.
B neighboring residues are hydrogen bonded.
C neighboring chains are connected by a-helices.
D neighboring residues have F & Y angles of about 90°.
E neighboring chains are hydrogen bonded. 25. If the F and Y angles of each peptide unit in a protein are known, the
following will also be determined:
A complete secondary structure.
B complete tertiary structure.
C complete quaternary structure.
D thermodynamic stability.
E Both the first and the second choices are correct. 26. Which of the following is an example of tertiary structure in a protein?
B a multimeric protein.
C an a-helix.
D a b-pleated sheet.
E a globular domain. 27. The portion of proteins having the highest mobility are
C peptide bonds.
D surface side chains.
E aliphatic groups. 28. Which of the following is most correct:
A Charged amino acids are never buried in the interior of a protein.
B Charged amino acids are seldom buried in the interior of a protein.
C All hydrophobic amino acids are buried when a protein folds.
D Tyrosine is only found in the interior of proteins.
E Glycine is rarely found in proteins because it is too destabilizing. 29. Disulfide bonds most often stabilize the native structure of:
A extracellular proteins.
B dimeric proteins.
C hydrophobic proteins.
D intracellular proteins.
E multisubunit proteins. 30. Buried hydrophobic sidechains in a globular protein fit into a "hole" formed
the sidechains of
A 1-3 other amino acids.
B precisely six other amino acids.
C 5-7 other amino acids.
D 9-12 other amino acids.
E 13-15 other amino acids. 31. Attractive van der Waals forces occur
A between apolar molecules in the liquid state.
B between any pair of nearby atoms.
C between polar molecules in the solid state.
D only if other forces are less favorable.
E only in the gas phase. 32. The strong conclusion from Anfinsen's work on RNaseA was that:
A 100% enzyme activity corresponds to the native conformation.
B disulfide bonds (S-S) in proteins can be reduced in vitro
C Cys-SH groups are not found in vivo
D the native conformation of a protein is adopted spontaneously.
E irreversible denaturation of proteins violates the "Thermodynamic
Hypothesis". 33. If Anfinsen had not determined the location of the S-S bonds in renatured
RNaseA, his result of >90% recovery of enzyme activity would
A have proven his hypothesis.
B not have been believed.
C not have been possible.
D have been hard to believe.
E have gone unnoticed. 34. The statement (from Campbell, p.127) that "the amino acid sequence of a
protein contains all of the information required for the complete three
A cannot be falsified by experiment; hence it is trivial.
B is strongly supported by many denaturation-renaturation experiments.
C is called an "hypothesis" since its validity is sort of dicey.
D is called a "model" because it can be diagrammed in textbooks.
E has essentially been proven by recent theoretical work. 35. 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. 36. The relationship between an enzyme and a reactant molecule can best be
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. 37. When [S] = Km, the velocity of an enzyme catalyzed reaction is about:
E 0.9*Vmax. 38. 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. 39. 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. 40. The transition state of a catalyzed reaction 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. 41. The substrate Km in an enzyme-catalyzed reaction
A is usually less than Kd, the dissociation constant.
B is never less than Kd.
C cannot be equal to Kd.
D is estimated from the Y-intercept of a Lineweaver-Burk plot.
E cannot be derived from simple rate equations. 42. When [S] = 0.1*Km, the velocity of an enzyme catalyzed reaction is about:
E 0.9*Vmax. 43. When [S] = 10*Km the velocity of an enzyme catalyzed reaction is about:
E 0.9*Vmax. 44. 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. 45. 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. 46. Which of the following common drugs is not a specific enzyme inhibitor?
E Viagra. 47. 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. 48. Which of the following statements is NOT a characteristic of catabolic
A. They serve to generate energy.
B. They often produce NADH or FADH2.
C. They are divergent processes in which a few precursors form a wide variety of
D. They often involve hydrolysis of macromolecules.
E. Glycolysis is an example of a catabolic pathway. 49. A kinase is an enzyme that:
A. adds water to a double bond.
B. uses FADH2 to change the oxidation state of the substrate.
C. uses ATP to add a phosphate group to the substrate.
D. removes phosphate groups off of substrates 50. ATP
A. Is primarily produced in catabolism and used in biosynthesis
B. Has a high energy of hydrolysis partly because of electrostatic repulsion
C. Is rarely an allosteric effector
D. Is the highest energy compound in cells 51. Choose the correct path taken by a pair of electrons as it travels down
the electron transport chain:
A NADH → complex I → complex II → Co Q → complexIII → Cyt C → complex
B FADH2 →complex I →Co Q → complex III → CytC → complex IV → O2
C NADH →complex II →Cyt C → complex III → CoQ → complex IV → O2
D NADH →complex I → Co Q → complex III → CytC → complex IV → O2 52. In the binding-change mechanism for ATP synthase,
A every proton that is translocated causes the formation of 1ATP
B ADP and Pi bind to the a-b protomer in the L conformation.
C ATP binds to the a-b protomer in the O conformation
D All three a-b protomers cycle through the same conformation at the same time 53. Which of the electron transport complexes are responsible for translocating
protons into the intermembrane space?
A Complex I, II, III, and IV.
B Complex I, III, and IV.
C Complex II and cytochrome c
D Complex I, III, IV and V
E Complex I and IV. 54. Which of the following is not correct concerning the uncoupling of electron
transport from oxidative phosphorylation:
A uncoupling slows all aerobic metabolic activities.
B uncoupling slows the citric acid cycle
C stops electron transport
D stops ATP synthesis. 55. Which of the following is not a redox center in the electron transport chain?
B Fe-S clusters
C Co Q
56. The electron transport chain
A Has components with mostly more positive electrode potentials going from NADH
B Has both 2 and 1 electron carriers
C Is a strictly linear, unbranched pathway (remember succinate dehydrogenase) 57. Coupling between electron transport and ATP synthesis
A Provides the control by which oxidation rates are governed by ATP utilization
B Is eliminated by uncouplers which inhibit the ATP synthase (Is eliminated, but
uncouplers don’t inhibit ATP synthase)
C Is always tight in animal mitochondria under physiological conditions (remember
D Is eliminated by lipid-soluble weak acids 58. Mitochondrial electron transport
A Is accomplished by both electron and hydride movements
B Proceeds in the absence of ATP synthesis
C Is accompanied by movements of protons across the membrane
D Can start with a variety of substrates, such as lactate, formate, glycerol-3P,
59.Uncoupling of mitochondrial oxidative phosphorylation:
A halts all mitochondrial metabolism.
B slows down the citric acid cycle.
C allows continued mitochondrial ATP formation, but halts O2 consumption.
D halts mitochondrial ATP formation, but allows continued O2 consumption.
E none of the above. 60. Which of the following statements about the chemiosmotic theory is correct?
A Electron transfer in mitochondria is accompanied by a release of protons on one
side of the inner mitochondrial membrane.
B The effect of uncoupling reagents is a consequence of their ability to carry electrons
C Although energy transductions in mitochondria and in chloroplasts are superficially
similar, they have fundamentally different mechanisms.
D The membrane ATPsynthase, which plays an important role in other hypotheses for
energy coupling, has no significant role in the chemiosmotic theory.
E All of the above statements are correct. 61. The rate of flow of electrons through the electron-transport chain is
A the ATP:ADP ratio.
B the concentration of acetyl CoA.
C the rate of oxidative phosphorylation.
D feedback inhibition by H2O.
E the catalytic rate of cytochrome oxidase. 62. Which of the following experimental observations would not support the
chemiosmotic model of oxidative phosphorylation?
A If mitochondrial membranes are ruptured, oxidative phosphorylation cannot occur.
B Raising the pH of the fluid in the intermembrane space results in ATP synthesis in
C Transfer of electrons through the respiratory chain results in formation of a proton
gradient across the inner mitochondrial membrane.
D The orientation of the enzyme complexes of the electron transfer chain results in a
E Radioactively labeled inorganic phosphate is incorporated into cytosolic ATP only
in the presence of an H+ gradient across the inner mitochondrial membrane.
63.Indicate whether each of the following statements about the mitochondrial
electron transfer chain and oxidative phosphorylation is true (T) or false (F).
A NADH dehydrogenase complex, cytochrome bc1 complex, and cytochrome
B Synthesized ATP must be transported into the intermembrane space before it can
C Cytochrome c and the F1 part of ATPase are peripheral membrane protein. D Complexes I, II, III, and IV all are proton pumps. E Ubiquinone is a hydrophilic molecule. F Ubiquinone and the Fo part of ATP synthase are both peripheral membrane
G The final electron acceptor is H2O. 64. In order to examine the citric acid cycle you have obtained a pure
preparation of isolated, intact mitochondria. You add some succinyl-CoA to the
suspension of mitochondria. How many moles of ATP would you expect to be
generated in one turn of the citric acid cycle from each mole of succinyl-CoA
added to the test tube?
5) No ATP would form under these conditions. 65. A patient has sporadic bouts of fainting that are found to correlate with
hypoglycemic episodes. The hypoglycemia is easily cured by ingestion of food.
There is a history of this ailment in the patient's family. The most likely
explanation is a defect in
A GLUT4 transporter
B insulin receptor
C liver glycogen synthase
D muscle glycogen phosphorylase(e) muscle 6-phosphofructo-1-kinase 66. Glucose uptake by skeletal muscle is increased by exercise because of an
increase in the intracellular concentration of
D creatine phosphate
E NADH 67. Relative to the well-fed state, which of the following is increased in the liver
in the starved state?
A AMP concentration
B Fructose-2,6-bisphosphatase activity
C Pyruvate dehydrogenase activity
D Pyruvate kinase activity 68. The synthesis of glycogen, starch and lactose
A. uses glucose-1-phosphate as the only substrate.
B. uses a sugar nucleotide as a substrate.
C. only takes place in the liver of mammals.
D. involves the addition of a sugar residue at the reducing end of the a
growing polymer. 69. An enzyme used in both glycolysis and gluconeogensis is:
C. phosphoglycerate kinase
D. pyruvate carboxylase
E. phosphofructokinase 70. One cycle of the citric acid cycle produces ______ moles of NADH,_____
moles of FADH2 and _____ moles of GTP :
A. 3; 2; 0
B. 4; 2; 1
C. 3; 1; 1
D. 2; 2; 2 71. Which list of intermediates is in the correct order for the part of citric acid
cycle that includes these intermediates?
A. succinyl-CoA, succinate, a-ketoglutarate, fumarate, malate
B. a-ketoglutarate, succinyl-CoA, succinate, fumarate, malate
C. succinate, succinyl-CoA, fumarate, a-ketoglutarate, malate
D. a-ketoglutarate, succinyl-CoA, succinate, malate, fumarate
E. a-ketoglutarate, malate, fumarate, succinyl-CoA, succinate 72. In glycolysis, substrate level phosphorylation is catalyzed by:
B. glyceraldehyde 3-phosphate dehydrogenase
D. phosphoglycerate kinase 73. The first step of gluconeogensis is catalyzed by:
B. pyruvate carboxylase
C. PEP carboxykinase
D. pyruvate kinase 74.The reaction catalyzed by the pyruvate dehydrogenase complex can be
divided all of the following stages except:
D. regeneration of cofactors
E. all are stages in the reaction 75. Which of the following statements is correct about lactate
A. it is the dead end product of anaerobic respiration in the muscle and liver
B. it is transported from the muscle to the liver where it enters glycolysis
C. it is transported from the liver to the muscle where it enters the citric acid cycle
D. it is transported from the muscle to the liver where it is converted to glucose via
76. Animals can’t catalyze the net conversion of acetyl CoA into carbohydrates
A. synthesis pathways occur in the cytosol while the degradation pathways that occur
B. there is a net lose of two molecules of CO2 in the citric acid cycle C. acetyl CoA can not be converted to oxaloacetate D. there are no metabolic pathways that connect pathways that form acetyl CoA with
77. Which of the following enzymes found in the citric acid cycle is a membrane
B. Succinate dehydrogenase
C. Succinyl CoA Synthetase
D. Malate dehydrogenase 78. Which of the following is not correct concerning the isomerization of
citrate to isocitrate:
A. the enzyme contains a unique Fe-S cluster.
B. converts a tertiary alcohol ( which can not be oxidized) to a secondary alcohol that
C. it is a major control step in the citric acid cycle
D. all are correct 79. The two main purposes of the citric acid cycle are:
A. synthesis of citrate and gluconeogenesis
B. degradation of acetyl Co A to produce energy and supply of precursors for
C. degradation of pyruvate to produce energy and supply of precursors for
D. degradation of acetyl Co A to produce energy and gluconeogenesis 80. Gluconeogenesis takes place predominantly in the
E. liver 81. Biotin functions as a:
A. carrier of activated aldehydes
B. carrier of activated carbon dioxide
C. carrier of activated electrons
D. carrier of activated acyl groups 82. What are the most important products that cells generate by means of
the pentose phosphate pathway?
A. lactate and ATP
B. ribose-5-phosphate and NADPH
C. NADP+ and ribose-5-phosphate
D. NADPH and UDP-ribose
E. ribulose-1,5-bisphosphate and NADPH 83. Which combination of cofactors is involved in the conversion of pyruvate to
A. NAD+, biotin, and TPP, and Co A
B. TPP, Co A, lipoic acid, NAD+ and FAD
C. pyridoxal phosphate, FAD and lipoic acid,
D. biotin, FAD, and TPP
E. biotin, NAD+, and FAD 84. In a eukaryotic cell, the enzymes of glycolysis are located in the ____ and the
enzymes of the TCA cycle are located in the ____:
A plasma membrane, cytosol.
B cytosol, mitochondrial matrix. C
cytosol, mitochondrial matrix and membrane.
D nucleus, cytosol. 85. Which of the following compound is responsible for coordinated regulation of
glycolysis and gluconeogenesis?
C fructose 2,6 bis phosphate
D fructose 1,6 bis phosphate 86.A lack of phosphoglucomutase activity is most likely to produce a deficiency
B. ribose 5-phosphate
E. glycogen 87. Approximately 10% of the glucose derived from glycogen and released from
the liver during fasting is produced directly (not generated via the action of
glucose-6-phosphatase) by which of the following enzymes?
A. Glycogen phosphorylase
B. Debranching enzyme
C. Branching enzyme
D. Glycogen synthase
E. UTP/glucose 1-phosphate pyrophosphorylase 88. Which if the following enzymes forms alpha-1, 6 linkages in glycogen?
A. glycogen phosphorylase
B. glycogen branching enzyme
C. amylo-(1,6) glucosidase
D. phosphorylase kinase
E. glucose 6-phosphatase 89. Which enzyme is present in the liver but NOT in the muscle?
B. glucose 6-phosphatase
C. lactate dehydrogenase
D. pyruvate dehydrogenase
E. glycogen phosphorylase 90. Gluconeogenesis from lactate does not require activity of
C. glyceraldehyde 3-phosphate dehydrogenase
D triose phosphate isomerase
E. phosphoglycerate kinase 91. Which compound does NOT contribute to the net formation of glucose
during gluconeogenesis in humans?
E. alanine 92. Which of the following describes the mechanism by which NADH generated
in the cytoplasm donates electrons to oxygen via the mitochondrial electron
A. A specific transport system enables NADH to pass through themitochondrial
B. NADH reduces cytoplasmic FAD to FADH2, which passes through the
C. NADH reduces cytoplasmic dihyroxyacetone phosphate to glycerol phosphate,
which is reoxidized by an enzyme associated with the mitochondrial electron transport system.
D. NADH reduces cytoplasmic NADP to NADPH, which can enter the mitochondria.
E. None of the above mechanism is used. 93. Mammals cannot achieve a NET synthesis of glucose from fatty acids due to
the inability to convert
A. acetyl-CoA to acetoacetate.
B. acetyl-CoA to pyruvate.
C. oxaloacetate to pyruvate.
D. acetyl-CoA to malonyl CoA.
E. methylmalonyl-CoA to succinyl-CoA. 94. The immediate products of oxidation of one mole of glucose 6-phosphate
through the oxidative portion of the pentose phosphate pathway are:
A. one mole of ribulose 5-phosphate, one mole of CO2 and two moles of NAD.
B. one mole of ribulose 5-phosphate, one mole of CO2 and two moles of NADPH.
C. one mole of xylulose 5-phosphate, one mole of CO2 and two moles of NADPH.
D. one mole of ribose 5-phosphate, one mole of CO2 and two moles of NADPH.
F. one mole of fructose 6-phosphate and two moles of NADP. 95. The enzyme transketolase is a component of
A. the TCA cycle.
B. the pentose pathway.
C. fatty acid synthase.
D. the pyruvate dehydrogenase complex.
E. none of the above 96. Glycolysis
A. Takes place in the mitochondrion
B. Is the major provider of ATP to muscle during heavy exercise
C. Is controlled by levels of fructose-2,6 bis phosphate
D. Is the only pathway known from glucose to pyruvate 97. Glycogen phosphorylase
A. Responds oppositely to epinephrine in liver and muscle
B. Is phosphorylated by protein kinase A
C. Has an R and T form that are stabilized by AMP and ATP, respectively
D. Is phosphorylated in response to cyclic AMP and Ca2+ 98. The citric acid cycle
A. Oxidizes acetate to CO2 and water
B. Provides intermediates for amino acid, porphyrin and carbohydrate biosynthesis
C. Can accomplish net synthesis of succinate from acetylCoA
D. Can be replenished by carboxylation of PEP 99. Which one of the following statements about gluconeogenesis in animal cells
A the conversion of glucose-6-phosphate to glucose is catalyzed by hexokinase.
B the conversion of phosphoenolpyruvate to 2-phosphoglycerate occurs in two steps,
C the conversion of fructose-1,6-bisphosphate to fructose-6-phosphate is not
catalyzed by phosphofructokinase, the enzyme involved in glycolysis.
D an animal fed a large excess of fat in the diet will convert any fat not needed for
E production into glycogen for later use.
F gluconeogenesis helps to reduce blood glucose after a carbohydrate-rich meal. 100. Which of the following is true of glucagon (in liver) and epinephrine (in
A they both activate glycogen phosphorylase andinactivate glycogen synthase.
B they both inhibit glycogen synthesis and activate glycogen breakdown.
C they act by raising the concentration of cAMP.
D they oppose the effects of insulin on these tissues.
E all of the above. 101. Phosphorylation activates all of the following except:
A glycogen phosphorylase
B phosphoprotein phosphatase inhibitor
C phosphoprotein phosphatase
D triacylglycerol lipase
E phosphorylase kinase 102. A common moiety for NADP, NAD, FMN, FAD, and coenzyme A is:
A. A pyrimidine ring;
B. A three ring structure;
C. An ADP;
D. A pyranose ring;
E. A triphosphate group. 103. If the C-1 carbon of glucose were labeled with 14C, which of the carbon
atoms in pyruvate would be labeled after glycolysis?
A. The carboxylate carbon;
B. The carbonyl carbon;
C. The methyl carbon. 104. Which of the following are metabolic products of pyruvate in higher
B. Lactic acid
E. Ethanol 105. Indicate whether each of the following statements about the pentose
phosphate pathway is true
A. It generates NADH for reductive biosyntheses.
B. The reactions occur in the cytosol.
C. Transketolase and transaldolase link this pathway to gluconeogenesis.
D. It is more active in muscle cells than in fat-storage cells.
E. It interconverts trioses, tetroses, pentoses, hexoses, and heptoses. 106. Which of the following statements about the citric acid cycle are correct?
A. does not exist as such in plants and bacteria, because its functions are performed
B. oxidizes acetyl CoA derived from fatty acid degradation.
C. produces most of the CO2 in anaerobic organisms.
D. provides succinyl CoA for the synthesis of carbohydrates.
E. provides precursors for the synthesis of glutamic and aspartic acids. 107.Indicate whether each of the following statements about the glyoxylate cycle
A. It allows the products of fatty acid oxidation to be converted, eventually, to
B. It provides intermediates for the citric acid cycle during periods when amino acids
C. It depletes cellular stores of oxaloacetate.
D. It occurs instead of the citric acid cycle in plants. 108.Which statement is NOT true of phosphofructokinase-1?
A. It is inhibited by fructose-2,6-bisphosphate.
B. It is activated by AMP.
C. It is inhibited by citrate.
D. It is inhibited by ATP.
E. ATP increases its K0.5 for fructose 6-phosphate. 109.All of the following statements describe glycolysis EXCEPT:
A. It produces a net of 2 ATP molecules for each molecule of glucose.
B. Its rate is mainly regulated by hexokinase.
C. The glycolytic enzymes are found in the cytosol.
D. Two molecules of glyceraldehydes 3-phosphate are produced for each glucose
E. Its overall rate is regulated by the energy level of the cell. 110. A lack of phosphoglucomutase activity is most likely to produce a deficiency
A. pyruvate B. ribose 5-phosphate C. NADP D. NADH E. glycogen 111.Which of the following statements is not correct about the reactions
catalyzed by pyruvate dehydrogenase?
A. It is a multienzyme complex that catalyzes 5 reactions using 3 enzymes and 5
B. TPP , lipoamide and FAD are tightly associated with the enzyme complexes C. The purpose of reactions 4 and 5 is to recycle the cofactors D. The extended side chain of the prosthetic group lipoamide moves between the
various active sites allowing the transfer of intermediates between the three enzymes.
E.All of the statements are correct concerning pyruvate dehydrogenase 112.Which of the following statements is TRUE of muscle glycogen
A. It degrades glycogen to form glucose-1-phosphate.
B. It removes glucose residues from the non-reducing ends of glycogen chains.
C. It catalyzes phosphorolysis of b(1?6) bonds of glycogen.
D. All of the above are correct concerning muscle glycogen phosphorylase
E. None of the above are correct concerning muscle glycogen phosphorylase 113. Gluconeogenesis is the synthesis of:
A. glucose from non-carbohydrate precursors
B. glycogen from glucose
C. pyruvate from glucose
D. fatty acids from glucose 114. Which of the following enzymes catalyzes a REVERSIBLE reaction in vivo?
B. pyruvate kinase
C. phosphoglycerate kinase
E. None of these enzymes catalyze a reversible reaction in vivo. 115. The glycogen synthase uses _____ as the substrate for glycogen synthesis,
D. glucose 116. The primary regulatory enzyme for glycolysis is:
A. glycogen phosphorylase
D. phosphoglucomutase 117. Which of the following statements about NAD+ and FAD is correct?
A. Each can accept 2 electrons, 1 electron at a time.
B. Each can accepts electrons only in 2 electron transfers
C. NAD+ accepts only 2 electrons at a time while FAD can accept 1 electron at a
D. FAD accepts only 2 electrons at a time while NAD+ can accept 1 electron at a
E. None of the statements are correct. 118. Which of the following is the central intermediate that links several
carbohydrate metabolic pathways?
B. glucose 1-phosphate
C. glucose 6-phosphate
E.glucose 1, 6 bisphosphate
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