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0.25__A___ 1. A competitive inhibitor of an enzyme:
A. increases Km without affecting V max
B. decreases Km without affecting V max
C. increases V max without affecting Km
D. decreases V max without affecting Km
0.50___D__ 2. The Michaelis constant, Km is:
A. numerically equal to ½ V max
B. dependent on the enzyme concentration
C. independent pH
D. numerically equal to the substrate concentration that gives half-maxiaml
velocity.
0.25__D___ 3. The rate of an enzyme-catalyzed reaction was measured using several substrate concentrations that were
much lower the Km. The dependence of reaction velocity on substrate concentration can best be described as:
A. independent of enzyme concentration
B. a constant fraction of V max
C. equal to Km
D. proportional to the substrate concentration
0.50__D___ 4. Which of the following statements is NOT characteristic of allosteric enzymes?
A. they frequently catalyze a committed step early in a metabolic pathway
B. they are often composed of subunits
C. they frequently show cooperativity for substrate binding
D. they follow Michaelis-Menten kinetics
0.50__B___ 5. The presence of a non competitive inhibitor:
A. leads to both an increase in the V max of a reaction and increase in the Km
B. leads to a decrease in the observed V max
C. leads to a decrease in Km and V max
D. leads to an increase in Km without affecting V max
Biochemistry 2nd edition
lippincotts illustrated reviews
(Pamela c. champe / Richard a. Harvey
p 60-61
1.0__B___ 6. The property of an enzyme to catalyze a given chemical reaction is an intrinsic function of its:
A. concentration
D. electrophoretic mobility
B. conformation
E. isoelectric pH
C. amphoteric nature
0.50__A___ 7. The hyperbolic relationship between initial velocity and [S] concentration is described by the equation:
A. v=Vmax [S]/ Km + [S]
B. v=Km + [S]/Vmax [S]
C. v=Km [S]/Vmax + [S]
D. v=Vmax [S]/Km [S]
1.0__B___ 8. Plotting initial velocity against various pH values in an enzyme-catalyzed reaction gives:
A. A hyperbolic curve
B. A bell-shaped curve
C. A linear plot
D. A sigmoid curve
0.25__C___ 9. True of active site in enzyme, EXCEPT:
A. it is the only site for catalysis
B. it is the binding site for [S]
C. its catalytic residues are sequentially arranged in relation to its primary structure.
D. Its shape generally complements the shape of the substrate
E. A competitive inhibitor competes with the substrate to bind to it.
0.50__D___10. Isoenzymes are utilized as markers in the diagnosis of certain clinical conditions because:
A. of their high catalytic activity
B. of the unique combination of their subunits in forming the active polymeric especies
C. they are present in significant concentration in specific cells
D. they exhibit optimum activity within a very narrow pH range
E. they differ in their electrophoretic rates of migration
Biochemistry by harpers
0.25___C___11. TRUE regarding anomerism:
A. Anomeric carbon for aldose, is Carbon 2
B. Anomeric carbon for ketose, is Carbon 1
C. In the alpha anomer the OH attached to the anomeric carbon is pointing to the right on
Fischer’s structure and located downward in Haworth’s projection formula.
D. All of the above
1.0__B____12. The chief constituent of fibrous part of plants, is:
A. Starch
B. Cellulose
C. Chitin
D. Peptidoglycan
0.25__C____13. Not true of osazone formation:
A. There should be a free carbonyl group
B. Mannose, fructose and glucose have the same osazone crystals
C. This test could differentiate galactose from glucose
D. Osazone crystals are soluble in strong alkali medium
0.50___D___14. Not true about a glycosidic bond:
A. Acted upon by specific glucosidases
B. May either be in L or D form
C. Broken down by boiling with acids
D. Is stable in an alkaline medium
0.50___A___15. D-glucose and L-glucose are stereoisomers; they are called as such due to;
A. Their relationship to the D and L glycerose
B. The conformation on their anomeric carbon
C. The direction of optical activity
D. All of the above
0.50___B___16. True regarding sucrose:
A. It has a free carboxyl group
B. It is a non-reducing sugar
C. It is also known as sucrase
D. All of the above
1.0___B___17. A sugar alcohol that is implicated in the causation of cataract in galactosemia, is:
A. Mannitol
B. Galactitol
C. Sorbitol
D. All of the above
1.0___D___18. A keto sugar;
A. Galactose
B. Glucose
C. Mannose
D. Fructose
1.0___B___19.D-glucose and D-mannose are:
A. Anomers of each other
B. Epimers of each other
C. Enantiomers of each other
D. All of the above
1.0___D___20. Not true of Lactose:
A. A reducing sugar
B. Hydrolyzed by beta-glycosidase
C. Not fermentable by yeast
D. Has free carbonyl group at the galaxies moiety
Introduction to Molecular Medicine:
Choose the best answer:
0.5__C___21. Which technique can be use to analyze protein:
A. Maxam-Gilbert B. Sanger’s method C. Western blot
D. RFLP
0.5___A__22. Coding region in DNA
A. Exon B. Intron C. probe D. primer
0.25___D__23. What is the key tool for recombinant DNA technology?
A. DNA polymerase
B. Topoisomerase
C. Phosphatase
D. restriction enzyme
0.75___C__24. What is the machinery for DNA cloning?
A. Translation
B. transcription
C. Replication
D. reverse transcription
0.25__A___25. What is the machinery for cloning cells?
A. Cell cycle
B. mitosis
C. Meiosis
D. DNA replication
0.5__B___26. Restriction enzymes are used by this organism to defend themselves.
A. Viruses
B. bacteria
C. Fungi
D. Mycoplasma
1.0__A___27. A blot technique that is involved in the analysis of DNA:
A. Southern blot B. Northern blot C. Western blot
D. Eastern blot
1.0__C___28. When cloning a DNA fragment with a length of 400,000 bp, the appropriate vector is:
A. Plasmid
B. Lambda
C. Cosmid
D. YAC
0.5__D___29. Which of the following enzyme is not required for the synthesis of cDNA ?
A. reverse transcriptase
B. Rnase H
C. DNA ligase
D. Dnase 1
0.25__A___30. What method is based on the preparation of large arrays of oligonucleotides
on miniaturized solid supports for analysis of DNA sequence?
A. DNA chips(microarray)
B. RFLP
C. Southern blot
D. PCR
1.0__D___31. Which of the following enzymes does not form phosphodiester bonds?
A. DNA ligase
B. DNA polymerase
C. RNA polymerase
D. Dnase 1
0.25__C___32. Which of the following features of the vector will allow screening for host
cells that were transformed with the recombinant DNA construct?
A. OriC sequence
B. Promoter sequence
C. Antibiotic resistance gene
D. Restriction site
Reference:
1. Harper’s Biochemistry
2. Molecular Biology of the Cell by Alberts
Gene Expression:
Choose the best answer:
0.5__B___33. The following are TRUE regarding DNA replication, EXCEPT:
A. Semiconservative
B. Unidirectional
C. Continous synthesis of the leading strand
D. Discontinous synthesis of the lagging strand
1.0__C___34. Replication involves which of the following:
A. Peptide bond formation
B. Synthesis of RNA
C. Synthesis of a new DNA strand
D. Synthesis of proteins
0.5___B__35. Which enzyme is involved in DNA repair:
A. DNA polymerase III
B. DNA polymerase I
D. Taq polymerase
C. DNA polymerase II
0.5__A___36. The supercoiling of DNA is relieved by the action of:
A. topoisomerases
B. helicases
C. DNA ligase
D. SSB
0.5__D___37. What anchors the mRNA to the 16S rRNA of the ribosome during translation?
A. Kozak sequence
B. Promoter
C. Initiation codon
D. Shine-dalgarno sequence
0.5__A___38. The initiation codon is found in the ____ in eukaryotes:
A. Kozak sequence
B. Shine-dalgarno sequence
C. Promoter
D. Enhancer
0.5__C___39. The termination signal for transcription involves:
A. hairpin loop + poly-A-tract
C. Both
B. hairpin loop + Rho factor
D. Neither
1.0___D__40. The termination of translation is signified by:
A. ter regions
C. tus
B. rho factor
D. stop codons
1.0__A___41. The main enzyme that removes the RNA primer during replication is the:
A. DNA polymerase I
C. DNA polymerase III
B. DNA polymerase II
D. RNA polymerase
1.0___B___ 42. Which part in the tRNA contains the invariant CCA and the binding site for amino acids?
A. Anticodon arm
C. V arm
B. Acceptor arm
D. TψC arm
Reference:1. Harper’s Biochemistry
0.5__A___ 43. Factor(s) that prevent(s) alpha-helix formation in a protein:
A. Presence of Proline
B. Presence of adjacent Aspartic acid and Argenine in the chain
C. Presence of adjacent Valine and Alanine in the chain
D. All of the above
( ref.: Harper’s Illustrated Biochemistry,26th ed.pp.31-32)
0.5___C__ 44. This inborn error of metabolism is manifested by damage to the arterial walls,
skeletal deformities and convulsive seizures:
A. Hartnup disease
C. Homocystinuria
B. Cystathioninuria
D. Cystinosis
( ref.: Biochemistry-Lippincott’s Illustrated Review’s 2nd ed.p528)
0.5____D__ 45. True regarding Phenylalanine:
A. It is the source of the naturally occurring tranquilizer of the body
B. It can be converted to Tyrosine thru decarboxylation
C. It is the source of a hormone that is used to induce sleep
D. It is the source of the pigment responsible for our complexion
(ref: Principles of Biochemistry-Lehninger,Nelson 2nd ed.p.528)
0.5____B__ 46. Hydrogen bonding can exist between the R groups of:
A. Glutamic acid and glutamine
C. Serine and asparagines
B. Cysteine and tyrosine
D. Aspartic acid and Lysine
(ref:Principles of Biochemistry-Lehninger,2nd ed. P162-163)
0.75___D___ 47. Inborn errors of urea synthesis manifested by hyperammonemia:
A. deficiency of carbamoyl PO4 synthetase
B. deficiency of argininosuccinase
C. deficiency of ornithine transcarbamylase
D. all of the above
(ref: Txtbook of Biochemistry with Clinical Correlations-Devlin, 4th edition p445-457)
0.5___C___ 48. True regarding the urea cycle:
A. The synthesis of citrulline takes place in the cytosol
B. The second ammonia that is detoxified thru the cycle enters at the level of arginine
C. Arginase is a major control enzyme of the pathway
D. All of the above
(ref: Harper’s Illustrated Biochemistry,26th ed.pp245-247)
0.75___A___ 49. Regarding the levels of protein structure:
A. The primary structure is maintained by peptide bonds between amino acids
B. The second structure is maintained by R to R interactions
C. The tertiary structure is maintained by hydrogen bonding between peptide bonds
D. The quarternary structure is exhibited by all proteins
(ref: Harper’s Illustrated Biochemistry,26th ed. P31-35)
0.75___C-__ 50. Glycolysis , glycogenesis and lipogenesis are stimulated by this hormone:
A. glucagons
B. cortisol
C. insulin D. epinephrine
(ref:Harper’s Illustrated Biochemistry,26th ed,pp 155-157,160-162,178-179)
0.5___A___ 51. Interconversion of sugars in the HMP shunt is made possible thru this enzyme:
A. transketolase
C. Glucose-6-PO4 dehydrogenase
B. aldolase
D. Glucose-6-phosphatase
(ref: Harper’s Illustrated Biochemistry,26th ed.pp 163-166)
1.0___B___ 52 It is an amphibolic pathway and regarded as the final common pathway of metabolism:
A. Embden-Meyerhof pathway
C. Glycogenesis
B. Citric acid cycle
D. Krebs-Henseleit cycle
(ref: Harper’s illustrated Biochemistry , 26th ed ,pp130-135)
0.75___D___ 53. All of the following enzymes catalyze substrate level of phosphorylation, EXCEPT:
A. succinate thiokinase
C. phosphoglycerate kinase
B. pyruvate kinase
D. phosphofructokinase
(ref: Biochemistry: Lippincott’s Illustrated Reviews , 2nd ed.pp92-108)
0.25___C___ 54. The energy generation phase of glycolysis starts with this reaction:
A. conversion of glucose to glucose-6-PO4
B. conversion of fructose to fructose-6-phosphate
C. conversion of fructose-6-PO4 to DHAP and glycealdehyde-3-phosphate
D. conversion of glyceraldehydes-3-phosphate to 1,3-diphosphoglycerate
(ref: Harper’s Illustrated Biochemistry , 26th ed.pp136-143)
0.5___B___ 55. Complete oxidation of one mole of glucose using the malate aspartate shuttle will yield how many
moles of ATP (NET):
A. 40
B. 38
C. 36
D.24
E. 12
(ref: Harpers illustrated Biochemistry,26th ed. Pp142-143)
0.75___C__ 56. This cycle recycles lactate formed in the muscles back to glucose in the liver:
A. Anaerobic glycolysis
C. Cori cycle
B. Uronic acid pathway
D. Glucose-alanine cycle
(ref: Harper’s Illustrated Biochemistry,26th ed.p159)
0.75___D___ 57. True regarding Vitamin B12:
A. It is only found in animal sources
B. Deficiency develops if a person undergoes total gastroectomy
C. It cannot be given in large doses for long periods of time because it causes toxicity
D. All statements are correct
( ref: Harper’s Illustrated Biochemistry,26th ed. pp 491-492)
0.5___A___ 58. Function of Vitamin C:
A. regulates cholesterol metabolism by promoting its excretion
B. Prevents infection by strengthening the barrier that prevents the entry of microorganism
C. Prevents destruction of carotenes and vitamin A
D. Increase absorption of calcium and phosphorous in the small intestines
( ref: Harper’s Illustrated Biochemistry,26th ed.pp495-496)
0.75__B____ 59. True regarding Vitamin D:
A. its activation involves a 2 step reduction process
B. it can be synthesized from cholesterol in the presence of sunlight
C. deficiency can cause keratomalacia
D. its most active form is synthesized in the liver
(ref: Harper’s Illustrated Biochemistry,26th ed.pp 484-485)
0.5___C___ 60. Function(s) of Vitamin B6;
A. co-enzyme in the rate-limiting step of the Kreb’s cycle
B. coenzyme in the committed step of glycolysis
C. coenzyme in heme synthesis
D. all of the above
(ref: Harper’s illustrated Biochemistry,26th ed.p491)
0.5___B___ 61. Pantothetic acid is an energy-releasing vitamin because:
A. it is involved in glycolysis
B. it is involved in the Kreb’s cycle
C. it is involved in steroid hormone synthesis
D. it is involved in the HMP shunt
(ref: Harper’s Illustrated Biochemistry,26th ed. p495)
1.0___A_____ 62. People who are fond of eating raw fish, raw clams and oysters may develop deficiency of this
vitamin:
A. Thiamine
B. Riboflavin
C. Niacin D. Pyridoxine
( ref: textbook of Biochemistry with Clinical Correlations-Devlin 4th
ed. pp 1118-1120)
0.50___B____ 63. Which of the following acts as surface antigens?
A. prostaglandins
B. glycoshingolipids
C. dolichols
D. lecithin
0.50____A___ 64. Which of the following acts as lung surfactant?
A. phosphatidylcholine
B. phosphatidylinositol
C. phosphatidylserine
D. phosphatidylethanolamine
0.75___A____ 65. Which of the following is/are omega-6 fatty acids?
A. linoleic acid
B. docosahexaenoic acid
C. eicosapentaenoic acid (EPA)
D. linolenic acid
0.50____B___ 66. Which of the following is/are lipid components of all biological membranes?
A. free fatty acid
B. cholesterol
C. triglyceride
D. ganglioside
0.25___A____ 67. Which of the following fatty acids would exhibit the lowest melting temperature?
A. Linolenic acid
B. Linoleic acid
C. Oleic acid
D. Palmitic acid
0.50____C___ 68. Structural characteristics of the sphingomyelins include:
A. ceramide and sphingosine
B. sphingosine, ethanolamine and phsphatidic acid
C. ceramide and phosphorylcholine
D. sphingosine and phosphorylserine
0.50_____B___ 69. Lipoprotein density is directly proportional to its:
A. cholesterol content
B. protein content
C. TAG content
D. Phospholipid content
0.50____D_____ 70. The enzyme that hydrolyzes TAG in VLDL and chylomicra is:
A. hormone-sensitive lipase
B. pancreatic lipase
C. gastric lipase
D. lipoprotein lipase
0.75_____D____ 71. The cyclooxygenase pathway synthesizes:
A. Prostaglandins
B. Leukotrienes
C. Thromboxanes
D. A & C
0.75___D_____ 72. Ketone bodies are oxidized for ATP generation via:
A. Beta-oxidation pathway
B. Cyclooxygenase pathway
C. Lipoxygenase pathway
D. Kreb’s citric acid cycle
0.75____D____ 73. Ketonemia arising from the utilization of fat as the major alternative source of energy occurs in:
A. diabetes mellitus
B. starvation
C. prolonged consumption of high fat diet
D. all of the above
0.50____D____ 74. Glycerol phosphate, the backbone of TAG, is synthesized in the liver by:
A. phosphorylation of glycerol by glycerol kinase
B. phosphorylation of diacylglycerol
C. reduction of dihydroxyacetone phosphate
D. A & C are correct
0.75____C____ 75. True of the beta-oxidation of palmitic acid, EXCEPT:
A. occurs in the matrix of mitochondria
B. two oxidation steps generate 5 mols of ATP per cycle
C. cleavage reaction occurs between the beta and gamma carbons
D. the cell conserves 129 moles ATP per mole of palmitic acid
0.75____D____ 76. Utilizes ketone bodies for energy, EXCEPT:
A. skeletal muscles
B. brain
C. cardiac muscles
D. liver
1.00____B____ 77. The rate-limiting enzyme in the biosynthesis of cholesterol is:
A. HMG-CoA oxidase
B. HMG-CoA reductase
C. HMG-CoA synthase
D. HMG-CoA lyase
1.00___D_____ 78. Which of the following molecule is the largest energy reserve of the human body in terms of
kilocalories?
A. muscle glycogen
B. muscle triglycerides
C. liver glycogen
D. adipose tissue triglycerides
0.75____D____ 79. Increased fatty acid oxidation occurs during,
A. starvation
B. diabetes mellitus
C. diabetes insipidus
D. A & B
0.50_____D___ 80. Ketone bodies,
A. consist of acetoacetate, acetone, hydroxybutyrate
B. are important fuels in extrahepatic tissues.
C. are derived from fatty acids
D. all of the above
0.50____D____ 81. Which of the following is/are true regarding VLDL?
A. packaged in the liver cell
B. hydrolysis of its TAG gives rise to LDL
C. major vehicle of transport of endogenous TAG in Blood
D. all of the above
0.25___B____ 82. Which of the following activates lipoprotein lipase?
A. Apo E
B. ApoCII
C. Apo B
D. None of the above
0.75___C___ 83. Glycolysis, glycogenesis and lipogenesis are stimulated by this hormone:
A. glucagons
B. cortisol
C. insulin
D. epinephrine
0.50___D___ 84. Effects of insulin:
A. Mobilizes the glucose transporters from the Gogi apparatus to the cell membrane
B. Stimulates pyruvate kinase and glucokinase
C. Inhibits cyclic AMP
D. All of the above
0.50___C___ 85. What is the second messenger of growth hormone?
A. cyclic-AMP
B. Ca/phosphoinositides
C. Kinase/phosphatase cascade
D. None of the above
0.75___A___ 86. Which of the following is/are cell associated recognition molecules?
A. receptors
B. hormones
C. protein kinase
D. none of the above
0.75___D___ 87. Hormones are synthesized,
A. in one tissue transported to act on another organ
B. by cells of epithelial origin
C. by cells strategically located for a specific action
D. all of the above
0.75___C___ 88. The following are hormone-related diseases EXCEPT,
A. bronchial asthma
B. grave’s disease
C. pertussis
D. myasthenia gravis
0.25___C___ 89. Which of the following is not a nanopeptide hormones?
A. vasopressin
B. oxytocin
C. corticotropin
D. none of the above
0.50___C___ 90. Cholera toxin causes ADP ribosylation of which subunit of G-proteins?
A. gamma
B. beta
C. alpha
D. none of the above
0.50___C___ 91. Which of the following is/are amino acid derived hormones?
A. growth hormone
B. parathyroid hormone
C. thyroid hormone
D. none of the above
0.75___B___ 92. Which of the following is/are released by nipple stimulation?
A. vasopressin
B. oxytocin
C. neurophysin
D. none of the above
0.75___B___ 93. Which of the following is a modified amino-acid hormones?
A. growth hormone
B. thyroid hormone
C. parathyroid hormone
D. none of the above
0.25___D___ 94. Which of the following is not a coupled system?
A. CRH-ACTH-cortisol
B. TRH-TSH-T3/T4
C. GnRH-LH/FSH-testosterone/estradiol/progesterone
D. None of the above
0.50___B___ 95. Which of the following transport hormones from the hypothalamus through the axons to the posterior
pituitary?
A. endorphins
B. neurophysins
C. vasopressin
D. none of the above
0.75___A____ 96. Which of the following is released by changes in serum osmolality?
A. antidiuretic hormone
B. parathyroid hormone
C. oxytocin
D. None of the above
0.75___C____ 97. Which of the following is released by nipple stimulation?
A. vasopressin
B. neurophysin
C. oxytocin
D. none of the above
0.50____C___98 The coupling of two iodinated tyrosyls form _____.
A. tyrosine
B. thyroglobulin
C. iodothyronine
D. none of the above
0.50____B___ 99. Which of the following forms of calcium is/are biologically active?
A. complexed with organic acids
B. ionized
C. protein bound
D. none of the above
0.25___A____ 100. Which of the following organs contain parathyroid hormone receptors?
A. kidney
B. muscle
C. liver
D. none of the above
END OF EXAM !!!