Biochem Block 1 Practice Q's

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Biochem Block 1 Practice Q's
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Biochemistry Block 1 practice questions
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  1. Which one of the following bonds or interactions is stronger in the presence of water than in its absence?

    A. Hydrogen bond
    B. Hydrophobic interactions
    C. Electrostatic interactions
    D. Association between sodium
    ions and chloride ions Dipole-dipole interaction
    B. Hydrophobic interactions
  2. Water can simultaneously form _____ hydrogen bonds.

    A. 1
    B. 2
    C. 3
    D. 4
    E. 5
    D. 4
  3. Which one of the following can form a micelle in water?

    A. Alanine
    B. Ethanol
    C. Hexane
    D. Oleate
    E. Sodium chloride
    F. Leucine
    D. Oleate
  4. Which one of the following exhibits restricted
    rotation around a bond within the molecule or around the specified linkage?

    A. Chlorobromohydroxymethane
    B. A disulfide bond
    C. Cis 2-butene
    D. Trans 2-butene
    E. An ester linkage
    • C. Cis 2-butene
    • D. Trans 2-butene
  5. Which of the following functional groups is basic when placed in water?

    A. Amide
    B. Amine
    C. Ester
    D. Alcohol
    E. Sulfhydryl group
    B. Amine
  6. Which amino acid has a benzene ring with an OH group attached to it in its side chain?

    A. Tyrosine
    B. Tryptophan
    C. Leucine
    D. Asparagine
    E. Glutamic acid
    F. Alanine
    G. Valine
    A. Tyrosine
  7. Which amino acid has a negatively charged side chain?

    A. Aspartic acid
    B. Glutamine
    C. Histidine
    D. Serine
    E. Tyrosine
    F. Leucine
    G. Lysine
    A. Aspartic acid
  8. What is the net charge on serine at pH 1, 6 and 11?

    1.
    6.
    11.
    • 1. +1
    • 6. 0
    • 11. -1
  9. In the figure above which letter corresponds to the region closest to the (1) pI, (2) the pKa of the most acidic group, (3) Gly in its fully protonated form (4) the titration of the amino group?



    1.
    2.
    3.
    4.
    • 1. C
    • 2. B
    • 3. A
    • 4. D
  10. What is the major force or bond holding _____
    together?

    a. Alpha helix –
    b. Beta sheet –
    c. Protein primary structure –
    d. Secondary structure –
    e. Supersecondary structure –
    f. Tertiary structure -
    g. Hemoglobin subunits –

    1. hydrophobic interactions
    2. hydrogen bonds
    3. electrostatic attractions
    4. disulfide bonds
    • a. Alpha helix – H bonds
    • b. Beta sheet – H bonds
    • c. Protein primary structure – disulfide bonds
    • d. Secondary structure – H bonds
    • e. Supersecondary structure – H bonds
    • f. Tertiary structure - ALL
    • g. Hemoglobin subunits – 1, 2 & 3
  11. In the polypeptide backbone which of the following bonds does not allow freedom of rotation?

    A. Alpha carbon to carbonyl carbon
    B. Amido nitrogen to alpha carbon
    C. Carbonyl carbon to amido nitrogen
    C. Carbonyl carbon to amido nitrogen
  12. Which of the following amino acid side chains would be expected to be found in the interior of a globular protein?

    A. Ala
    B. Ser
    C. Thr
    D. Arg
    E. Gln
    F. Phe
    F. Phe
  13. All of the following will denature proteins except for which one?

    A. Pb2+
    B. Urea
    C. Sodium dodecyl sulfate
    D. 72 C
    E. 5 C
    F. pH 3
    E. 5 C
  14. Two proteins X and B have molecular weights of 51300 Da and 51400 Da, respectively. X has a charge of +3 at pH 6.9 and Y has a charge of -3 at pH 6.9. Both are glucose binding proteins. Which one of the following techniques is the best way to separate their two proteins in their active forms?

    A. Size exclusion chromatography
    B. Cation exchange chromatography
    C. Anion exchange chromatography
    D. Affinity chromatography
    E. SDS PAGE
    • B. Cation exchange chromatography
    • C. Anion exchange chromatography
  15. The active form of the iron in myoglobin is the ___ form.

    A. +1
    B. +2
    C. +3
    D. +4
    B. +2
  16. The iron of the alpha globin of hemoglobin is coordinated with which of the following in the absence of oxygen?

    A. 5 nitrogen atoms of the porphyrin and the distal histidine
    B. 5 nitrogen atoms of the porphyrin and the proximal histidine
    C. 5 nitrogen atoms of the porphyrin, the proximal histidine and the distal histidine
    D. 4 nitrogen atoms of the porphyrin and the distal histidine
    E. 4 nitrogen atoms of the porphyrin and the proximal histidine
    F. 4 nitrogen atoms of the porphyrin, the proximal histidine and the distal histidine
    E. 4 nitrogen atoms of the porphyrin and the proximal histidine
  17. The R state of hemoglobin:

    A. Has a high affinity for oxygen.
    B. Binds preferentially to protons over the T state.
    C. Binds preferentially to carbon dioxide over the T state.
    D. Binds preferentially to BPG over the T state.
    A. Has a high affinity for oxygen.
  18. The conversion of the T state of hemoglobin to the R state is accompanied by the formation of:

    A. New hydrogen bonds in the subunit interfaces
    B. New electrostatic interactions in the subunit interfaces
    C. New hydrophobic interactions in the subunit interfaces
    D. A new binding site for BPG
    E. A new binding site for protons
    F. A new binding site for carbon dioxide.
    • A. New hydrogen bonds in the subunit interfaces
    • B. New electrostatic interactions in the subunit interfaces
    • C. New hydrophobic interactions in the subunit interfaces
  19. Lowering the pH will move the oxygen-binding curve for Hemoglobin to:

    A. the left
    B. the right
    C. that of myoglobin
    B. the right
  20. Carbon monoxide:

    A. Binds to Hb more tightly to Hb than oxygen.
    B. Increases the P50 value of Hb.
    C. Shifts the oxygen-binding curve to a lower max value.
    D. Converts the saturation curve to one that resembles that for myoglobin.
    • A. Binds to Hb more tightly to Hb than oxygen.
    • C. Shifts the oxygen-binding curve to a lower max value.
    • D. Converts the saturation curve to one that resembles that for myoglobin.
  21. How many copies of each type of globin gene are found on one chromosome 16 or 11 of
    a normal person?

    Alpha
    Beta
    Gamma
    Delta
    Epsilon
    Zeta
    • Alpha 2
    • Beta 1
    • Gamma 2
    • Delta 1
    • Epsilon 1
    • Zeta 1
  22. What is the developmental stage for the synthesis of Hb alpha2:gamma2?

    A. Embryonic
    B. Fetal
    C. Adult
    B. Fetal
  23. What is the mutation in Sickle Cell Disease?

    A. Val6Glu
    B. Gly6Val
    C. Val6Gly
    D. Glu6Lys
    E. Glu6Val
    E. Glu6Val
  24. HbH disease is which of the following?

    A. Loss of 2 alpha genes
    B. Loss of 3 alpha genes
    C. Loss of 4 alpha genes
    D. Loss of 2 beta genes
    E. Iron is in the +3 state
    F. Beta-thalassemia
    B. Loss of 3 alpha genes
  25. Cooley’s anemia:

    A. Beta-thalassemia minor
    B. Beta-thalassemia major
    C. HbM
    D. HbE
    E. Heinz bodies
    • B. Beta-thalassemia major
    • E. Heinz bodies
  26. Which electrophoretic profile corresponds to that of a Sickle Cell Disease patient?
    A
  27. Properties of Collagen include:

    A. It is a double stranded coil.
    B. Nearly one third of the amino acids are Gln.
    C. Alpha helix.
    D. Some types form fibers, some form network and some form gels.
    E. Each strand is a right-handed coil.
    F. Devoid of Pro as it is a helix breaker.
    D. Some types form fibers, some form network and some form gels.
  28. Synthesis and maturation of collagen:

    A. Requires ascorbic acid
    B. Occurs in the ECM
    C. Involves hydroxylation of glycine residues
    D. Involves precursor proteins
    E. Does not involve disulfide bonds
    F. Requires the action of collagen peptidases that act inside the Golgi
    G. Involves cross-links between modified lysine side chains
    H. Requires that action of Lys oxidase which is an iron enzyme
    • A. Requires ascorbic acid
    • B. Occurs in the ECM
    • D. Involves precursor proteins
    • G. Involves cross-links between modified lysine side chains
  29. Osteogenesis Imperfecta:

    A. Is “brittle bone” disease.
    B. Is the result of the failure to synthesize elastin.
    C. Is associated with blue sclera
    D. Is easily treated with dietary supplementation with copper.
    E. Is an X-linked disorder.
    • A. Is “brittle bone” disease.
    • C. Is associated with blue sclera
  30. Keratin:

    A. Is a form of vitamin A.
    B. Has mostly alpha-helix as its secondary structure.
    C. Is stretchable.
    D. Contains a double helix.
    • B. Has mostly alpha-helix as its secondary structure.
    • D. Contains a double helix.
  31. Elastin:

    A. Functions as a scaffold upon which fibrillin is deposited.
    B. Is degraded by alpha1 antitrypsin.
    C. Is cross-linked with the amino acid desmosine.
    D. Is produced by neutrophils.
    C. Is cross-linked with the amino acid desmosine.
  32. The major effect of enzymes is to:

    A. Assist the substrate in reaching the transition state.
    B. Transform the transition state to the product
    C. Speed up the forward reaction
    D. Speed up the reverse reaction
    E. All of the above are correct.
    E. All of the above are correct.
  33. Which letter below corresponds to the transition state of the uncatalyzed reaction?

    B
  34. The substrate binding site of chymotrypsin is designed to accommodate which of the following amino acid side chains in it substrate?

    A. Glu
    B. Gly
    C. Ala
    D. Lys
    E. His
    F. Tyr
    F. Tyr
  35. Serine enzymes catalyze hydrolysis reactions using which of the following catalytic mechanisms?

    A. Formation of covalent intermediates
    B. Binding of tetrahedral transition states
    C. Rearranging the
    atoms in the peptide bond of substrates
    D. Deleting the atoms of the peptide bonds of substrates
    • A. Formation of covalent intermediates
    • B. Binding of tetrahedral transition states
  36. Which of the following statements about enzymes is/are true?

    A. Enzymes work at all pH values
    B. The rate of enzyme catalyzed reactions increases with temperature until the enzyme is denatured
    C. Adding more enzyme will increase the rate of the reaction catalyzed by the enzyme.
    D. Enzymes catalyze the reaction at the same rate no matter what the substrate concentration is.
    • B. The rate of enzyme catalyzed reactions increases with temperature until the enzyme is denatured
    • C. Adding more enzyme will increase the rate of the reaction catalyzed by the enzyme.
  37. What is a definition of Km?

    A. It is the same as Vmax.
    B. It is a substrate concentration.
    C. It is the substrate concentration that is equal to Vmax.
    D. It is the equilibrium constant of the reaction.
    B. It is a substrate concentration.
  38. From the numerical value of the point indicated by the red letter on the figure, which one can be used directly to obtain the value of Vmax?
    B
  39. What is the effect of a competitive inhibitor of an enzyme on Vmax and Km?

    A. It lowers Km and V max.
    B. It raises Km and Vmax.
    C. It raises Km and lowers Vmax
    D. It lowers Km and raises Vmax.
    E. It has no effect on Km but lowers Vmax
    F. It raises Km but has no effect on Vmax
    G. It lowers Km but has no effect on Vmax
    F. It raises Km but has no effect on Vmax
  40. @font-face {
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    The plot below shows the effects of increasing
    concentrations of which type of inhibitor on an enzyme – substrate interaction?



    A) Competitive
    B) Non-competitive
    C) Uncompetitive
    D) Irreversible
    A) Competitive
  41. Lead ion (Pb2+) inhibits the enzyme ferrochetalase blocking the formation of heme. What is the type of inhibition by lead ion on this enzyme?

    A) Competitive
    B) Noncompetitive
    C) Uncompetitive
    B) Noncompetitive
  42. Which of the following statements about the
    inhibition of acetylcholine esterase by diisopropylfluorophosphate (DIFP) is/are true?

    A) It is an irreversible inhibitor.
    B) It binds with high affinity because it has a shape that mimics the transition state in the catalysis by acetylcholine esterase
    C) It binds to the His side chain of His enzymes.
    D) It modifies sulfhydryl groups irreversibly.
    • A) It is an irreversible inhibitor.
    • B) It binds with high affinity because it has a shape that mimics
    • the transition state in the catalysis by acetylcholine esterase
  43. A zymogen is an inactive enzyme precursor:

    A) that may be activated by metal ions.
    B) that may be activated by proteolysis.
    C) that may be activated by adding more substrate.
    D) that may be activated by adding an allosteric activator.
    E) that is also known as a proenzyme.
    • B) that may be activated by proteolysis.
    • E) that is also known as a proenzyme.
  44. Allosteric regulation of enzymes:

    A) May involve positive effectors.
    B) May involve negative effectors.
    C) May involve a heterotrophic effector.
    D) May involve a change in Vmax but not a change in Km
    • A) May involve positive effectors.
    • B) May involve negative effectors.
    • C) May involve a heterotrophic effector.
  45. Watson and Crick base pairing rules stipulate that in double-stranded deoxyribonucleotides, the base A pairs with:

    A. A
    B. C
    C. G
    D. T
    E. U
    D. T
  46. The structure of DNA:

    A. An alpha helix
    B. A coil of two identical strands
    C. A coil of two complimentary strands
    D. A coil of two strands that are not related
    to each other regarding the base sequence
    C. A coil of two complimentary strands
  47. Regarding the DNA Double Helix:

    A. The strands are parallel.
    B. The strands are anti-parallel.
    C. The strands are anti-complimentary.
    D. The number of A = the number of T.
    E. The number of C = the number of G.
    • B. The strands are anti-parallel.
    • D. The number of A = the number of T.
    • E. The number of C = the number of G.
  48. Regarding the structure of DNA:

    A. There is only one groove.
    B. The bases lie in a plane that is
    perpendicular to the axis of the coil.
    C. The most common form of DNA in cells type “A” DNA.
    D. The AT pairs have 3 hydrogen bonds while the CG pairs have 2 hydrogen bonds
    • B. The bases lie in a plane that is
    • perpendicular to the axis of the coil.
  49. The nucleosome contains all of the histones EXCEPT for which one?

    A. H1
    B. H2A
    C. H2B
    D. H3
    E. H4
    A. H1
  50. What property of histones makes them highly likely to associate with DNA?

    A. They have DNA binding sites.
    B. The are negatively charged
    C. They are positively charged.
    D. They contain DNA that hybridizes with DNA
    C. They are positively charged.
  51. The protein complex that associates with the centromere and attaches to the microtubules during mitosis is known as:

    A. Kinetochore
    B. Centromere protein
    C. Tau protein
    D. Constriction protein
    A. Kinetochore
  52. Pseudogenes:

    A. Are genes that generate an inactive protein.
    B. Are genes that are defective and may have no promoter.
    C. Are genes that may have been made by gene duplication but subsequently were mutated to an inactive form.
    D. Are genes that have only introns and no
    exons.
    • B. Are genes that are defective and may have no promoter.
    • C. Are genes that may have been made by gene duplication but subsequently were mutated to an inactive form.
  53. Ribosomal RNA genes:

    A. Found on the very short p arm of
    chromosomes 13, 14, 15 ,21 and 22.
    B. Are found in about 200 copies per genome.
    C. Encode RNA that is used in protein
    synthesis
    D. All of the above are correct.
    D. All of the above are correct.
  54. Transposons:

    A. Are made of RNA.
    B. Can move from one location is DNA to
    another.
    C. Make up only 1 % of the human genome
    D. Protect DNA from mutation.
    • B. Can move from one location is DNA to
    • another.
  55. Regarding the replication of the two strands of DNA:

    A. Are replicated both in the 3’ to 5’ direction.
    B. Are replicated both in the 5’ to 3’ direction.
    C. The leading strand is replicated in the 5’ direction and the lagging strand is replicated in the 3’ direction.
    D. Only the template strand is replicated; the coding strand is not replicated.
    B. Are replicated both in the 5’ to 3’ direction.
  56. Which of the following enzymes unwinds the DNA double helix during replication of prokaryote DNA?

    A. DNA polymerase I
    B. DNA polymerase III
    C. Helicase
    D. Topoisomerase
    E. DNA ligase
    F. Primase
    C. Helicase
  57. Which of the following enzymes adds RNA to the end of the leading strand during replication of prokaryotic DNA?

    A. DNA polymerase I
    B. DNA polymerase III
    C. Helicase
    D. Topoisomerase
    E. DNA ligase
    F. Primase
    F. Primase
  58. Which DNA replication enzyme completes DNA synthesis?

    A. DNA polymerase I
    B. DNA polymerase III
    C. Helicase
    D. Topoisomerase
    E. DNA ligase
    F. Primase
    E. DNA ligase
  59. The location where DNA synthesis occurs is known as:

    A. The DNA replicant.
    B. The replication site.
    C. The replication fork.
    D. The DNA synthesis spot.
    D. The DNA synthesis spot.
  60. Single stranded DNA binding proteins are important to DNA replication because they:

    A. Bind to DNA after each strand is synthesized.
    B. Bind to the ends of the double helix to prevent exonuclease digestion of the 5’ overhangs.
    C. Cause the unwinding of the DNA double helix.
    D. Have both 3’ and 5’ exonuclease activity.
    E. Hold the unwound DNA open.
    E. Hold the unwound DNA open.
  61. Which DNA polymerase is responsible for the synthesis of most of the leading strand?

    A. Polymerase I
    B. Polymerase II
    C. Polymerase III
    D. Primase
    C. Polymerase III
  62. How is DNA replication in eukaryotes different from prokaryotes?

    A. Prokaryote DNA replication produces Okazaki fragments but eukaryote DNA
    replication does not.
    B. Eukaryote DNA replication produces Okazaki fragments but prokaryote DNA replication does not.
    C. Prokaryote DNA replication requires an RNA primer but eukaryote DNA replication requires a DNA primer
    D. Prokaryote DNA replication requires an RNA primer but eukaryote DNA replication requires a DNA primer
    E. Eukaryote DNA replication requires an RNA primer but prokaryote DNA replication requires a DNA primer
    F. Prokaryote DNA replication is initiated from one site whereas eukaryote DNA replication is initiated from many sites.
    F. Prokaryote DNA replication is initiated from one site whereas eukaryote DNA replication is initiated from many sites.
  63. Telomerase action:

    A. Is required to lengthen the template strand so as to allow completion of replication of the lagging strand.
    B. Adds DNA to the 3’ ends of each chromosomal DNA.
    C. Prevents shortening of DNA during each round of synthesis.
    D. Is required by cells that divide indefinitely like tumor cells
    E. All of the above
    E. All of the above
  64. Which type of RNA is found in cells in the highest amounts?

    A. rRNA
    B. mRNA
    C. tRNA
    D. snRNA
    E. Primer RNA
    A. rRNA
  65. Which type of RNA carries information about the sequence of amino acids in a protein?

    A. rRNA
    B. mRNA
    C. tRNA
    D. snRNA
    E. Primer RNA
    B. mRNA
  66. Which type of RNA is associated with amino acids during translation?

    A. rRNA
    B. mRNA
    C. tRNA
    D. snRNA
    E. Primer RNA
    C. tRNA
  67. Which of the following are features of mRNA?

    A. mRNA is capped on its 5’ end with 7-methylguanosine.
    B. mRNA has poly U attached to its 3’ end.
    C. mRNA is found in the cloverleaf structure.
    D. mRNA is made up of two strands where tRNA and ribosomal RNA are single
    stranded.
    A. mRNA is capped on its 5’ end with 7-methylguanosine.
  68. The amino acid is attached to tRNA:

    A. At the 5’ end.
    B. At the 3’ end.
    C. To the acceptor arm by way of an ester linkage to the 2’ OH group of ribose.
    D. To the anti-codon arm.
    B. At the 3’ end.
  69. The codon for the amino acid Phe is UUC. What is the base sequence of the anti-codon found on tRNA Phe?

    A. AAG
    B. GAA
    C. CUU
    D. UUC
    B. GAA
  70. E. coli ribosomes:

    A. Are larger than those in a snake.
    B. Consist of 30S and 50S subunits.
    C. Are entirely RNA and contain no proteins.
    D. Are encoded by DNA found in chromosomes 13, 14, 15, 21 and 22
    B. Consist of 30S and 50S subunits.
  71. Transcription in prokaryotes by RNA polymerase

    A. Requires the searching of the template strand of DNA for promotersequences by the rho factor.
    B. Often forms a polycistronic mRNA.
    C. Requires three different polymerases to transcribe all the various types of RNA.
    D. Does not require topoisomerase or helicase but eukaryotic transcription does.
    B. Often forms a polycistronic mRNA.
  72. Regarding the processing of hnRNA in eukaryotes:

    A. Capping of the polynucleotide occurs in the nucleus.
    B. snRNA is required for the removal of introns.
    C. Poly A tailing occurs in the cytoplasm
    D. Makes the RNA more stable against ribonuclease destruction of the product.
    • A. Capping of the polynucleotide occurs in the nucleus.
    • B. snRNA is required for the removal of introns.
    • D. Makes the RNA more stable against ribonuclease destruction of the product.
  73. Transcription in prokaryotes:

    A. Is 3’ to 5’.
    B. Reads, i.e., replicates, the coding strand.
    C. Uses the sigma factor to find the promoter (initiator sequences).
    D. Requires a primer like DNA synthesis.
    C. Uses the sigma factor to find the promoter (initiator sequences).
  74. What are the energy requirements in terms of phosphate linkages from GTP for the following steps in protein synthesis elongation?

    __ for binding of the aminoacyl tRNA to the A site
    __ for formation of the peptide bond
    __ for translocation.

    A. 1, 2, 1
    B. 1, 0, 1
    C. 2, 0, 2
    D. 0, 1, 0
    E. 1, 1, 1
    B. 1, 0, 1
  75. Which of the following statements about the genetic code is correct?

    A. A codon may encode for two amino acids.
    B. A tRNA may bind to two different amino acids.
    C. The Wobble position of a codon is the first position, the one on the 5’ end.
    D. The genetic code is degenerate, that is, there are sometimes several codons for one amino acid.
    E. There are only 20 codons that encode for the incorporation of an amino
    acid into a protein.
    D. The genetic code is degenerate, that is, there are sometimes several codons for one amino acid.
  76. How many high energy bonds must be hydrolyzed to synthesize each peptide bond starting with free amino acids and other factors as needed?

    A. 0
    B. 1
    C. 2
    D. 3
    E. 4
    F. 5
    E. 4
  77. Shine-Dalgarno homology sequence is present on which ribosomal subunit?

    A. 30 S
    B. 40 S
    C. 50 S
    D. 60 S
    A. 30 S
  78. Which of the following is characteristic of eukaryote protein synthesis, but NOT prokaryote protein synthesis?

    A. Shine-Dalgarno sequence.
    B. mRNA cap.
    C. The mRNA is read 5’ to 3’.
    D. Synthesis is N-terminal to C-terminal.
    E. Termination by releasing factors.
    F. Formyl-Met-tRNA
    B. mRNA cap.
  79. Protein factor involved in prokaryote protein synthesis: its role.

    A. EF-Tu: binding of aminoacyl tRNA to the A site
    B. EF-G: translocation of ribosomes and mRNA.
    C. IEF-3: initiation of protein synthesis
    D. Rho factor: termination of protein synthesis
    • A. EF-Tu: binding of aminoacyl tRNA to the A site
    • B. EF-G: translocation of ribosomes and mRNA.
    • C. IEF-3: initiation of protein synthesis
  80. The first codon that encodes for an amino acid in mRNA is:

    A. UGA
    B. UAA
    C. AUG
    D. ACC
    E. TATA
    C. AUG
  81. An mRNA was isolated from a rabbit in your research laboratory and was determined
    to have the following sequence. Translate this mRNA using the codon table attached.

    A. Glu Pro Met Ala Phe
    B. Asn Leu Trp Pro Ser Asn Ile
    C. Met Ala Phe
    D. Met Ala Phe Trp His Leu Lys Lys Lys Lys Lys
    C. Met Ala Phe
  82. A DNA transversion is:

    A. The substitution of an adenine for guanine
    B. The substitution of a uracil for a cytosine
    C. The substitution of a guanine for a cytosine
    D. The substitution of a uracil for an adenine
    • C. The substitution of a guanine for a cytosine
    • D. The substitution of a uracil for an adenine
  83. The mutation that leads to the substitution of an Ala for a Glu is described as a:

    A. Consensus substitution
    B. Missense mutation
    C. Nonsense mutation
    D. Silent mutation
    E. Conservative mutation
    B. Missense mutation
  84. All of the following are conservative substitutions EXCEPT for:

    A. Phe for Leu
    B. His for Gln
    C. Arg for Leu
    D. Leu for Trp
    E. Lys for Arg
    C. Arg for Leu
  85. @font-face {
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    A nonsense mutation is:

    A. One that does not make sense
    B. One that requires a two base change
    C. One that forms a stop codon
    D. One that forms an initiation codon
    C. One that forms a stop codon
  86. A frame shift mutation:

    A. Is created upon the addition of 2 bases (i.e., nucleotides) to the mRNA.
    B. Is created by the deletion of 4 bases from the mRNA.
    C. Is often associated with the premature termination of protein synthesis.
    D. Usually shortens the polypeptide length.
    E. Is associated with the addition of a garbled amino acid sequence at and beyond the point of the mutation
    F. All of the above
    F. All of the above
  87. How many termination codons are there in the normal reading frame of an mRNA?

    A. 0
    B. 1
    C. 2
    D. 3
    E. 4
    B. 1
  88. A patient with non-polyposis colon cancer would be expected to have a mutation in
    which of the following?

    A. An enzyme required for the
    recognition of mis-matched bases in the double stranded DNA.
    B. Factors required for the re-joining of broken double stranded DNA.
    C. Uracil DNA N-glycosylase
    D. DNA ligase
    • A. An enzyme required for the
    • recognition of mis-matched bases in the double stranded DNA.
  89. The repair of a mutation that caused the dimerization of adjacent thymine bases
    would require all of the following enzymes EXCEPT for which one?

    A. Uracil DNA N-glycosylase
    B. DNA ligase
    C. DNA polymerase
    D. Excision endonuclease (excinuclease)
    A. Uracil DNA N-glycosylase
  90. Xeroderma pigmentosum is caused by a defect in which of the following enzymes?

    A. Excision endonuclease (excinuclease)
    B. DNA ligase
    C. DNA pol beta
    D. Enzyme required for repair of double stranded DNA breakage
    A. Excision endonuclease (excinuclease)
  91. Failure to repair double-strand DNA breaks is a cause of:

    A. Hereditary non-polyposis colon cancer
    B. Ataxia-telangiectasia.
    C. Xeroderma pigmentosum
    D. Patau syndrome
    B. Ataxia-telangiectasia.
  92. A patient shows neurodegeneration in the form of movement disorders and has visible enlargement of capillaries in the sclera of the eye. This patient is sensitive to radiation from X-ray machines and has poor immune responses. This patient has:

    A. Edward syndrome
    B. Hereditary non-polyposis colon cancer
    C. Xeroderma pigmentosum
    D. Ataxia-telangiectasia.
    D. Ataxia-telangiectasia.
  93. Most restriction endonucleases produce “sticky” ends. What are “sticky” ends?

    A. They are ends with butter and honey on them.
    B. They are 3’ overhangs which can form base pairs with other ends with
    complimentary sequences.
    C. They are 5’ overhangs which can form base pairs with other ends with complimentary sequences.
    D. The 5’ end of every dsDNA.
    E. The 3’ end of every dsDNA.
    • B. They are 3’ overhangs which can form base pairs with other ends with
    • complimentary sequences.
    • C. They are 5’ overhangs which can form base pairs with other ends with complimentary sequences.
  94. A DNA molecule of interest had the following sequence. ACTTCTAGGG. Which of the following probes could be used to detect this molecule on paper following blotting?

    A. ACTTCTAGGG
    B. GGGATCTTCA
    C. TGAAGATCCC
    D. CCCTAGAAGT
    D. CCCTAGAAGT
  95. In the PCR reaction, there are three different temperatures used: 94 C, 60 C and 72 C. What part of the PCR reaction process is occurring at 72 C?

    A. Denaturation of the dsDNA
    B. Annealing of the primers
    C. Enzymatic synthesis of DNA
    D. Hydrolysis of the strands
    C. Enzymatic synthesis of DNA
  96. Synthesis of cDNA uses which all the following components EXCEPT for which one?

    A. Reverse transcriptase
    B. mRNA
    C. RNA-dependent DNA polymerase
    D. Initiation factor IF3
    D. Initiation factor IF3
  97. If a plasmid is to be useful for amplification of DNA, it must have all of the following EXCEPT for which one?

    A. An origin of replication
    B. And antibiotic resistance gene
    C. A stop codon
    D. A restriction site
    C. A stop codon
  98. A fragment of DNA is cloned into a plasmid and then isolated for sequencing. The gel pattern shown in this diagram is obtained. What Is the sequence of the DNA strand?

    A. GCTAGCA
    B. ACGATCG
    C. TGCTAGC
    D. CGATCGT
    C. TGCTAGC
  99. To perform a Southern blot one needs all of the following EXCEPT for which one?

    A. mRNA
    B. A DNA digest containing the DNA of interest
    C. Agarose gel
    D. DNA probe
    A. mRNA
  100. A DNA micro array:

    A. Can be made for thousands of different genes on a single plate.
    B. Is used to determine which genes are expressed in a cell type of tissue
    C. Can be used to determine if a cancer gene has been activated
    D. Can be used to determine if a gene is not expressed in a cell
    E. All of the above
    E. All of the above
  101. A family of Mother, Father and 4 children were see by you in your Genetics clinic. The parents have just been made aware that a rare autosomal recessive genetic disease runs in the family that cannot be detected clinically until age 10 or older. They want to know if they are carriers and if any of their children will be afflicted. You remember from your Genetics course that this disease is caused by a mutation in the stop codon that destroys activity and creates a new restriction site. An RFLP was determined using a restriction endonuclease that cleaves the DNA at the arrows to see what genotypes the four children were. Which child (children) is (are) normal and not a carrier of the mutation?

    A. 1
    B. 2
    C. 3 and 4
    A. 1
  102. Gene Expression is tightly regulated. The most important site of regulation is:

    A. Transcription initiation
    B. Transcription termination
    C. mRNA processing
    D. Translation
    E. Transcription elongation
    A. Transcription initiation
  103. Which of the following is a protein?

    A. Promoter
    B. Enhancer
    C. Transcription factor
    D. Steroid receptor response element
    C. Transcription factor
  104. Which of the following determines the strand to be used as the template in transcription?

    A. The strand with the TATA sequence.
    B. The strand with the CAAT sequence.
    C. The strand with the enhancer sequence.
    D. The strand with an AUG and a stop codon.
    E. The strand with the ribosomal binding
    site.
    D. The strand with an AUG and a stop codon.
  105. All or the following are commonly found in DNA binding proteins EXCEPT for which one?

    A. Helix-turn-helix
    B. Zinc finger
    C. Leucine zipper
    D. Sigma peptide
    E. Helix-loop-helix
    D. Sigma peptide
  106. You have isolated a functional protein from a
    tissue where it had never been studied before. When isolated from this tissue, it was found to have 16 different amino acids added to its N-terminal sequence. Inspection of the human genome sequences reveals that there was only one copy of this gene in the entire genome. It is found on chromosome 3. What is the likely explanation for finding these extra amino acids in the protein?

    A. This protein has an intron splice site
    mutation.
    B. This protein has an alternative promoter
    on the 5’ side of the usual one.
    C. This protein was alternatively spliced.
    D. The mRNA for this protein was processed in the cytosol where extra amino acids are added to the N-terminus of proteins.
    E. The mRNA for this protein has an iron
    response element that changed its amino acid sequence.
    • B. This protein has an alternative promoter
    • on the 5’ side of the usual one.
  107. Transferrin is produced when:

    A. The IRE-BP binds to iron.
    B. The ferritin gene is silenced by excess
    iron.
    C. Ribosomes bind to the IRE-BP stimulating translation of the transferrin mRNA.
    D. There is insufficient iron in the cell.
    D. There is insufficient iron in the cell.
  108. Which of the following sequences of events
    account for the ability of glucagon to stimulate expression of certain genes?

    A. Glucagon stimulates the production of
    cAMP, activating protein kinase A to phosphorylate ribosomal proteins, stimulating translation.
    B. Glucagon reduces the level of cAMP in
    cells, activating protein kinase A, leading to phosphorylation of certain transcription factors.
    C. Glucagon increases the level of cAMP,
    activating protein kinase A, which phosphorylates the cAMP response element
    binding protein (CREBP), which leads to its binding to DNA, altering transcription.
    D. Glucagon activates certain phosphatases,
    which remove phosphate groups on the cAMP response element binding protein, which leads to the binding of CREB to DNA.
    • C. Glucagon increases the level of cAMP,
    • activating protein kinase A, which phosphorylates the cAMP response element
    • binding protein (CREBP), which leads to its binding to DNA, altering transcription.
  109. It has been shown that lactose (in the form of
    allolactose) stimulates the production of enzymes required for the uptake and
    hydrolysis of lactose by E. coli. How does it do this?

    A. Lactose binds to the DNA at the transcription start site causing RNA polymerase to initiate transcription of the lac operon.
    B. Lactose binds the repressor causing it to
    bind to the operator recruiting RNA polymerase to initiate transcription.
    C. Lactose binds to the repressor protein
    causing it to release from the operator site, allowing transcription.
    D. Lactose binds to a lactose response
    element stimulating mRNA synthesis.
    • C. Lactose binds to the repressor protein
    • causing it to release from the operator site, allowing transcription.
  110. The trp operon of E. coli regulates the amount of tryptophan produced in these cells under various nutrient conditions. Which of the following statements best describes the role of tryptophan in this process?

    A. Tryptophan is an operator.
    B. Tryptophan is an inducer.
    C. Tryptophan is a repressor.
    D. Tryptophan is a co-repressor.
    D. Tryptophan is a co-repressor.
  111. The following drawing represents a chromosome stained with Giemsa and was taken from a patient with an autosomal dominant mutation in 4p11.3. Which arrow most closely points to this region?



    A.
    B.
    C.
    D.
    E.
    B.
  112. Which staining methodology would be used to stain the chromosomal region marked with the letter C?



    A. G banding
    B. Q banding
    C. R banding
    D. C banding
    E. Spectral Karyotyping (SKY)
    D. C banding
  113. A 13-week fetus was spontaneously aborted and analyzed for chromosomal defects by spectral karyotyping. The following photograph and karyotype reveals which of the following chromosomal
    disorders?



    A. Robertsonian translocation
    B. Balanced translocation
    C. Trisomy
    D. Monosomy
    E. Isochromosome
    C. Trisomy
  114. The chromosome on the left is normal and has been modified to the structure shown on the right. What is the description of this change in structure?



    A. Balanced translocation
    B. Isochromosome
    C. Paracentric inversion
    D. Pericentric inversion
    E. Robertsonian translocation
    D. Pericentric inversion
  115. What is the chance that a couple will have a male child with Sickle Cell disease if both parents are heterozygous for the Glu6Val mutation?

    A. 0 %
    B. 12.5 %
    C. 25 %
    D. 37.5 %
    E. 50 %
    F. 62.5 %
    G. 75 %
    H. 87.5 %
    I. 100 %
    B. 12.5 %
  116. What is the risk to the child for the inheritance of alpha1-antitrypsin deficiency syndrome if the mother is affected and the father has a normal genotype with no alpha1-antitrypsin mutations?

    A. 0 %
    B. 25 %
    C. 50 %
    D. 75 %
    E. 100 %
    A. 0 %
  117. A couple comes to your clinic for genetic counseling since the prospective mother had a paternal uncle who had Duchenne muscular dystrophy, an X-linked recessive disorder. You test her for all of the common DMD alleles and find that she is an unaffected carrier. What % of her future sons is likely to have DMD?

    A. 0 %
    B. 25 %
    C. 50 %
    D. 75 %
    E. 100 %
    • C. 50 %
  118. @font-face {
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    Your 14-year old male patient has been shown to carry a deletion of one copy of region 15q11-13 on his two chromosomes 15. This region of chromosome is imprinted. The child is mentally retarded and suffers from significant obesity. The child’s father and mother were subjected to FISH analysis for the presence of gene SNRPN. Which FISH, A or B or Neither, was obtained from the father?

    • B. The patient has Prader-Willi Syndrome. This disorder is caused by deletion of
    • paternal genes in the region 15q11-13, evident in B. Because of imprinting in the maternal chromosome 15, some genes are not expressed from the maternal chromosome even though they are present.
  119. A certain cell type in the ovary secretes IGF-1, which in turn binds to cell surface receptors on the same cell that secreted the growth factor. Under these conditions IGF-1 acts as a/an:

    A. Autocrine factor
    B. Paracrine factor
    C. Endocrine factor
    D. Steroid receptor hormone factor
    A. Autocrine factor
  120. Classify the following hormone receptors as to whether they are (S) cell surface receptors or (N) cytoplasmic/nuclear receptors.

    1. Insulin receptor S or N
    2. Thyroid hormone receptor S or N
    3. Estradiol receptor S or N
    S, S, N
  121. Which type of hormones act primarily through transcription factors?

    A. Cell surface receptors
    B. Mitochondrial receptors
    C. Lysosomal receptors
    D. Cytoplasmic/nuclear
    D. Cytoplasmic/nuclear
  122. The receptors of growth factors like epidermal growth factor (EGF), fibroblast growth factor (FGF), platelet derived growth factor (PDGF) and insulin all have receptors with which of the following types of enzyme activities?

    A. Serine kinase
    B. Tyrosine kinase
    C. Threonine kinase
    D. Asparagine kinase
    B. Tyrosine kinase
  123. The insulin receptor acts through which of the following mechanisms?

    A. Activation of Gsalpha
    B. cAMP as its second messenger
    C. cGMP as its second messenger
    D. Autophosphorylation of insulin on tyrosine
    E. Autophosphorylation of the receptor on tyrosine
    E. Autophosphorylation of the receptor on tyrosine
  124. The binding of glucagon to its receptor stimulates which of the following actions?

    A. Autophosphorylation of glucagon on tyrosine
    B. Autophosphorylation of the glucagon receptor on tyrosine
    C. Phosphorylation of adenylate cyclase on serine
    D. Exchange of GTP in place of a GDP on Gsalpha
    D. Exchange of GTP in place of a GDP on Gsalpha
  125. cAMP activates:

    A. PKA
    B. PKB
    C. PKC
    D. Tyrosine kinase
    A. PKA
  126. Phosphodiesterase (PDE) activity regulates the amount of cAMP in cells of many tissues. Which of the following would be expected to raise cAMP levels in cells by inhibiting PDE
    activity?

    A. Caffeine
    B. High blood sugar
    C. Gsi with bound GTP
    D. All of the above
    A. Caffeine
  127. Which of the following would be expected to cause a permanent activation of Gsalpha by ADP ribosylation?

    A. Glucagon
    B. Steroid hormones
    C. Insulin
    D. Cholera toxin
    E. Blowfish toxin
    D. Cholera toxin
  128. Which G protein activates phospholipase C (PLC) when bound to GTP?

    A. Gsalpha
    B. Gq
    C. Gsi
    D. Galpha ,beta ,gamma
    B. Gq
  129. What are the products of PLC action on phosphatidyl inositol 4,5-bisphosphate?

    A. DAG
    B. TAG
    C. IP3 (inositol trisphosphate)
    D. PLC does not act on inositol 4,5-bisphosphate
    • A. DAG
    • C. IP3 (inositol trisphosphate)
  130. Calcium release from storage sites requires the presence of:

    A. DAG
    B. TAG
    C. IP3 (inositol trisphosphate)
    D. All of the above
    C. IP3 (inositol trisphosphate)
  131. Achondroplasia is due to a mutation in:

    A. FGF that makes it always active
    B. FGFR that makes it always active
    C. FGF that makes it always inactive
    D. FGFR that makes it always
    inactive
    B. FGFR that makes it always active

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