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BIOCHEMISTRY, CELL AND MOLECULAR BIOLOGY TESTTime—170 minutes

180 Questions

Directions: Each of the questions or incomplete statements below is followed by five suggested answers or completions. Select the one that is best in each case and then completely fill in the corresponding space on the answer sheet.

1. Regulation of metabolic pathways includes all of the following except:a. Regulation of key enzymes in a pathway.b. Control transcription and translation to

regulate enzyme amounts.c. Tissue-specific enzymes and receptors.d. Reciprocal synthetic and degradative

pathways utilize the same set of enzymes.e. Compartmentation of reciprocal synthetic

and degradative pathways.

2. Which of the following statements concerning cell adhesion complexes is INCORRECT?a. Tight junctions are a type of

communicating junction.b. Adherens junctions are a type of

anchoring junction.c. Selectins form anchoring junctions.d. Claudins are a component of tight

junctions.e. Connexons are a component of gap

junctions.

3. Which of the following statements concerning homeotic (Hox) genes is INCORRECT?a. A Hox gene taken from one organism can

function in another organism.b. The order of Hox gene expression along

the embryo matches the order of Hox genes on the chromosome.

c. Mutations in Hox genes can create flies with legs where their antennae should be.

d. Hox genes encode cell surface receptors.e. Antennapedia is a Hox gene.

4. Meiosis can occura. in all organismsb. only when an organism is diploidc. only in multicellular organismsd. only in haploid organismse. only in single-celled organisms

5. At the isoelectric pH of a tetrapeptide: a. the amino and carboxyl termini are not

charged. b. two internal amino acids of the

tetrapeptide cannot have ionizable R groups.

c. the total net charge is zero. d. there are four ionic charges. e. only the amino and carboxyl termini

contribute charge.

6. In the diagram below, the plane drawn behind

the peptide bond indicates the:

a. plane of rotation around the Cα—N bond.

b. absence of rotation around the C—N bond because of its partial double bond character.

c. region of steric hindrance determined by the large C¬O group.

d. theoretical space between –180° and +180° that can be occupied by the and angles in the peptide bond.

e. region of the peptide bond that contributes to a Ramachandran plot.

1Move on to the next page

7. Which of the following situations would result in an increase in ketone body synthesis?a. High insulin/glucagon ratiob. High citrate levels in the cytosolc. High levels of fructose-2,6-bisphosphated. Low oxaloacetate levels in the

mitochondriae. Low acetyl CoA levels in the mitochondria

8. Which of the following statements concerning tumor suppressor genes is most accurate?a. In a normal individual, mutation of one

copy of a tumor suppressor gene leads to cancer.

b. In a normal individual, the development of cancer requires mutation of one copy of a tumor suppressor gene in one cell plus the mutation of the other copy of the gene in another cell.

c. In a normal individual, the development of cancer requires mutation of one copy of a tumour suppressor gene plus the mutation of the other copy of the gene in the same cell.

d. In a normal individual, the development of cancer requires mutation of one copy of a tumor suppressor gene in one cell plus the mutation of the same copy of the gene in another cell.

e. Mutations in tumor suppressor genes are not passed onto the offspring because the individual dies.

9. Given the following reactions:

What is the ΔGo

’ value for the reaction: FADH2+½ O2FAD +H2O

(ΔGo

’ = -nFΔEo’, where F = faraday’s constant=23

kcal/volt mole e-)

a. +46 kcal/mol b. -46 kcal/mol c. +23 kcal/mol d. -23 kcal/mol e. -11.5 kcal/mol

10. The pyruvate dehydrogenase complex is INCORRECTLY described by which of the following? a. Produces CO2, NADH and acetyl

Coenzyme A b. Is phosphorylated in the presence of

insulin c. Requires thiamine pyrophosphate to carry

carbons d. Can be directly inhibited by NADH and

Acetyl Coenzyme A e. Is a target for arsenic poisoning

11. In 1928, Griffith injected S (smooth) bacteria into mice, and the mice died. When he injected living R (rough) bacteria into mice, the mice lived. When he injected heat-killed smooth bacteria into mice, the mice lived. What was the result when he mixed heat-killed S bacteria with live R bacteria and injected this mixture into mice?a. a. the mice livedb. b. the mice died indicating that heat-killed

S bacteria came back to lifec. c. the mice lived, and living S bacteria

could be obtained from the tissues of living mice

d. d. the mice died, indicating that DNA replicated semi-conservatively

e. e. the mice died, and living S cells could be isolated from the tissues of the dead mice

12. The regulation of cholesterol synthesis involves all of the following EXCEPT:a. glucagon activates HMG-CoA reductaseb. cholesterol inhibits the synthesis of HMG-

CoA reductasec. cholesterol increases the degradation of

HMG-CoA reductased. the dephosphorylated form of HMG-CoA

reductase is activee. cholesterol inhibits the synthesis of the

LDL receptor

13. At the end of meiosis I, each chromosome consist ofa. a homologous chromosome pairb. four copies of a DNA moleculec. one copy of a DNA moleculed. two chromatidse. a pair of polar microtubules


14. Which of the molecules shown below can be made directly from pyruvate?

a. Molecules 1 and 4b. Molecules 2 and 3c. Molecules 1, 2, and 4d. Molecules 1, 3, and 4e. Molecules 1, 2, 3, and 4

15. A patient is taking a drug that must be activated by cytochrome p450 enzymes to be fully efficacious. A mutation that inactivates which of the following enzymes would most directly affect the patient’s ability to respond to this medication?a. A. pyruvate carboxylaseb. B. glucose 6-phosphate dehydrogenasec. C. pyruvate kinased. D. malate dehydrogenasee. E. citrate synthase

16. A mutation in the lac operator sequence prevents the lac repressor from binding. What would you expect to see in bacteria harbouring this mutation?a. The bacteria would have difficulty growing

in media containing only lactose.b. In the presence of glucose and lactose, the

polycistronic message for the lac operon would accumulate to its maximum level.

c. The catabolite activator protein would no longer be able to bind.

d. cAMP levels would be constitutively high.e. When both glucose and lactose are

absent, lac permease activity would be higher in the mutant than in normal bacteria.

17. Individual cell migration is most accurately described by which of the following sequence of events?a. (1) Actin polymerization extends from

focal contacts in the direction of migration; (2) New focal contacts are made and the treadmilling actin network engages them to continue the cell extension; (3) Actin depolymerization at the minus end of the treadmilling network detaches the cell from focal contacts at the rear.

b. (1) Actin polymerization extends from focal contacts in the direction of migration; (2) New focal contacts are made and the treadmilling actin network engages them to continue the cell extension; (3) Myosin II contraction detaches the cell from focal contacts at the rear.

c. (1) Actin polymerization extends the cell forward in the direction of migration; (2) Focal contacts are disassembled at the front of the cell to allow it to move over the substratum (3) Myosin II contraction also detaches the cell from focal contacts at the rear.

d. (1) Actin polymerization extends the cell forward in the direction of migration; (2) Focal contacts are disassembled at the front of the cell to allow it to move over the substratum; (3) Actin depolymerization at the minus end of the treadmilling network also detaches the cell from focal contacts at the rear.

e. (1) Individual actin filaments are stabilized by actin binding proteins; (2) Myosin II thick filaments move the actin filament past one another to extend the actin filament system forward; (3) As the actin filaments slide forward they engage focal contacts to pull the rest of the cell forward.


18. Which of the following statements do NOT account for the differences in complexity between eukaryotic transcriptional regulation and bacterial transcriptional regulation?

i. Eukaryotic DNA is packaged into chromatin.ii. Eukaryotic RNA Polymerase II cannot activate transcription on its own.iii. Eukaryotic Shine-Dalgarno sequences generate complex patterns of transcriptional regulation.iv. Eukaryotic gene regulatory proteins act at a distance.v. Eukaryotic gene regulatory proteins are not regulated by ligand binding.

a. i, ii, iiib. ii, ivc. iii, vd. i, ii, ive. ii

19. In an experiment that attempts to identify origins of replication in yeast, randomly selected DNA fragments are introduced into a plasmid that has a selectable marker such as the HIS gene (histidine). Yeast that have plasmids with various DNA fragments introduced are then plated on a selective medium (i.e. without histidine). What would be expected in these experiments?a. Yeast cells that have plasmids with DNA

fragments without putative origins of replication should grow on media without histidine.

b. The strain of yeast used for these experiments should be able to grow in the absence of histidine.

c. In order to replicate, the plasmids used for these experiments do not need a DNA fragment containing an origin of replication.

d. Yeast cells that have integrated the plasmid into their chromosome will be able to grow on media without histidine, regardless of whether they have a putative origin of replication or not.

e. Yeast cells must be plated on medium with histidine to determine if they have plasmids with DNA fragments containing putative origins of replication.

20. Which of the following oligonucleotides will dissociate at the lowest temperature?a. ACGTACGTACGT

TGCATGCATGCAb. TGCGACGCTGAG

ACGCTGCGACTCc. ACTGCTGGACCT

TGACGACCTGGAd. TGCATGCATGCA

ACGTACGTACGTe. AATGCTTACTGTA

TTACGAATGACAT

21. In the presence of high glucagon levels, what is the status of glycogen phosphorylase? a. Is phosphorylated, active, and sensitive to

glucose 6-phosphate levels b. Is unphosphorylated, active, and sensitive

to glucose 6-phosphate levels c. Is phosphorylated, inactive, and sensitive

to glucose 6-phosphate d. Is phosphorylated, active, and sensitive to

glucose levels e. Is unphosphorylated, inactive, and

sensitive to glucose levels

22. The cadherin-cadherin binding mechanism is most accurately described by which of the following sequence of events?a. (1) cis-dimerization promotes receptor

straightening; (2) calcium promotes heterophilic, trans-interactions between the receptors; (3) the receptors interact with actin.

b. (1) cis-dimerization promotes receptor straightening; (2) calcium promotes homophilic, trans-interactions between the receptors; (3) the receptors form large clusters.

c. (1) Calcium promotes receptor straightening; (2) cis-dimerization promotes homophilic, trans-interactions between the receptors; (3) the receptors form large clusters.

d. (1) Calcium promotes receptor straightening; (2) cis-dimerization promotes heterophilic, trans-interactions between the receptors; (3) the receptors form large clusters.

e. (1) trans-interactions between the receptors promote cis-dimerization; (2) calcium promotes receptor clustering; (3) the receptors interact with actin.


23. Assuming Hardy-Weinberg equilibrium, the genoypte frequency of heterozygotes, if the frequency of the two alleles at the gene being studied are 0.6 and 0.4, will be:a. 0.80b. 0.64c. 0.48d. 0.32e. 0.16

24. One of the reasons for glycosylation of proteins is to serve as a tag for unfolded proteins in the endoplasmic reticulum (ER). What is the role of glycosyl transferase in this process?a. It removes the 3 glucose residues that are

found at the end of N-linked oligosaccharides.

b. It is embedded in the membrane of the ER and binds to unfolded proteins, thereby preventing them from aggregating.

c. It binds to unfolded proteins in the lumen of the ER and adds glucose molecules, which then bind to calnexin.

d. It is the enzyme that adds a large preformed oligosaccharide onto asparagine residues in proteins.

e. It glycosylates calnexin and calreticulin allowing them to interact and help to properly fold proteins that are unfolded.

25. You have digested a plasmid with EcoRI and expect to obtain fragments 5000 bp, 3000 bp, and 2000 bp in length. You want to clone the 2000 bp fragment into another vector and to be able to do this you need to obtain 1 μg of the desired 2000 bp fragment. Given that you will be using plasmid DNA at a concentration of 0.5 μg/μl, how many μl of plasmid DNA should you add to your EcoRI digest?a. 2 μlb. 5 μlc. 10 μld. 4 μle. 8 μl

26. Of the 20 standard amino acids, only ___________ is not optically active. The reason is that its side chain ___________.a. proline; forms a covalent bond with the

amino group.b. alanine; is a simple methyl group.c. glycine; is unbranched.d. alanine; contains only hydrogen.e. glycine; is a hydrogen atom.

27. A hydronium ion: a. is a hydrated proton. b. is a hydrated hydrogen ion

c. has the structure H3O+.

d. is the usual form of one of the dissociation products of water in solution.

e. All of the above are true.

28. The gene coding for a soluble protein that is normally targeted to the lumen of peroxisomes is mutated so that an ER signal sequence is added to the encoded protein at the N-terminal end. The normal peroxisomal signalling sequence remains in the encoded protein. What is the most likely final destination of the protein?a. Lysosomes.b. The nucleus.c. The protein would be secreted from the

cell.d. Peroxisomes.e. The Golgi apparatus.

29. What is the function of Ran-GEF?a. It binds to nucleoporins ensuring that

cargo is transported out of the nucleus.b. It promotes the exchange of GDP for GTP

on Ran.c. It binds to the nuclear export signal of the

cargo protein.d. It transports the empty nuclear export

receptor into the nucleus.e. It enhances the intrinsic GTPase activity of

Ran.


30. The preparation of DNA for mitosis is most accurately described by which set of events?a. (1) During S phase, the chromatids

assemble kinetochores to interact with microtubules; (2) During prophase, condensins compact the chromatids and cohesins hold the chromatids together; (3) DNA is then duplicated to form sister chromatids.

b. (1) During S phase, condensins compact the chromatids and cohesins hold the chromatids together; (2) During prophase, the chromatids assemble kinetochores to interact with microtubules; (3) DNA is then duplicated to form sister chromatids.

c. (1) During S phase, DNA is duplicated to form sister chromatids; (2) During prophase, cohesins compact the chromatids and condensins hold the chromatids together; (3) The chromatids then assemble kinetochores to interact with microtubules.

d. (1) During S phase, cohesins compact the chromatids and condensins hold the chromatids together; (2) During prophase, the chromatids assemble kinetochores to interact with microtubules; (3) DNA is then duplicated to form sister chromatids.

e. (1) During S phase, DNA is duplicated to form sister chromatids; (2) During prophase, condensins compact the chromatids and cohesins hold the chromatids together; (3) The chromatids then assemble kinetochores to interact with microtubules.

31. Which of the following molecules is a product of the urea cycle that can be converted back to a substrate of the urea cycle?a. aspartateb. carbamoyl phosphatec. fumarated. malatee. oxaloacetate

32. The process of fatty acid synthesis involves all of the following except: a. A large multi-enzyme complex b. Acetyl CoA carboxylase c. NADPH d. Malonyl CoA e. CAT I (carnitine acyl transferase I)

33. One of the in vitro muscle systems required the addition of calcium ions. What is the critical role of calcium with respect to muscle contraction?a. Calcium is a necessary co-factor for

ATPase activity of the myosin head.b. Calcium binds to tropomyosin, which

sends a signal to troponin to pull tropomyosin out of its actin binding groove.

c. Calcium allows for the proper dynamics of the large titin protein.

d. Calcium binds to troponin, which releases tropomyosin into its normal binding groove so that the myosin heads can bind.

e. Calcium activates calmodulin, which sends a signal to the troponin complex to pull tropomyosin out of its actin binding groove, so the actin can bind to the myosin heads.

34. In a highly basic solution, pH = 13, the dominant form of glycine is: a. NH2—CH2—COOH.

b. NH3+—CH2—COOH.

c. NH2—CH2—COO⁻.

d. NH3+—CH2—COO⁻.

e. NH2—CH3+—COO⁻.

35. The single most important contribution to the stability of a protein's conformation appears to be the: a. sum of free energies of formation of many

weak interactions among the hundreds of amino acids in a protein.

b. entropy increase from the decrease in the number of ordered water molecules forming a solvent shell around a protein.

c. sum of free energies of formation of many weak interactions between a protein's polar amino acids and surrounding water.

d. maximum entropy increase from ionic interactions between the ionized amino acids in a protein.

e. stabilizing effect of hydrogen bonding in a protein between the carbonyl group of one peptide bond and the amino group of another, as indicated by —C¬O|||H—N—.


36. Skeletal muscle cells that have a functional insulin signalling pathway are treated with insulin. An hour later, a protein extract is made from the cells. Proteins in the extract are separated by SDS-PAGE and then the gel is blotted. The blot is incubated with antibodies that detect phosphoserine, phosphothreonine and phosphotyrosine residues in proteins. The blot is washed and then incubated with an appropriate secondary antibody to allow for detection of the primary antibodies. Which of the following proteins would you expect to detect on the blot? Give a complete list.

1. insulin receptor2. IRS-13. Grb24. Phosphatidylinositol 3-kinase (PI 3-kinase)5. PDK16. protein kinase B (PKB)

a. 2, 3, 4b. 1, 2, 3, 5, 6c. 4, 5, 6d. 1, 2, 5, 6e. 2, 4

37. Which type of regular light microscopy is the BEST for visualizing transparent internal structures in living cells?a. Bright-field microscopy.b. Transmission electron microscopy.c. Nomarski Imaging (Differential

Interference Contrast).d. Fluorescence microscopy.e. Confocal microscopy.

38. Suppose one were provided with an actively dividing culture of E. coli bacteria to which radioactive thymine has been added. What would happen if a cell replicated once in the presence of this radioactive base?a. One of the daughter cells but not the

other will have radioactive DNAb. Neither of the two daughter cells will be

radioactivec. All four bases of the DNA would be

radioactived. Radioactive thymine would pair with non-

radioactive guaninee. DNA in both daughter cells will be

radioactive

39. What is the correct enzyme name for the reaction drawn below?

a. acetoacetate dehydrogenaseb. β-hydroxybutyrate reductasec. β-hydroxybutyrate dehydrogenased. acetoacetate reductasee. β-hydroxybutyrate synthase

40. Vitamin deficiencies may affect many metabolic pathways due to the requirement of cofactors in enzymatic reactions. The Pentose Phosphate Pathway (PPP) can be run in one of four modes, depending on the specific purpose or product(s) needed (listed below). Which of these four modes of the PPP would NOT be affected by thiamine deficiency?

Mode #1: NADPH + Ribose-5-PMode #2: NADPH onlyMode #3: NADPH + energyMode #4: Ribose 5-P only

a. Mode 1b. Mode 2c. Mode 3d. Mode 4e. All modes

41. Which of the following statements concerning clathrin-coated vesicles is CORRECT?a. Arf-1 is a GTPase that is needed for the

formation of clathrin-coated vesicles.b. Clathrin-coated vesicles form in the

membrane of the endoplasmic reticulum.c. Clathrin-coated vesicles lack V-SNARES.d. Uncoating of clathrin-coated vesicles

requires a GAP protein.e. There is a single type of adaptor protein

that interacts with clathrin.


42. New experimental evidence was presented in class that favours the cisternal model of protein transport through the Golgi apparatus. In one experiment, a cis-Golgi resident protein was labelled with GFP and a trans-Golgi resident protein was labelled with RFP. Single cisternae were observed over time with 3D confocal microscopy. The researchers observed that greencoloured cisternae changed into red-coloured cisternae. Why did the green disappear or the red appear?a. The red appeared because the RFP-

labelled proteins were transported to the observed cisternae from the medial-Golgi.

b. The green disappeared because the GFP-labelled proteins were transported out of the observed cisternae in an anterograde direction.

c. The red appeared because the observed cisternae fused with the cisternae that contained the RFP-labelled proteins.

d. The green disappeared because the GFP-labelled proteins were transported out of the observed cisternae in a retrograde direction.

e. The green disappeared because the GFP-labelled proteins travelled through the Golgi and were secreted from the cell.

43. You are trying to create an artificial mitochondria with a new category II prosthetic group to replace cytochrome c. You have named this new prosthetic group substance X. Given the standard redox potentials of the two half reaction:

Substance X+ + 2H+ + 2e- Substance X Eo’ = 0.25½O2 + 2H+ + 2e- H2O Eo’ = 0.75

What is the standard free energy change of the following reaction?

Substance X + ½O2 Substance X+ + H2O(Given ΔGo’ = - n FΔEo’ and F = 23 kcal/volt mol e-)

a. - 46 kcal/molb. – 23 kcal/molc. + 46 kcal/mold. + 23 kcal/mole. -11.5 kcal/mol

44. A cell containing 92 chromatids at metaphase of mitosis would, at its completion, produce two nuclei each containing how many chromosomes?a. 12b. 23c. 46d. 92e. 184

45. The light reactions of photosynthesis occur in what structure of the chloroplast?a. thylakoid membraneb. chlorophyll moleculec. stroma of the chloroplastd. cytoplasm surrounding the chloroplaste. outer membrane of the chloroplast

46. The molecule shown below can be converted into which of the following molecules by a transamination reaction? a. lactate

b. acetyl CoAc. aspartated. alaninee. glutamate

47. Which of the following correctly pairs a pathway with one of its regulated enzymes?a. TCA cycle: fumaraseb. beta-oxidation of fatty acids: CAT IIc. glycolysis: phosphoglycerate kinased. fatty acid synthesis: pyruvate carboxylasee. urea cycle: carbamoyl phosphate

synthetase I (CPS I)

48. Which of the following enzymes is the common activator of the pancreatic zymogens involved in polypeptide breakdown in the small intestine?a. Pepsinb. Carboxypeptidase Ac. Elastased. Aminopeptidasee. Trypsin


The following 2 questions refer to the pathway drawn above. The letters in brackets [ ] represent additional substrates and products for the reactions indicated.

49. Which of the following statements regarding the above pathway is CORRECT?a. Biotin provides the “long arm” of the

complex that carries out these reactions.b. Reaction 3 is a hydration reaction.c. The committed step of this pathway

produces the three carbon unit of molecule B.

d. The enzymes that carry out reactions 2 and 4 are dehydrogenases.

e. Reaction 2 requires NAD+ (molecule [H]) and Reaction 4 requires FAD (molecule [K]).

50. In a liver cell, molecule F (after it is released) could be immediately used by that same liver cell for which of the following pathways:a. Ketone body synthesis onlyb. Triacylglycerol synthesis onlyc. Phospholipid synthesis onlyd. Triacylglycerol synthesis or phospholipid

synthesise. Ketone body synthesis or triacylglycerol

synthesis or phospholipid synthesis


51. Which statement about microarray experiments is FALSE?a. They are based on DNA:DNA hybridizationb. They are based on competitive hybrization

using two different pools of nucleic acids

c. They used fluorescent labelingd. They can be used to scan the expression

of many genes simultaneouslye. They can be useful in screening for genetic

diseases

52. What is the co-transduction frequency for the A and B genes, from the following dataset? (Assume that there has been selection for the A+ form of the A gene).Genotype NumberA+B+ C+ 10A+B+ C- 30A+ B- C+ 20A+ B- C- 40

a. .10b. .20c. .30d. .40e. .50

53. Regarding intermediate filaments, which of the following statements is TRUE?a. Intermediate filaments composed of one

type of protein are found in all cells.b. Intermediate filaments are named

“intermediate” because their ability to withstand force and deformation is intermediate between that of microtubules and actin filaments.

c. Keratin and collagen are two types of intermediate filaments.

d. Some intermediate filaments can interact with adhesion complexes and others strengthen the cell nucleus.

e. Intermediate filaments are polarized.

54. Which of the following molecules is a major link between the extracellular matrix and integrins?a. collagenb. actinc. elastind. aggrecan

e. laminin

55. 6. A compound has a pKa of 7.4. To 100 mL of a 1.0 M solution of this compound at pH 8.0 is added 30 mL of 1.0 M hydrochloric acid. The resulting solution is pH:a. 7.58.b. 7.4. at pH=8.0 A/HA = 4/1 or 80mmols

A / 20mmols HAc. 7.22. 30mmols of HCl will convert

30mmols of A to HAd. 6.8. this gives a final ratio of

50mmols/50mmols. pH=pKe. 6.53.

56. The chirality of an amino acid results from the fact that its alpha carbon:a. is a carboxylic acid.b. is bonded to four different chemical

groups.c. is symmetric.d. is in the L absolute configuration naturally

occurring proteins.e. has no net charge.

57. Which of the following would you add to a tube containing bacterial DNA if you wanted to make many copies of a portion of the 16S rRNA gene using PCR?a. dNTPs, lysozyme, buffer with Mg2+, RNA

primers, and waterb. dNTPs, DNA polymerase, buffer with

Mg2+, DNA primers, and waterc. ddNTPs, DNA polymerase, buffer with

Mg2+, DNA primers, and waterd. dNTPs, DNA polymerase, buffer with

Mg2+, RNA primers, and watere. dNTPs, reverse transcriptase, buffer with

Mg2+, DNA primers, and water

58. What is the BEST way to determine the size of a particular transcript in a specific cell type?a. Perform a microarray analysis.b. Perform a luciferase assay.c. Perform a Northern blot.d. Perform a Gel-Mobility Shift Assay (or

EMSA)e. Perform a Chromatin

Immunoprecipitation assay.

59. Which of the following are primarily responsible for cytokinesis in plant cells?a. chromatid condensationb. Golgi-derived vesiclesc. actin and myosind. centrioles and basal bodies


e. cyclin-dependent kinases

60. The following experiment was performed to examine the unfolded protein response. One group of yeast cells was treated with a chemical that causes the unfolded protein response, while another group of cells remained untreated. RNA and protein were isolated from both groups of cells and northern and western blots were performed. The northern blot was probed with DNA that is complementary to an exon that is present in RNA coding for a gene regulatory protein that regulates the unfolded protein response. The western blot was probed with an antibody that is specific for the gene regulatory protein. Which of the following is the BEST answer for what you would expect to observe?a.

Sample Northern WesternUntreated cells Band present No band

Treated cells Band present same weight as untreated

Band present

b.Sample Northern Western

Untreated cells Band present No bandTreated cells Band present smaller

weight than untreatedBand present

c.Sample Northern Western

Untreated cells Band present No bandTreated cells Band present larger

weight than untreatedBand present

d.Sample Northern Western

Untreated cells No band Band presentTreated cells Band present Band present smaller

weight than untreatede.

Sample Northern WesternUntreated cells No band No band

Treated cells Band present Band present

61. A siRNA from humans was found and characterised. When the siRNA was introduced as double-stranded RNA (dsRNA) back into an undifferentiated human cell line, the cells differentiated into blood cells. A siRNA with a different sequence did not have this effect; cells remained undifferentiated when dsRNA corresponding to this second siRNA was introduced into the cell line in an independent experiment. Together, these results indicate that:a. a) the second siRNA is not a good control

for this experiment.b. the first siRNA activates a gene that is

itself an activator of blood cell differentiation.

c. the first siRNA represses a gene that is itself a repressor of blood cell differentiation.

d. the second siRNA competes with the first siRNA to regulate blood cell differentiation.

e. the RISC is not involved in the recognition of the second siRNA to cause DNA methylation.

62. Which of the following statements CORRECTLY completes the following phrase? During the process of ubiquitination (ubiquitylation),a. the carboxy terminus of ubiquitin is

initially activated through a high-energy thioester linkage to a cysteine side chain of the ubiquitin activating enzyme, E1.

b. E1 and E2 proteins together form the ubiquitin ligase complex that binds to a degradation signal on the target protein.

c. the amino terminus of ubiquitin is initially activated through a high-energy thioester linkage to a cysteine side chain of the ubiquitin activating enzyme, E1.

d. E2 and E3 proteins together form the ubiquitin activating enzyme that transfers ubiquitin to E1 ligase before E1 ligase


binds to the degradation signal on the target protein.

e. the carboxy terminus of ubiquitin is initially activated through a high-energy thioester linkage to a cysteine side chain of the ubiquitin activating enzyme, E3.

63. In the yeast two-hybrid assay, what is the role of the GAL4 gene?a. The GAL4 gene provides the upstream

activating sequences that allow the expression of the LEU gene when the “bait” and “prey” fusion proteins have interacted.

b. The GAL4 gene is included on the bait plasmid as a selectable marker, as the yeast strain that is used is gal-.

c. The GAL4 gene provides the coding sequences for the GAL4 protein DNAbinding domain that comprise part of the “bait” fusion protein, and the coding sequences for the GAL4 protein transcriptional activation domain that comprise part of the “prey” fusion protein.

d. The GAL4 gene encodes an enzyme that is a reporter that indicates when the “bait” and “prey” fusion proteins have interacted and activated transcription.

e. The GAL4 gene is used to indicate the extent of transformation efficiency when the yeast strain has been transformed with the bait plasmid.

64. Ribosomal RNA is transcribed from multiple copies of a specific operon in prokaryotes. Which of the following is the CORRECT order in descending size of the transcripts from that operon (from largest to smallest):a. 16S rRNA 23S rRNA 5S rRNA tRNAb. 23S rRNA 16S rRNA mRNA 5S rRNA tRNAc. 23S rRNA 16S rRNA 5S rRNA tRNAd. 16S rRNA 23S rRNA mRNA 5S rRNA tRNAe. tRNA 16S rRNA 23S rRNA mRNA 5S rRNA

65. Suppose that an exceptional girl is born who has three copies of chromosome 22, and she survives to early adulthood. Which of the following characteristics would you NOT expect to find in this woman?a. Lower than average fertilityb. Health problems involving multiple organ

systemsc. Uneven pairing of some chromosomes

during meiosis

d. Two Barr bodies per celle. Production of some unbalanced gametes

(eggs)

66. How would you best describe the caspase signaling pathway?a. An inverted pyramid in which many

separate signals at the top converge to elicit one final molecular effect.

b. A single pathway in which a signal at the top elicits one final molecular effect in the nucleus.

c. A single pathway in which a signal at the top elicits one final molecular effect in the mitochondria.

d. A normal pyramid in which one initial signal at the top can elicit many separate molecular effects.

e. A disorderly pathway associated with necrosis.

67. DNA polymerase III moves in which direction along the DNA?a. 3´ → 5´ along the template strandb. 3´ → 5´ along the coding (sense) strandc. 5´ → 3´ along the template strandd. 3´ → 5´ along the coding strande. 5´ → 3´ along the double-stranded DNA

68. Which of the following statements concerning the mitotic spindle is INCORRECT?a. Astral microtubules extend towards the

plasma membrane.b. Overlapping microtubules pull the

centrosomes together.c. Kinetochore microtubules form between

centrosomes and centromeres.d. The movement of chromosomes involves

microtubule disassembly.e. A functional spindle involves both plus-

and minus-end directed microtubule motor proteins.

69. Which of the following statements about excision repair is incorrect?a. Excision repair is always initiated by

specific enzymes that recognize damaged DNA.

b. Excision repair removes a region of DNA that extends beyond the damaged bases on either side.


c. The gap resulting from an excision must be filled in by special repair enzymes (e.g. endonucleases).

d. Excision repairs all require an undamaged template strand.

e. Excision repair usually results in a perfectly restored DNA helix.

70. The pathways of protein degradation involve all of the following except:a. The lysosomal pathway primarily degrades

proteins from endocytosis.b. The attachment of ubiquitin to proteins

requires ATP.c. The proteasome degrades ubiquinated

proteins.d. Only one molecule of ubiquitin is attached

to a protein to be degraded.e. The lysosomal pathway uses a variety of

proteases to degrade proteins.

71. What are the products of beta-oxidation of a C14 fatty acid?a. 1 propionyl CoA, 6 acetyl CoA, 6 FADH2,

and 6 (NADH + H+)b. 8 acetyl CoA, 7 FADH2, 7 (NADH + H+)c. 6 acetyl CoA, 5 FADH2, 5 (NADH + H+)d. 7 acetyl CoA, 7 FADH2, 7 (NADH + H+)e. 7 acetyl CoA, 6 FADH2, 6 (NADH + H+)

72. What is the correct sequence of enzymes for the four repeated steps of β- oxidation of fatty acids?a. carnitine acyl transferase I (CAT I),

carnitine acyl transferase II (CAT II), β-hydroxyacyl-CoA, β-ketothiolase

b. acyl CoA dehydrogenase, enoyl CoA dehydratase, β-hydroxyacyl CoA dehydrogenase, β-ketothiolase

c. β-ketoacyl ACP synthase, β-ketoacyl ACP reductase, β-hydroxyacyl ACP dehydratase, enoyl ACP reductase

d. acyl CoA dehydrogenase, enoyl CoA hydratase, β-hydroxyacyl CoA dehydrogenase, β-ketothiolase

e. acyl CoA reductase, enoyl CoA hydratase, β-hydroxyacyl CoA reductase, β-ketothiolase

73. If the frequency of males affected with an X-linked recessive condition in a human population is .10 (one in ten), what will be the expected frequency of affected females?a. 0.0001b. 0.001

c. 0.02d. 0.01e. 0.05

74. Mitochondrial DNA is advantageous for evolutionary studies because:a. it is inherited only through the female

parent and thus evolves in a way that allows trees of relationship to be easily constructed

b. it is inserted into the X chromosomec. it first appeared in humans and is not

found in other animalsd. it evolves more slowly than the genes in

the nucleuse. it was derived from the globin genes as an

extra copy

75. You would like to determine how a specific membrane protein is anchored to the plasma membrane. You express a fusion protein in cells in which the protein of interest is fused to GFP. As expected, most of the fluorescence is localized to the plasma membrane. You then add phospholipase C to the medium bathing the cells. The fluorescence disappears from the membrane. What can you conclude?a. The protein is anchored via its

transmembrane region, which is composed of amino acids.

b. The protein is a peripheral protein.c. The protein is anchored via a prenyl

anchor.d. The protein is anchored via a

glycosylphosphatidylinositol anchor.e. The protein is anchored via a fatty acid

chain.

76. Complex V (ATP synthase) is most accurately described by which of the following?

a. Requires NAD+ to transfer protons across membrane

b. Is comprised of two portions, one to allow proton flow and one to synthesize ATP

c. Produced ATP is released directly into the cytoplasm

d. Antimycin inhibits Complex V by stopping the flow of protons

e. Its inhibition has no effect on mitochondrial oxygen consumption


77. In the Watson-Crick model of DNA structure (B-form DNA): a.the 5' ends of both strands are at one end of

the helix, and both 3' ends are at the other end of the helix.

b. the bases occupy the interior of the helix. c. a purine in one strand always hydrogen

bonds with a purine in the other strand. d. G–C pairs share two hydrogen bonds. e. A–T pairs share three hydrogen bonds.

78. RFLP analysis is a technique thata. uses hybridization to detect specific DNA

restriction fragments in genomic DNAb. is used to determine whether a gene is

transcribed in specific cellsc. measures the transfer frequency of genes

during conjugationd. is used to detect genetic variation at the

protein level.e. is used to amplify genes for producing

useful products

79. What is the name given to viruses that have single-stranded RNA that acts as a template for DNA synthesis in the host cell?a. retrovirusesb. provirusesc. bacteriophagesd. prionse. phages

80. Following the consumption of a high carbohydrate meal what following group of enzymes would you expect to be POSITIVELY regulated? a. pyruvate dehydrogenase, hexokinase,

phosphofructokinase b. fructose 1,6-bisphosphatase,

phosphofructokinase, hexokinase c. phosphoenolpyruvate carboxykinase,

pyruvate kinase, pyruvate carboxylase d. glycogen phosphorylase, pyruvate

dehydrogenase, glucokinase e. phosphofructokinase,

phosphoenolpyruvate carboxykinase, glucokinase

81. What functional groups are present on this molecule? CH2-CH2-CHO | OH a. hydroxyl and carboxylic acidb. hydroxyl and aldehydec. hydroxyl and ketoned. ether and aldehydee. hydroxyl and ester

82. Which of the following statements about the synthesis of double-stranded cDNA in vitro is TRUE?a. cDNA is made by the activity of an RNA-

dependent RNA polymerase.b. The synthesis of the second strand takes

place after the degradation of the original RNA template by RNAse H.

c. The enzyme that is used to synthesise the first strand of the cDNA is derived from the bacterial virus, bacteriophage lambda.

d. The first strand of the cDNA is primed by a polyA primer that binds to the 3’ end of the RNA template.

e. The first strand of the cDNA is primed by a polyT primer that binds to the 5’ end of the RNA template.

83. The gene cI of the bacteriophage lambda was mutated so that its gene product was no longer able to bind to DNA. What would you expect?a. The helix-loop-helix domain of the cro

protein would no longer bind to its target DNA.

b. The bacteriophage would not be able to sustain the lytic state.

c. The bacteria would always be in the lysogenic state.

d. The cI gene would always be turned off by the cro protein.

e. The cro protein would not be produced.


84. Prosthetic groups in the class of proteins known as glycoproteins are composed of:a. lipids.b. phosphates.c. carbohydrates.d. flavin nucleotides.e. metals (e.g., molybdenum).

85. In a mixture of the five proteins listed below, which should elute second in size-exclusion (gel filtration) chromatography?a. cytochrome c, Mr = 13,000b. immunoglobulin G, Mr = 145,000 (next to

largest)c. ribonuclease A, Mr = 13,700d. RNA polymerase, Mr = 450,000e. serum albumin, Mr = 68,500

86. To determine the isoelectric point of a protein, a gel is first established that:a. exhibits a stable pH gradient when

ampholytes become distributed in an electric field.

b. contains a denaturing detergent that can distribute uniform negative charges over the protein's surface.

c. relates the unknown protein to a series of protein markers with known molecular weights, Mr.

d. is washed with an antibody specific to the protein of interest.

e. neutralizes all ionic groups on a protein by titrating them with strong bases.

87. One hundred mL of 0.1 M NaOH is added to 55

mL of 0.2 M lactic acid. (The pKa of lactic acid

is 4.1.) The resulting mixture has a pH close to: a. 2. b. 3. c. 4. d. 5. e. 6.

88. Which of the following are all POSITIVE

regulators of fatty acid synthesis?a. ATP, citrate, glucagonb. Insulin, citrate, ATPc. Palmitoyl CoA, AMP, insulin

d. Glucagon, epinephrine, citratee. Palmitoyl CoA, AMP, glucagon

89. Which of the following is a step in the model of Na+/K+ pump action?a. The pump is not phosphorylated, instead

the hydrolysis of ATP simply provides energy.

b. In one conformation, 3 Na+ ions bind to high affinity sites on the extracellular face.

c. Na+ ions dissociate from low affinity sites on the cytosolic face.

d. Na+ ions and K+ ions are transported through the pump simultaneously.

e. In one conformation, 2 K+ ions bind to high affinity sites on the exoplasmic face.

90. Glucose uniporters are a family of proteins that transport glucose. Which of the following concerning these uniporters is CORRECT?a. GLUT-2 has a high Km indicating that it has

a high affinity for glucose.b. GLUT-4 is localized to plasma membranes

of fat and muscle cells when insulin levels are low.

c. GLUT-1 supplies glucose to most cells of the body independent of insulin concentrations.

d. GLUT-1 has a low Km indicating that it has a low affinity for glucose.

e. At low glucose concentrations, the rate of transport through GLUT-2 is faster than the rate of transport through GLUT-1.

91. Which of the following ARE features of X chromosome inactivation?

i. XIST RNA induces heterochromatin formation.ii. Hyperacetylation of histones associated with the X chromosome.iii. DNA methylation of the X chromosome.iv. Formation of Barr bodies in mammalian males, ensuring dosage compensation.v. Seeding of euchromatin formation by the X-inactivation centre.vi. Translation of XIST RNA into a DNA methylase.

a. i, ii, ivb. i, ii, iii, v, vic. ii, iii, v


d. i, iiie. ii, iii, vi

92. The following is a gel showing the results of manual sequencing. What is the sequence of the template strand in the 5’ to 3’ direction?

a. 5’ TCGCAAGCTGA 3’b. 5’ ACGCTTGCAGT 3’c. 5’ TCAGTTCGCGA 3’d. 5’ TCAGCTTGCGA 3’e. None of the above

93. In the α-helix the hydrogen bonds: a. are perpendicular to the axis of the helix. b. occur mainly between electronegative

atoms of the R groups. c. occur mainly between electronegative

atoms of the backbone. d. occur only between some of the amino

acids of the helix. e. occur only near the amino and carboxyl

termini of the helix.

94. Which of the following complexes is most likely to act as a green light to progress though a cell cycle check point?a. non-phosphorylated cyclin E bound to

phosphorylated Cdk2b. phosphorylated cyclin E bound to non-

phosphorylated Cdk2c. non-phosphorylated cyclin E bound to

non-phosphorylated Cdk2d. phosphorylated cyclin E bound to

phosphorylated CAKe. phosphorylated cyclin E bound to non-

phosphorylated CAK

95. Which organelle is primarily involved in the synthesis of phospholipids and steroids?a. ribosomeb. chloroplastc. Golgi apparatusd. smooth endoplasmic reticulum (ER)e. nuclear envelope

96. Which of the following statements concerning ATP synthase and the synthesis of ATP is NOT correct?a. ATP synthase contains a transmembrane

F0 region through which protons travel.b. The energy supplied as protons move

down their electrochemical gradient is converted to mechanical energy.

c. ATP synthases are of ancient origin and occur in plants, animals and bacteria.

d. ADP and Pi bind to subunits in the F1 region where they are converted to ATP.

e. V-type ATPases pump protons into the intermembrane space of mitochondria to generate a gradient that provides the energy for ATP synthesis.

97. Which of the following statements about glucagon and epinephrine is incorrect?a. The release of glucagon and epinephrine

both involve a response to low blood sugar.

b. Muscle is a target tissue for both glucagon and epinephrine.

c. Epinephrine is derived from tyrosine.d. Both glucagon and epinephrine bind to G-

protein coupled receptors.e. Epinephrine inhibits glucose uptake from

the blood in muscle tissue.

98. The enzyme glyceraldehyde 3-phosphate dehydrogenase (GAPDH) is involved in the energy transfer of the glycolytic pathway. Which of the following statements does NOT accurately describe GAPDH? a. Under anaerobic conditions it requires

lactate dehydrogenase to supply NADH b. Contains a free sulfhydryl necessary to

bind the substrate c. Produces a high energy intermediate that

is used for substrate level phosphorylation d. Utilizes inorganic phosphate to produce

1,3-bisphosphoglycerate e. The substrate glyceraldehyde 3-phosphate

is oxidized to form a high energy thioester


99. The compound that consists of ribose linked by an N-glycosidic bond to N-9 of adenine is: a. a purine nucleotide. b. a pyrimidine nucleotide. c. adenosine. d. AMP e. a deoxyribonucleoside.

100. In B-DNA each deoxyribose is in the C-2' endo conformation. This means that it is a. the furanose ring is completely planar b. the 2' carbon is in the same plane as the 5'

carbon c. the 2' carbon is in the same plane as the

furanose ring oxygen d. the 2' carbon is on the same side of the

furanose ring as the 5' carbon e. the 2' carbon is on opposite side of the

furanose ring from the 5' carbon

101. Which of the following is a mirror repeat? a. GGATCC

CCTAGG b. GTATCC

CATAGG c. GAATCC

CTTAGG d. AGGTCC

TCCAGG e. CCTTCC

GCAAGG

102. The three-dimensional conformation of a protein may be strongly influenced by amino acid residues that are very far apart in sequence. This relationship is in contrast to secondary structure, where the amino acid residues are: a. always side by side. b. generally near each other in sequence. c. generally on different polypeptide strands. d. generally near the polypeptide chain's

amino terminus or carboxyl terminus. e. restricted to only about seven of the

twenty standard amino acids found in proteins.

103. Which of the following statements about electron microscopy is TRUE?a. Scanning electron microscopy (SEM) is

generally used to view internal cellular structures.

b. The wavelength of a beam of electrons is about 1000 times shorter than that of visible light.

c. Glass lenses are used to focus the electron beam.

d. The achievable resolution of electron microscopy is similar to that of light microscopy.

e. Transmission electron microscopy (TEM) can be combined with the metal shadowing process to view external cellular structures.

104. Which of the following statements regarding aminotransferases (a.k.a. transaminases) is incorrect?a. High serum levels of alanine

aminotransferase (ALT) may indicate liver damage.

b. Aminotransferase reactions are irreversible.

c. Aminotransferases require a co-factor derived from vitamin B6.

d. The co-factor of the aminotransferase is attached to the enzyme via a Schiff base.

e. Glutamate is often a product of aminotransferase reactions.

105. Which of the following statements is correct? a. CTP is used to activate phosphatidate in

phospholipid synthesis. b. All of the carbons in cholesterol synthesis

come from malonyl CoA. c. Phospholipases are used in the synthesis

of phospholipids. d. HMG-CoA synthase catalyzes the

committed step of cholesterol synthesis. e. Sphingosine is derived from palmitoyl CoA

and glycerol phosphate.

106. The regulation of cholesterol synthesis involves which of the following: a. glucagon dephosphorylates HMG-CoA

reductase


b. cholesterol increases the synthesis of HMG-CoA reductase

c. cholesterol increases the synthesis of the LDL receptor

d. cholesterol inhibits the activity of HMG-CoA reductase

e. cholesterol inhibits the degradation of HMG-CoA reductase

107. Lipoprotein particles are able to transport lipids, which are hydrophobic, through the blood becausea. they have a hydrophilic surface and a

hydrophobic interior.b. they contain bile salts to emulsify the

lipids.c. they attach the triacylglycerols to albumin.d. they have a phospholipid bilayer

containing integral membrane proteins.e. they degrade the lipids to form ketone

bodies.108. At which oxidation level does biotin, a cofactor

in pyruvate carboxylase and acetyl CoAcarboxylase, transfer one-carbon units?a. –CH3b. –CO2c. –CH2-d. –CH=Oe. =CH-

109. Which two enzymes are used in the catabolism of all pyrimidine nucleotides?a. pyruvate carboxylase and acetyl CoA

carboxylaseb. PRPP (5-phosphoribosyl-1-pyrophosphate)

synthetase and PRPP amido transferasec. 5’-nucleotidase and nucleoside

phosphorylased. ribonucleotide reductase and thymidylate

synthasee. adenine phosphoribosyl transferase and

hypoxanthine-guanine phosphoribosyl transferase

110. A simple transposon:a. is a DNA segment that codes for an

enzyme for its own insertion into other DNA sequences

b. is a DNA segment that codes for several genes, including one for its own insertion

c. is found only in chloroplastsd. is the kind that never moves around in the

genomee. codes for the lactose operon

111. A bacterial plasmid is:

a. the same as a transposable elementb. as large as the bacterial chromosomec. an extrachromosomal piece of DNAd. never inserted into the bacterial

chromosomee. a control element for crossing over

112. A pure-breeding collie (long-haired dog) is bred to a pure-breeding pointer (short-haired dog). The puppies have a variety of intermediate hair lengths; some are much shaggier than others. What kind of genetic effect is this?a. epistasisb. pleiotropyc. pseudoautosomal inheritanced. variable expressivitye. incomplete penetrance

113. Which of the following statements regarding the regulation of beta-oxidation of fatty acids is correct?a. Beta-hydroxyacyl CoA dehydrogenase is

activated by high NADH concentrations.b. Palmitate is an inhibitor of beta-oxidation.c. Beta-ketothiolase is activated by high

acetyl CoA concentrations.d. Carnitine acyl transferase I (CAT I) is

inhibited by high malonyl CoA concentrations.

e. Insulin stimulates the beta-oxidation of fatty acids.

114. In a plot of l/V against 1/[S] for an enzyme-catalyzed reaction, the presence of a competitive inhibitor will alter the: a. Vmax.

b. intercept on the l/V axis. c. intercept on the l/[S] axis. d. curvature of the plot. e. pK of the plot.

115. Which of the following proteins is NOT a component seen in the sliding filament contraction model?a. Titinb. Nebulinc. Cadherind. Myosine. CapZ


116. Which of the above molecules is the key intermediate (“branch point”) in the pathways ofphosphosphingolipid and glycolipid synthesis?a. A) molecule 1b. B) molecule 2c. C) molecule 3d. D) molecule 4e. E) molecule 5

117. What does NOT happen in a binding site selection assay between a DNAbinding protein and DNA?a. Increasing concentrations of unlabelled

competitor DNA are added to examine the specificity of the interaction.

b. The process starts by allowing a protein to interact with a pool of random oligonucleotides that have been radioactively labelled.

c. Shifted bands are excised from the gel and the DNA used as template in a PCR reaction.

d. Following the final round of selection, the DNA is cloned into plasmids and the inserts from many plasmids are sequenced.

e. The binding site is enriched in each round of selection, ultimately revealing the subset of DNA sites that the protein is most likely to bind

118. After double fertilization occurs in an angiosperm:a. the embryo is haploidb. the endosperm is triploidc. the embryo is triploidd. the endosperm is diploid

e. the endosperm is haploid

119. Which of the following transporters is correctly matched with what it transports?a. Carnitine: fatty acidsb. LDLs: dietary triacylglycerols (TAGs)c. Citrate: malonyl CoAd. Albumin: ketone bodiese. Glycerol-phosphate: protons (H+)

120. Which of the following statements most accurately describes the processes in the liver under conditions in which gluconeogenesis (GNG) is necessary? a. The consumption of alcohol would inhibit

GNG because of the excess NADH its breakdown produces

b. Glucose 6-phosphatase activity would be activated by high intracellular glucose

c. A pyruvate transporter will be active to bypass the phosphoglycerate kinase step of glycolysis

d. Excess fructose 1,6-bisphosphate will feed forward to activate pyruvate kinase

e. Cytosolic oxaloacetate would be converted to malate

121. QTL analysis is used to:


a. identify RNA polymerase binding sitesb. map genes in bacterial virusesc. determine which genes are expressed at a

developmental staged. identify chromosome regions associated

with a complex trait in a genetic cross

e. determine the most rapidly-evolving parts of genes

122. A person is suffering from a mutation in a key enzyme involved in carbohydrate metabolism. You run a battery of tests and determine the patient is capable of processing glucose all the way to pyruvate at normal rates under standard conditions. During times of anaerobic stress, the patient has a decreased glycolytic capacity. Which of the following mutated enzymes is matched with the metabolite most likely to be found at abnormally high levels in this patient under anaerobic conditions?

Mutated enzyme Metabolite at high concentrationa. Glyceraldehyde 3-P dehydrogenase pyruvateb. Lactate dehydrogenase lactatec. Glyceraldehyde 3-P dehydrogenase dihydroxyacetone phosphated. Lactate dehydrogenase glyceraldehyde 3-phosphatee. Phosphofructokinase pyruvate

123. Which of the following groups contains enzymes all of which are capable of producing free ammonia (NH4+)?a. amino acid oxidases, glutaminase,

glutamate dehydrogenaseb. carbamoyl phosphate synthetase I (CPS I),

glutaminase, glutamine synthetasec. glutaminase, aminotransferases, amino

acid oxidasesd. glutamine synthetase, carbamoyl

phosphate synthetase I (CPS I), glutamate dehydrogenase

e. glutamate dehydrogenase, amino acid oxidases, aminotransferases

124. Assume that a particular human cell is examined under a microscope and it contains 22 autosomic chromosomes and a Y chromosome. The cell is most likely to bea. a somatic cell of a maleb. a somatic cell of an individual suffering

from Downs’s syndromec. a fertilized egg (a zygote)d. a somatic cell of a femalee. a sperm

125. Positional cloning refers to:a. using a selection procedure to clone a

cDNAb. cloning a portion of a gene using PCRc. isolating a gene by PCR using primers from

another speciesd. isolating a gene from a specific tissue in

which it is being expressed

e. mapping a gene to a chromosomal region and then identifying and cloning a genomic copy of the gene from the region

126. Which of the following statements about bacterial conjugation is incorrect?a. F+ cells act as genetic donors.b. Genes on the F factor encode proteins for

cell-cell contact and the formation of sex pili.

c. F+ cells convert F- cells into F+ cells.d. F' cells have especially high rates of

recombinatione. The F factor is transferred as a single

strand.

127. Which of the following does not involve cyclic AMP? a. regulation of glycogen synthesis and

breakdown b. regulation of glycolysis c. signaling by epinephrine d. signaling by acetylcholine e. signaling by glucagon


Directions: Each group of questions below consists of five lettered headings followed by a list of numbered words, phrases, or sentences. For each numbered word, phrase or sentence, select the one heading that is most closely related to it and fill in completely the corresponding space on the answer sheet. One heading may be used once, more than once, or not at all in each group.

Questions 128-132 refer to the following terms:

A. GMPB. UMPC. ATPD. dTMPE. dATP

128. Inhibits synthesis of PRPP (5-phosphoribosyl-1-pyrophosphate) from ribose 5-phosphate

129. Directly stimulates the overall activity of ribonucleotide reductase

130. 5-fluorouracil is the chemotherapeutic drug used to target the last enzyme in the synthesis of this Nucleotide

131. Activates methyl group of methionine132. Committed step in de novo synthesis of this

nucleoside monophosphate requires PRPP.


Match the phrases about gene regulation in prokaryotes to the terms in the list by putting a single letter in each blank. Not all letters need to be used, and a particular letter may be used more than once.

a. Effector molecule b. Activator c. Operator d. Inducible e. Repressor

133. Small molecule that binds to a regulatory protein to change its action

134. Binding site for regulatory proteins

135. Regulatory molecule that binds to operator region in DNA

136. Regulatory protein that promotes transcription


a. Light dependent reactionsb. Light independent reactionsc. Glycolysisd. Krebs cyclee. Electron transport system

137. Make ATP from light. 138. Breakdown glucose into smaller carbon

compounds. 139. Make sugar from CO2. 140. Make ATP and water. 141. Make ATP and split water.


a. Centrifugationb. Light microscopec. Scanning electron microscoped. Transmission electron microscopee. Paper chromatography

142. Examining the surface of cells.143. Looking at the internal structure of

chloroplasts. 144. Watching cells with flagella move. 145. Separating pigments of a leaf. 146. Isolating nuclei from cells.


Directions: Each group of questions below concerns a laboratory or an experimental situation. In each case, first study the description of the situation. Then choose the one best answer to each question and fill in completely the corresponding space on the answer sheet.


Worksheet for the Biochemistry Test Only


Total correct_________ :Total Incorrect________ :

Score____________ :

Answer Key and Percentages* of Examinees Answering Each Question Correctly

QuestionNumber Answer

1 D2 A3 D4 B5 C6 B7 D8 C9 D

10 B11 E12 A13 D14 E15 B16 E17 B18 C19 D20 E21 D22 C23 C24 C25 C26 E27 E28 C29 B30 E31 C32 E33 D34 C35 B36 D37 C38 E39 C40 A41 A42 D43 B44 C45 A46 D47 E48 E49 C50 D51 A52 D53 D54 E55 B56 B57 B58 C59 B60 B

Question

Number Answer61 C62 A63 C64 C65 D66 D67 A68 B69 C70 D71 E72 D73 D74 A75 B76 B77 B78 A79 A80 A81 B82 B83 D84 C85 B86 A87 D88 B89 E90 C91 D92 A93 C94 A95 D96 E97 B98 A99 C

100 D101 E102 B103 E104 B105 A106 D107 A108 B109 C110 A111 C112 D113 D114 C115 C116 E117 A118 C119 A120 A

QuestionNumber Answer

121 D

122 D123 A124 E125 E126 D127 D128 A129 C130 D131 C132 A133 A134 C135 E136 B137 A138 C139 B140 E141 A142 C143 D144 B145 E146 A147 D148 B149 B150 B151 C152 D153 -154 B155 A156 D157 -158 C159 D160 C161 C162 B163 C164 D165 B166 D167 E168 D169 C170 C171 D172 C173 D174 C175 B176 B177 B178 D179 B180 E


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