Microbiology 2124
Final Exam
Dec. 10, 1998
David Demezas

General Instructions: Multiple Choice. Choose the most correct answer and mark the corresponding letter on your scantron answer sheet.

1. Which of the following is unique to eukaryotic organisms (i.e., never found in prokaryotic organisms)?
A. A plasma membrane
B. Ribosomes
C. A cell wall
D. A membrane-bound nucleus
E. Enzymes

2. Which of the following is (are) required for bacteria to survive and grow?
A. Transcription
B. Translation
C. Replication
D. All of the above
E. None of the above.

3. True (A) or False (B). The cell is the fundamental unit of all living matter.

4. Which of the following scientist disproved the "theory of spontaneous generation"?
A. A. van Leeuwenhoek
B. L. Pasteur
C. R. Koch
D. R. Petri
E. W. Hesse

5. Which of the following pairs of sugars are the sugar backbone in the peptidoglycan layer?
A. Sucrose and Fructose
B. ribose and deoxyribose
C. N-acetyl glucosamine and glucose
D. N-acetyl muramic acid and fructose
E. N-acetyl glucosamine and N-acetyl muramic acid

6. The rigidity and shape of a bacterium is due to the _____.
A. cell membrane
B. peptidoglycan layer
C. the lipopolysaccharide
D. the teichoic acid layer
E. the flagella

7. Which of the following is NOT characteristic of a cell's cytoplasmic membrane?
A. a phospholipid bilayer
B. a highly selective permeability barrier
C. a hydrophobic core and hydrophilic layers on the outside
D. a very rigid (i.e., stiff) membrane
E. integral proteins that span the membrane

8. True (A) or False (B). Active transporters require some form of energy to transport molecules across the plasma membrane.

9. Which of the following enzymes would NOT be found in the periplasmic space of a Gram-negative bacteria?
A. lysozyme
B. transport proteins
C. chemoreceptors
D. hydrolytic enzymes

10. The above figure best illustrates the cell wall of __________.
A. a Gram - positive cell
B. protozoa
C. fungi
D. an Archaea cell
E. a Gram - negative cell

11. A sugar is chemically altered as it is transported across the cytoplasmic membrane into a cell. This is referred to as ____________.
A. group translocation
B. active transport
C. simple diffusion
D. osmosis
E. facilitated diffusion

12. The proton motive force may be used to ___________.
A. drive the flagella
B. generate ATP
C. transport molecules across the cytoplasmic membrane
D. reverse electron flow to generate NADPH
E. all of the above

13. Which of the following types of metabolism does Not generate a proton motive force that can be used to generate ATP?
A. aerobic respiration
B. anaerobic respiration
C. phototrophic
D. alcohol fermentation
E. chemolithotrophy

14. Which of the following best sums the result of aerobic respiration beginning with a molecule of glucose?
A. 2 x CO₂; 2 ATPs; 2 x ethanol
B. 2 x lactate; 2 ATPs
C. 2 x ethanol; 4 ATPs
D. 2 x pyruvate ; 4 ATPs
E. 6 x CO₂; 38 ATPs

15. Phototrophic bacteria generate ATP using _________ .
A. non cyclic photophosphorylation
B. oxidative phosphorylation
C. cyclic photophosphorylation
D. substrate level photophosphorylation
E. substrate level phosphorylation

16. Which of the following molecules cannot be used as a terminal electron acceptor in anaerobic respiration?
A. SO₄^2-
B. NO₃^-
C. CO₂
D. H₂S
E. All of the above.

17. Which of the following elements makes up the largest percentage of the dry weight of a cell?
A. oxygen
B. nitrogen
C. carbon
D. phosphorous
E. sulfur

18. True (A) or False (B). A complex medium is chemically undefined.

19. The end products of glycolysis are _______.
A. CO₂ and ATP
B. pyruvate, NADH and ATP
C. CO₂, pyruvate, NADH and ATP
D. CO₂, and NADH
E. ethanol and CO₂

Oxidation - reduction couple	Eo'
2 H+ + 2 e- ----> H2	-420 mV
1/2O2 + 2e- + 2H+ ----->H2O	+820 mV

20. True (A) or False (B). Given the above table and the following chemical equation: H₂ + 1/2 O₂ ------> H₂O. H₂ is the electron acceptor and O₂ is the electron donor.

21. Bacteria multiply by a process called _________.
A. meiosis
B. binary fission
C. replication
D. mitosis
E. fusion

22. You are given a culture with 10⁸ cells per ml of medium. What would be the population size of this culture after 6 generations?
A. 2 x 10⁹ cells per ml.
B. 8 x 10⁹ cells per ml.
C. 2 x 10⁸ cells per ml.
D. 6.4 x 10⁹ cells per ml.
E. 10¹⁴ cells per ml.

23. Which of the following is NOT characteristic of stationary phase?
A. Growth rate equals zero.
B. Nutrients are depleted.
C. Waste products are accumulating.
D. Growth rate is maximal for the species of bacteria.
E. All of the above.

24. Which of the following techniques counts both live and dead cells?
A. Spread plates
B. Pour plates
C. Turbidity
D. Direct microscopic counts
E. C and D

25. "Central dogma of molecular biology" states that genetic information flows from _____
A. RNA through DNA to protein.
B. protein through RNA to DNA
C. DNA through protein to RNA
D. DNA through RNA to protein
E. RNA through protein to DNA

26. The primer in DNA replication is _________.
A. an RNA starter sequence with a free 3´-OH group
B. an RNA starter sequence with a free 5´-OH group
C. a DNA starter sequence with a free 3´-OH group
D. a DNA starter sequence with a free 5´-OH group
E. a DNA starter sequence with a free 5´-phosphate group

27. Which of the following statements about RNA is False?
A. mRNA, tRNA and rRNA are the products of transcription.
B. rRNA is incorporated into ribosomes.
C. All RNAs are translated into polypeptides.
D. tRNAs carry amino acids to the growing polypeptide.
E. Only mRNA is translated into polypeptides.

28. Enzymatic activity of a pathway (e.g., biosynthesis of an amino acid) can be controlled by the endproduct inhibiting the first enzyme of the pathway. This is referred to as _________.
A. saturation
B. negative control
C. positive control
D. substrate inhibition
E. feedback inhibition

29. Repressors (e.g., lac repressor) and the catabolite activator protein are examples of ____________.
A. catalytic enzymes
B. allosteric proteins
C. terminators
D. coinducers

30. Which of the following statements is False about cells in the early part of the second phase of diauxic growth in a glucose/lactose based medium?
A. The lac repressor is bound to the inducer and cannot bind to the operator region.
B. The levels of cyclic AMP are elevated relative to the first phase of growth.
C. The lac operon is induced.
D. cAMP/CAP is bound to the CAP binding site.
E. All of the above statements are true.

31. Attenuation, an effective means of regulating amino acid biosynthetic genes in bacteria, requires _________.
A. a repressor
B. a activator protein
C. coupling of transcription and translation
D. an inducer
E. feedback inhibition

32. Which of the following pair is NOT correctly matched?
1. Transformation / Bacteriophage-mediated DNA transfer cell
2. Transduction / Uptake of DNA from the environment
3. Hfr / F-factor is integrated in chromosome
4. F ⁺ / F-factor separate from chromosome
5. F ^- / Recipient cell
A. 2 and 3
B. 1 and 5
C. 1 and 2
D. 2 and 4
E. 3 and 4

33. You have been bothered by food spoilage in the crisper drawer of your refrigerator. Most likely the microbial culprit is a/an ______.
A. psychrophile
B. mesophile
C. barophile
D. acidophile
E. thermophile

34. You have isolated a marine bacterium and verified its requirement for the marine environment for growth. You conclude that this bacterium is a/an _______.
A. osmophile
B. halophile
C. xerophile
D. none of the above

35. Which of the following is responsible for attaching nucleotides to the growing end of a DNA strand and proofreading each inserted nucleotide?
A. DNA helicase
B. DNA gyrase
C. DNA ligase
D. DNA polymerase III
E. None of the above

36. True (A) or False (B). Okazaki fragments are found on the leading strand during DNA replication.

37. Which of the following is a characteristic of the lagging strand synthesis?
A. Continuous synthesis of the lagging strand.
B. Synthesis of the lagging strand without a template strand.
C. The lagging strand is made without DNA polymerase.
D. Multiple RNA primers are needed for the lagging strand's synthesis.
E. All of the above are characteristic of lagging strand synthesis.

38. True (A) or False (B). A missense mutation results in a change in the amino acid sequence of a polypeptide; a silent mutation does not.

39. A codon is a sequence of three nucleotides coded for by __________.
A. DNA
B. messenger RNA (mRNA)
C. transfer RNA (tRNA)
D. ribosomal RNA (rRNA)
E. proteins

40. The Ames test uses auxotrophs with ________.
A. large deletions
B. microinsertions
C. temperature sensitive mutations
D. point mutations
E. transposon-induced mutations

41. Which of the following do Not include anoxygenic phototrophic species of bacteria?
A. Green sulfur bacteria
B. Green non sulfur bacteria
C. Purple non sulfur bacteria
D. Purple sulfur bacteria
E. Cyanobacteria

42. Nitrifiers carry out which of the following ecological functions in soils?
A. The reduction of ammonia to nitrate
B. The oxidation of methane to methanol
C. The reduction of sulfate to sulfide
D. The oxidation of ammonia to nitrate
E. The oxidation of hydrogen gas to protons

43. Which of the following is a Gram-positive, endospore-forming microorganism that produces an insecticidal protein?
A. Pseudomonas sp.
B. Azotobacter sp.
C. Bacillus sp.
D. Chromobacterium sp.
E. Klebsiella sp.

44. Escherichia, Enterobacter, Shigella, and Salmonella are all members of the group of bacteria called _______.
A. colonic bacteria
B. stomach bacteria
C. enteric bacteria
D. hemmorhagic bacteria
E. planktonic bacteria

45. True (A) or False (B) Cyanobacteria (Blue-green bacteria) are oxygenic phototrophs.

46. True (A) or False (B). Bacteriorhodopson is a membrane-associated protein that plays an integral role in the generation of the proton motive force in Halobacterium.

47. All hyperthermophilic Archaea have a temperature optimum of ______.
A. between 50 and 80^oC
B. above 80^oC
C. below 50^oC

48. True (A) or False (B). Extreme halophilic Archaea require at least 1.5 M (9% w/v) salt for growth.

49. True (A) or False (B). Most species of algae carry out oxygenic photosynthesis.

50. Which type(s) of metabolism is/are found in the fungi?
A. photoautotrophy
B. chemolithotrophy
C. chemoorganotrophy
D. photoheterotrophy
E. A, C, and D

51. Which of the following fungi does Not produce spores?
A. Deuteromycetes
B. Oomycetes
C. Zygomycetes
D. Basidiomycetes
E. Ascomycetes

52. Which of the following is an asexual spore?
A. basidiospore
B. ascospore
C. conidia
D. oospore
E. zygospore

53. Slime molds and protozoa obtain their food by _______.
A. photosynthesis
B. phagocytosis
C. transduction
D. osmosis
E. absorption

54. Which of the following viruses is/are a male-specific virus(es) that attach to the F-pili?
A. MS2
B. lambda
C. M13
D. lambda and M13
E. MS2 and M13

55. The temperate virus lambda DNA may integrate into the host bacterium's chromosome. Lambda is now referred to as a _________.
A. lysogen
B. prophage
C. plasmid
D. cosmid
E. transposon

56. Which two proteins play a central role in the decision whether lambda phage enters the lysogenic state or the lytic cycle?
A. cro and CI (lambda repressor)
B. cro and N
C. CII and N
D. CII and CIII E. N and CIII

57. True (A) or False (B). Virions are extremely infectious during the eclipse period of viral replication.

58. Bacteria have evolved _________ to defend against infection by bacteriophages by digesting the incoming viral DNA.
A. hydrogenases
B. topoisomerases
C. ligases
D. DNA polymerases
E. restriction endonucleases

59. The enzyme _________ comes from Thermus aquaticus and has revolutionized molecular biology in many ways.
A. Taq DNA polymerase
B. Taq RNA polymerase
C. Taq ligase
D. Taq restriction endonuclease
E. None of the above.

60. True (A) or False (B). Secondary metabolites are produced during the lag phase of growth.

61. True (A) or False (B). Fimbriae and the glycocalyx are major adherence factors facilitating the attachment of microbial pathogens to host tissue.

62. Which of the following is Not an enzyme associated with the invasion of the host by a bacterial pathogen?
A. hyluronidase
B. transferrin
C. collagenase
D. hemolysins
E. streptokinase

63. True (A) or False (B). Both host specificity and tissue specificity are important factors in the establishment of an infection by a pathogen in a host.

64. Which of the following is Not a exotoxin?
A. the cholera toxin
B. the tetanus toxin
C. the diphtheria toxin
D. the LPS of Salmonella
E. the botulinum toxin

65. _______ are exotoxins that act on the small intestine and cause massive fluid loss and diarrhea symptoms.
A. Siderophores
B. Enterotoxins
C. Transferrin
D. Hemolysins
E. None of the above.

66. In which organism is a toxin coded for by the genome of a resident phage?
A. Aspergillus niger
B. Corynebacterium diphtheriae
C. Bacillus megaterium
D. Escherichia coli
E. Staphylococcus aureus

67. Which of the following statements about toxins is false?
A. Exotoxins are generally more potent than endotoxins
B. Endotoxins are heat stable and exotoxins are heat labile.
C. Exotoxins are excreted into the surrounding environment.
D. Exotoxins rarely result in a fever; endotoxins often produce a fever in the host.
E. Endotoxins are produced by gram positive bacteria.

68. Which of the following is responsible for toxicity in Gram-negative bacteria?
A. KDO
B. Lipid A
C. Core polysaccharide
D. O-specific polysaccharide
E. Porins

69. Which of the following produces an enterotoxin that activates adenyl cyclase and a cascade of events that leads to massive loss of water and dehydration?
A. Vibrio cholerae
B. Staphylococcus aureus
C. Clostridium perfringens
D. Bacillus cereus
E. Escherichia coli

70. True (A) or False (B). Virulence, i.e., the degree of the ability of a parasite to cause disease, is determined by the invasiveness and toxigenicity of a pathogen.

71. ____ are inanimate objects, e.g., a toy, that transmit infectious agents between hosts.
A. Vectors
B. Carriers
C. Reservoirs
D. Fomites
E. Placebos

72. A mosquito transmitting malaria to a human is an example of a(n) _____.
A. endemic infection
B. biological vector
C. secondary infection
D. opportunistic pathogen
E. None of the above.

73. Diseases that occur naturally in animals, whereas man is an accidental host, are called ______.
A. epidemics
B. pandemics
C. zoonoses D. reservoirs E. carriers

74. True (A) or False (B). Transmission of infectious disease is most likely during the incubation period.

75. Typhoid Mary is an example of _____.
A. a chronic carrier
B. an acute carrier
C. an endemic
D. a pandemic
E. a famous epidemiologist

76. Which of the following is the correct order of the progression of disease.
A. Acute period, infection, incubation period, decline period, and convalescent period.
B. Infection, incubation period, acute period, decline period, and convalescent period.
C. Incubation period, acute period, decline period, infection, and convalescent period.
D. Acute period, decline period, incubation period, infection, and convalescent period
E. None of the above are correct.

77. True (A) or False (B). A common source epidemic is characterized by a sharp rise in the number of cases reported daily over a brief period of time.

78. Which of the following is the least common means of controlling epidemics?
A. Vector control
B. Immunization
C. Quarantine

79. Which of the following is Not a factor in emerging diseases?
A. Human demographics and behavior
B. Technological advances, e.g., antibiotic usage.
C. Changes in land use patterns
D. Microbial evolution
E. All of the above are factors in the emergence of new diseases.

80. True (A) or False (B). Nosocomial infections are infections contracted in a hospital.

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