Microbiology 2124
Final Examination-
Professor Robert V. Miller, Ph. D.
FORM A

General Instructions: Answer all questions on your test paper in the manner indicated. Only answers entered in the appropriate way will be marked. Read all questions carefully. Do not exceed space provided for the answer. Always provided the best right answer.
Part I: Multiple Choice and True and False. Circle the correct answer for each question. Two point for each question.
1. The often quoted statement made by Brefeld in the last century: "working with impure cultures can only lead to Penicillium and nonsense: clearly points out the importance of what aspect of microbiological technique?
A. use of a microscope
B. assigning a name to a specific microbe
C. essentiality of pure cultures for relating cause to effect
D. avoidance of studying microbes in nature

2. The specificity of an enzyme is determined by its structure, which in turn is established by its amino acid sequence.
True
False

3. The formation of messenger RNA is called translation.
True
False

4. The hallmarks of a cell include
A. nutrition
B. growth & differentiation
C. chemical signaling
D. evolution
E. all of the above

5. Bacteria were first seen in detail by _______ in ______.
A. Pasteur, 1861
B. van Leeuwenhoek, 1684
C. Hooke, 1664
D. Koch, 1876

6. The cell is the fundamental unit of all living matter.
True
False

7. Which of the following structures is never present in a prokaryotic cell?
A. cell wall
B. cell membrane
C. ribosomes
D. membrane-bound nucleus
E. flagella

8. Consider two cells: one is 1 micrometer wide, the other is 2 micrometers. When the surface-to-volume ratio is calculated for each, it is found that the ratio for the larger cell is one half that of the smaller. The shape of the cells must be:
A. cylindrical (a rod)
B. spherical (a coccus)

9. A membrane transport protein is being studied and it is noted that a second substrate is required for the transport of the first. Which type of transport protein is involved?
A. uniporter
B. symporter
C. antiporter

10. The enzyme, lysozyme, induces lysis in bacteria because it interferes with
A. transpeptidation which is essential for cross-linking
B. integrity of the -1,4 linkage between NAM and NAG
C. cell membrane selective permeability
D. all of the above

11. Which statement is not true? Porins:
A. are transmembrane proteins
B. exclude the passage of organic molecules
C. contain three identical subunits
D. usually have a low degree of specificity

12. Which of the following cell wall constituents would usually be found in fungi?
A. cellulose
B. silica
C. muramic acid
D. chitin

13. A bacterium is flagellated with flagella inserted at many points around the cell surface. What is this type of flagellation called?
A. monotrichous
B. lophotrichous
C. peritrichous

14. (I) Bacterial response to a spatial gradient determines the direction of motion. (II) Motile bacteria either are not influenced by a substance or they are attracted to it; they are never repelled.
A. only (I) is true
B. only (II) is true
C. both (I) and (II) are true
D. neither (I) nor (II) is true

15. Consider the conversion of a bacterial endospore to a vegetative cell: (I) Dormancy may be broken by heat treatment. (II) Outgrowth involves the action of new mRNA required for the production of new cellular material.
A. only (I) in true
B. only (II) is true
C. both (I) and (II) are true
D. neither (I) nor (II) is true

16. 70S ribosomes are found in
A. bacteria
B. mitochondria
C. chloroplasts
D. all of the above

17. Without doubt the most useful staining method for the microbiologist is the Gram stain which allows one to distinguish two major groups of bacteria.
True
False

18. The most variable entity in the peptidoglycan is the interbridge.
True
False

19. Endospore formation is associated with the exhaustion of essential nutrients.
True
False

20. Organisms that use organic chemicals as sources of carbon are properly called
A. phototrophs
B. lithotrophs
C. heterotrophs
D. organotrophs
E. chemoorganotrophs

21. The complete oxidation of pyruvic acid via the TCA (citric acid) cycle may result in the formation of how many ATPs via oxidative phosphorylation in bacteria?
A. 2
B. 11
C. 14
D. 15
E. 30

22. What type of linkage does the high energy bond of ATP possess?
A. hydrogen bond
B. ionic bond
C. ester linkage
D. ether linkage

23. The series of reactions which occur when glucose is fermented by yeast to form pyruvate is known as the
A. Krebs cycle
B. Pasteur effect
C. Embden-Meyerhof pathway
D. Calvin-Benson cycle
E. Glyoxalate by-pass

24. When hydrogen is removed from NADH on the inner side of the membrane what happens to the electrons and protons relative to the membrane?
A. electrons are extruded outside the membrane
B. electrons return to the cytoplasmic side via specific carriers
C. protons are extruded through the membrane
D (A) and (C)
E. (B) and (C)

25. The energized state of the membrane when protons are extruded quantitatively is expressed quantitatively as the:
A. redox potential
B. ATP potential
C. pH
D. proton motive force
E. proton gradient

26. Which of the following are characteristics of the ATPase involved in energy generation in respiration? (I) It is composed of a total of eight polypeptides. (II) The F1 component catalyzes the interconversion of ATP and ADP + P_i.
A. only (I) in true
B. only (II) is true
C. both (I) and (II) are true
D. neither (I) nor (II) is true

27. Membrane bound ATPase synthesizes ATP when:
A. protons move into cell
B. protons move out of cell
C. electrons move into cell
D. electrons move out of cell

28. At which stage of the aerobic utilization of glucose by a typical microbial cell is the most ATP generated?
A. glycolysis
B. oxidative decarboxylation of pyruvate
C. Citric acid (TCA) cycle
D. the electron transport system

29. (I) Anaerobic respiration involves the use of electron transport systems to generate ATP in which the final electron acceptor is not O₂. (II) Alternate electron acceptors to O₂ in anaerobic respiration must be inorganic substances.
A. only (I) in true
B. only (II) is true
C. both (I) and (II) are true
D. neither (I) nor (II) is true

30. Which term infers specifically biosynthesis?
A. metabolism
B. anabolism
C. catabolism

31. The biosynthesis of which of the following would follow the purine pathway?
A. ATP
B. TTP
C. GTP
D. ATP and TTP
E. ATP and GTP

32. Consider a culture medium which contains the following: glucose, yeast extract, hydrolyzed casein, minerals, and water. The source of energy is
A. glucose
B. yeast extract
C. hydrolyzed casein

33. Nutrient agar is an example of a
A. selective medium
B. synthetic medium
C. complex medium
D. tissue culture medium

34. Yeast represents a good example of a facultative aerobe. Given this statement, which of the following statements are true?
A. Yeast will grow anaerobically by fermentation.
B. Yeast will grow aerobically by respiration.
C. A greater cell yield will be obtained under aerobic conditions than under anaerobiosis.
D. (B) and (C)
E. (A), (B), and(C).

35. The most common high-energy phosphate compound is phosphoenol pyruvate, which serves as the prime energy carrier in the cell.
True
False

36.  The reduction of pyruvate to lactate by yeast is an example of anaerobic respiration.
True
False

37. The greatest value of the enrichment culture technique is that it has led to an appreciation of the diversity of the microbial world.
True
False

38. The growth of a population of bacteria is plotted on Cartesian graph paper. The growth curve will be:
A. linear
B. sigmoid
C. hyperbolic
D. exponential

39. The growth of a population of bacteria is plotted on semi-logarithmic graph paper. The growth curve will be:
A. linear
B. sigmoid
C. hyperbolic
D. exponential

40. The growth of a bacterial population is plotted on semi-logarithmic graph paper. The rate of growth is indicated by:
A. the length of the line
B. the slope of the line
C. the height of the line
D. none of the above.

41. The time required for the formation of two cells from one cell is called
A. the generation time
B. the doubling time
C. the growth rate
D. (A) or (B)
E. (A), (B), or (C)

42. The total cell count of a bacterial population may be measured by
A. the spread plate method
B. the pour plate method
C. direct microscopic count
D. optical density of broth
E. (A) and (B)

43. A viable cell count of a bacterial population is obtained by
A. the spread plate method
B. the pour plate method
C. direct microscopic count
D. optical density of broth
E. (A) or (B)

44. Given: A population of bacteria with an initial population of 5 x 10⁷, and a final population of 10⁸ after an incubation of 30 minutes. What is the doubling time for this culture?
A. 0.5 hours
B. 1.0 hours
C. 2.0 hours
D. 5.0 hours

45. The term "Colony forming unit (CFU)" is preferable to viable cell when scouring a viable plate count since
A. all viable cells will form a colony
B. all viable cells may not form a colony
C. a colony may have arisen from more than one viable cell
D. non-viable cells may also form colonies
E. (B) and (C)

46. Which of the following RNAs is the most prevalent (by weight) in the bacterial cell?
A. mRNA
B. rRNA
C. tRNA

47. The usual type of microorganism used in the teaching laboratory would be classified in which group based on its temperature for optimum growth?
A. psychrophile
B. mesophile
C. thermophile
D. extreme thermophile
E. psychrotolerant

48. A marine bacterium has been isolated, and its requirement for the marine environment verified. The microbe is called
A. an osmophile
B. a halophile
C. a xerophile

49. Which of the following enzymes destroys hydrogen peroxide?
A. catalase
B. superoxide dismutase
C. peroxidase
D. (A ) and (B)
E. (A) and (C)

50. During stationary phase of growth of bacteria, no cell division will occur.
True
False

51. The most difficult problem in sterilization is to kill
A. vegetative cells of bacteria
B. bacterial endospores
C. Archaea
D. microcysts
E. fungi

52. The code for an amino acid must contain how many nucleotide bases?
A. one
B. two
C. three
D. four
E. twenty

53. Supercoiling of DNA is induced by
A. DNA polymerase
B. DNA endonuclease
C. topoisomerase II (DNA gyrase)
D. topoisomerase I

54. The minimum number of nucleotide bases on a strand of DNA required to code for a polypeptide consisting of 150 amino acids would be
A. 50
B. 150
C. 300
D. 450
E. 600

55. The ratio of G to C in cellular DNA is
A. 1:1
B. 2:1
C. 4:1
D. varies with the cell type

56. 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
D. a DNA starter sequence with a free 5'-OH

57. Nonchromosomal genetic elements which may be found in a prokaryotic cell include
A. viruses
B. plasmids
C. mitochondrial DNA
D. (A) and (B)
E. (A), (B), and (C)

58. Which form of RNA is the smallest?
A. mRNA
B. rRNA
C. tRNA
D. viral RNA

59. Promoter sequences of Escherichia coli have been studied in great detail. Which of the following statements does not apply to these promoters?
A. One sequence that has been identified is at the -10 region, i.e., before the stare of transcription.
B. A recognition site is present at -35 bases.
C. All promoters have the same sequence at the Pribnow box.
D. (A) and (B)
E. (B) and (C)

60. Consider the RNA polymerase of E. coli. The initiation of RNA synthesis is catalyzed by
A. a simple, monomeric enzyme
B. the core enzyme alone
C. the core enzyme plus sigma factor
D. the core enzyme, sigma factor, and the promoter

61. tRNA binds mRNA by the
A. D-loop
B. acceptor stem
C. anticodon loop
D. T-loop

62. The ribosome binding site in mRNA is
A. upstream of the initiation codon
B. called the Shine-Delgardo sequence
C. able to recognize the small ribosomal subunit
D. functions in all of the above
E. function in none of the above

63. If the codon for phenylalanine in mRNA is UUU, then the corresponding sequence on the nonsense strand of DNA would be
A. TTT
B. AAA
C. GGG
D. CCC
E. UUU

64. The key link between codon and the corresponding amino acid is
A. DNA
B. mRNA
C. rRNA
D. tRNA

65. Which of the following is not characteristic of DNA polymerase?
A. replication proceed 5'3'
B. addition of nucleotides is to the growing end of the chain
C. constructing a new chain can be done de novo
D. 3'5' exonuclease activity is present

66. The amino acid serine is coded by the triplets, UCU, UCC, UCG, and UCA. This is an example of
A. the universality of the genetic code
B. degeneracy in the genetic code
C. unambiguity in the genetic code
D. nonsensical codons

67. Possible consequences of catabolite repression include
A. diauxic growth in the presence of two energy sources
B. repression even in the presence of an appropriate inducer
C. both (A) and (B)
D. neither (A) nor (B)

68. A series of genes which are all regulated by one operator is call
A. an operator
B. a repressor
C. an exon
D. an intro
E. an operon

69. A bacteriophage is a
A. host phagocyte that ingests bacteria
B. bacterium that digests other bacteria
C. host antibody that lyses bacteria
D. bacterial virus

70. The latent period of viral infection is the
A. eclipse period
B. adsorption period
C. adsorption period plus the eclipse period
E. period from adsorption to host-cell lysis

71. Which of the following is not a characteristic of bacteriophage T4?
A. a large icosahedral head
B. a complex tail (helical tube with sheath, "neck," and collar")
C. endplate with jointed tail fibers
D. a unique base, 5-hydroxymethylcytosine
E. double-stranded RNA

72. The genetic material of viruses during their life cycle may be
A. DNA
B. RNA
C. DNA and RNA
D. (A) or (B)
E. (A), (B), or (C)

73. Retroviruses contain an RNA genome in the virion, but a DNA intermediate is involved in replication.
True
False

74.  Some viruses change normal cells to a cancerous cell by a process termed transformation.
True
False

75. A mutant bacterium requires that an amino acid must be added to a growth medium which supports the wild-type parental strain in order for the mutant strain to grow. This mutant is an example of
A. an autotroph
B. an auxotroph
C. a prototroph
D. a heterotroph
E. an organotropy

76. Consider a mutation in which causes a change in the mRNA from UAC to UAU, where both triplets specify the amino acid tyrosine. Which of the following terms may be used to describe the event which occurred?
A. a silent mutation
B. a nonsense mutation
C. a missense mutation
D. a point mutation
E. (A) and (D)

77. A mutation has occurred which is readily reversible to restore the original parental type. This is most likely due to
A. a deletion
B. an insertion
C. a point mutation
D. a frame-shift mutation
E. any of the above

78. DNA fragments may be introduced into a recipient by which of the following methods?
A. transformation
B. transduction
C. conjugation
D. any one of the above

79. Terms must be matched correctly! The terms
1. transformation,
2. transduction,
3. conjugation;
and the means whereby DNA is transferred
a. cell-to-cell contact
b. via bacteriophage
c. as a free molecule
ANSWERS:
A. 1a,2b,3c
B. 1b,2c,3a
C. 1c,2a,3b
D. 1c,2b,3a
E. 1b,2a,3c

80. Drug resistance among pathogenic bacteria is spread most rapidly through
A. selection of mutants
B. bacteriophage
C. conjugative plasmids

81. The position of genes on a genetic map, as that shown for E. coli in our textbook are designated in what unit?
A. degrees
B. nanometers
C. centamorgans
D. minutes
E. millimeters

82. Consider the consequences of an F⁺ x F^- mating. Which of the following apply?
A. recipients become F⁺
B. chromosomal genes are always transferred
C. a plasmid is involved
D. (A) and (C)
E. (A), (B), and (C)

83. (I) The F plasmid of E. coli is about 95 kb, and is present in F⁺ and F^- strains. (II) The F plasmid is conjugative.
A. only (I) in true
B. only (II) is true
C. both (I) and (II) are true
D. neither (I) nor (II) is true

84. Hfr strains of E. coli
A. do not possess an F factor
B. have the F factor as a plasmid
C. have an F factor integrated into the chromosome
D. transfer the F factor to other strains at high frequency

85. All Hfr strains possess an F factor integrated into the same chromosomal locus.
True
False

86. Conjugative plasmids have the capacity to transfer themselves from cell to cell by contact.
True
False

87. Pasteurization is used on
A. wine
B. beer
C. milk
D. apple juice
E. all of the above

88. Typical conditions for an autoclave include steam at 15 psi, and a temperature of 121°C.
True
False

89. Food often makes a good substrate for bacterial or fungal growth.
True
False

90. T F All bacteriostatic agents can be used to kill fungi.
True
False

91. Which of the following does not occur in anoxygenic photosynthesis?
A. the system operates under anaerobic conditions
B. water is split into oxidizing and reducing parts
C. ATP is formed via cyclic photophosphorylation
D. bacteriochlorophyll is involved in the light reaction

92. Consider chlorophyll a, the principle chlorophyll of most algae and of cyanobacteria. Which of these statements are true?
A. it absorbs green light
B. it absorbs red and blue light
C. it transmits green light
D. it contains phytol, a cyclopentanone ring, and iron
E. (B) and (C)

93. Consider the genus Pseudomonas. Which of the following apply to at least some member of this group?
A. fluorescent pigments
B. polar flagella
C. animal pathogens
D. plant pathogens
E. any of the above

94. The usual method for protozoa to obtain food is by
A. autotrophy
B. phagotrophy
C. phototrophy

95. Members of which of the following protozoan groups may cause infectious disease in humans?
A. Mastigophora
B. Sarcodina
C. Ciliophora
D. Sporozoa
E. all of the above

96. Fungal spores are always diploid.
True
False

97. Consider the growth curve for a typical bacterium growing in broth. During which phase of the growth cycle are essentially all cells viable?
A. lag
B. exponential
C. stationary
D. death

98. Of the following, the best description of the rickettsiae and chlamydia is as
A. pathogens
B. fastidious organisms
C. obligate intracellular parasites
D. obligate intercellular parasites.

99. You are studying an anaerobic organism. Which of the following pathways would you expect to be carried out in this organism?
A. the citric acid (TCA) cycle
B. glycolysis
C. oxidative phosphorylation
D. (A) and (B)
E. (A) and (C)

100. The aerobic bacterium Pseudomonas aeruginosa is fed glucose and the products from the bacterial respiration are measured. You would expect to find the following products of respiration.
A. CO₂
B. ATP
C. H₂O
D. all of the above

Part II: Matching. Match the term with the best identifier. All identifiers may not be used. None will be used more than once! Be sure to choose the most specific identifier. Two points each.
_____ 101. Established the germ theory of disease.
_____ 102. Reported his microscopic observation of bacteria to the Royal Society.
_____ 103. Developed a vaccine for rabies.
_____ 104. Protected people from smallpox by infecting them with cowpox.
_____ 105. Made up of amino acids held together with peptide bonds.
_____ 106. These compounds are made up of a glycerol molecule attached to one, two, or three long-chain fatty acids.
_____ 107. These compounds are structural components of chromosomes where they carry the genetic information and direct its expression.
_____ 108. A reaction in the Citric Acid (TCA) Cycle
_____ 109. A reaction in glycolysis
_____ 110. Heated steam under pressure.
_____ 111. To make free from all life.
_____ 112. A substance that temporarily prevents multiplication of bacteria.
_____ 113. A substance that removes pathogens from table tops.
_____ 114. A substance that kills bacteria.
_____ 115. A substance that kills viruses.
A. Disinfectant
B. Viricidal agent
C. Iodophor
D. Aseptic
E. van Leeuwenhoek
F. Sanitize
G. Sterilize
H. Bactericidal agent
I. Bacteriostatic agent
J. Cavitation
K. Edward Jenner
L. Autoclave
M. Filtration
N. Tyndallization
O. John Snow
P. Citric Acid [alpha]-ketoglutaric acid.
Q. Glucose glucose-6-PO₄
R. Fatty acid acetyl-CoA
S. Carbohydrates
T. Lipids
U. Proteins
V. Nucleic Acids
W. Louis Pasteur
X. Robert Koch
Y. Emil von Behring
Z. Frau Hesse

Part III. Diagrams. Complete or supply the diagram as requested.
116. (10 points). Complete the diagram below to illustrate an inducible operon when the inducer is present.
^{------------------}PROMOTE^-----OPERATOR^-----STRUCTURAL GENES^-----------

117. (10 points) Draw and label the cellular envelope of a Gram- Bacterium.