1.
2. Which is most abundant and active in divisome complexes? a. FtsZ b. DNA replication forks c. MinCD d. MreB
2.
3. The process by which two cells arise from one is known as a. Conjugation b. Binary fission c. Meiosis d. Mitosis
3.
4. A bacterium that lacks the MreB gene will have a ____ shape a. Bacillus b. Coccoid c. Short bacillus d. Vibrio
4.
5. The time interval required for the formation of two cells from one is called the a. Generation time b. Growth time c. Growth rate d. Division rate
5.
6. Enumerating cells in a biofilm is especially challenging for a. Microscopic direct counting b. Measuring turbidity c. Viability counts with spread plating d. Microscopic direct county, measuring turbidity, and viability counts with spread plating
6.
7. The time between inoculation and the beginning of growth is usually called the a. Lag phase b. Log phase c. Dormant phase d. Death phase
7.
8. Optical density and viable cell concentration are
LEAST proportional to each other during a. Lag phase b. Exponential growth phase c. Stationary phase d. Death phase
8.
9. To determine viable cell counts of a heat-sensitive bacterial isolate, which cell counting method would be best to avoid? a. Spread-plate method b. Pour-plate method c. Live staining and direct counting with a microscope d. Both spread- and pour-plate methods
A
B
B
A
D
A
D
B
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9.
10. Bacteria that are able to grow in humans and cause disease have likely evolved to be a. Psychrophiles b. Mesophiles c. Theromphiles d. Hyperthermophiles
10.
11. Where would it be best to isolate bacteria from to study the mechanism of the sodium motive force? a. Human gut b. Hot springs c. Soda lakes d. Volcanoes
11.
12. An agar plate for counting colonies and maximizing statistical validity should ideally contain a. 1 to 100 colonies b. 50 to 100 colonies c. 30 to 300 colonies d. 100 to 1000 colonies
12.
14. The number of colonies obtained in a plate count does not depend on the a. Inoculum volume b. Size of the colonies c. Type of culture medium d. Incubation time
13.
15. Cell density in a chemostat is controlled by a. The concentration of the limiting nutrient b. The dilution factor c. The size of the initial inoculum d. The concentration of the limiting nutrient, the dilution factor, and the size of the initial inoculum
14.
16. In which type of culture(s) does one find a closed system? a. Chemostat cultures b. Continuous culture c. Batch culture d. All of the above
15.
17. For most physiological experiments, it is usually most desirable for cells to be in the a. Exponential phase b. Stationary phase c. Lag phase d. Death phase
16.
18. The cardinal temperatures are the a. Minimum, optimum, and maximum temperatures taken together b. Maximum temperatures c. Minimum temperatures d. Optimum temperatures
B
C
C
B
A
C
A
A

17.
19. The usual temperature range for most organisms is about a. 30-40 degrees C b. 60 degrees C c. 20 degrees C d. 10 degrees C
18.
20. The cytoplasmic membrane must be in a(n) ____ state for proper functioning a. neutral b. stable c. fluid d. elastic
19.
21. A microbe growing in a functioning refrigerator is probably a a. psychrophile b. thermophile c. mesophile d. hyperthermophile
20.
22. Consider solution A, with a pH of 6, and solution B, with a pH of 9 a. solution A is 3 times more acidic than solution B b. solution B is 1000 times more alkaline (basic) than solution A c. solution B is 3000 times more alkaline (basic) than solution A d. solution A is 30 times more acidic than solution
21.
23. Thermal environments around hot springs are conductive to the growth of a. chemolitotrophs b. chemoorganotrophs c. both chemoorganotrophs and chemolithotrophs d. neither chemoorganotrophs nor chemolitotrophs
22.
24. Which of these statements is/are true? a. The most thermophilic prokaryotes are species of
Archaea b. Nonphototrophic organisms are able to grow at higher temperatures than phototrophic organisms c. In general, prokaryotic organisms can grow at higher temperatures than eukaryotic organisms d. All of the above are true
23.
25. As a group, which organisms tend to be most acidtolerant? a. Fungi b. Bacteria c. Archaea d. Protists
24.
26. The ratio of the vapor pressure of the air in equilibrium with a substance to the vapor pressure of pure water is known as a. Osmosis b. Positive water balance c. Water activity d. Vapor activity
A
B
A
B
C
D
A
C
25.
27. Organisms able to live in environments with high sugar concentrations are a. Xerophiles b. Osmophiles c. Halotolerant d. Anaerobic fermenting bacteria
26.
28. When water activity is low, an organism must a. Increase its internal solute concentrations b. Increase its external solute concentration c. Decrease its internal solute concentration d. Decrease its external solute concentration
27.
29. A bacterium containing ____ provided with hydrogen peroxide will produce oxygen bubbles a. Catalase b. Superoxide dismutase c. Superoxide reductase d. Peroxidase
28.
30) By controlling the concentration of nutrients continuously added to a chemostat, cells can constantly be maintained at the
A) exponential growth phase.
B) stationary growth phase.
C) lag growth phase.
D) death growth phase.
29.
31. Which of the following forms of oxygen is/are generally toxic to living organisms? a. Superoxide anion b. Hydrogen peroxide c. Hydroxyl radical d. All of the above
30.
33. Which of the following methods to enumerate cells often requires specialized staining to observe nonpigmented bacteria? a. Spectrophotometry/tubidity b. Spread-plating c. Microscopy d. Spread-plating, turbidity, and microscopy
31.
34. To determine the specific growth rate of a bacterial population, it is essential to know a. Cell concentrations at varied time points b. Total number of cells in the population at varied time points c. Cell concentrations at varied time points or the generation time d. Turbidity measurements and the total number of cells in the population at varied time points
32.
35. The partition that is a result of the inward growth of the cytoplasmic membrane and cell wall from opposing directions is known as the a. Divisome b. Septum c. Autolysin d. Colony
B
A
A
A
D
C
A
B

33.
36. Which term is most relevant in describing the efficacy of an antimicrobial for use in a clinical setting? a. Effective dose b. Sterilization coefficient c. Lethal dosage d. Minimum inhibitory concentration
34.
37. In general, which group is most resistant to radiation? a. Microscopic fungi b. Viruses c. Thermotolerant bacteria d. Spore-forming bacteria
35.
38. What is the function of bactoprenol? a. It is a hydrophobic alcohol that transports peptidoglycan precursors across the cytoplasmic membrane b. It is responsible for forming the peptide cross-links between muramic acid residues in adjacent glycan chains c. It triggers the recruitment of FtsZ and the initiation of the divisome d. It supplies the energy necessary for transpeptidation to occur
36.
41. One laboratory group repeated the same experiment described by others with the identical bacterial isolate and the same growth medium and conditions used but were unable to achience the same
OD at 600nm. What is the least likely cause for this discrepancy of turbidity measured? a. One lab used 16mm wide test tubes and the other used 18 mm wide test tubes b. One labe subtracted the yellow color of the growth medium away from the final turbidity reported whereas the other lab used colorless water. c. One lab vigorously dispersed the biofilm-forming bacteria with vortexing and the other did not d. The two labs varied with 1000 m elevation and did not consider the influence of pressure
37.
42. A drug targeting _____ would NOT be an effective antibiotic. a. ZipA b. FtsI c. MreB d. Transpeptidation
38.
43. An antiseptic (or germicide) is distinguished from other sterilizing compounds by a. Being able to inhibit growth of microorganisms but not necessarily kill all of them b. Being able to be used on living tissues without harm c. Its ability to protect from subsequent microbial infections—not just initial sterilization d. Killing all bacteria and microscopic fungi but not being effective against viruses
D
D
A
D
D
B
39.
44. Growing bacteria that degrade an environmental pollutant, which is also toxic to the cells at artificially high concentrations, might require ___ to obtain a sufficient population for biochemistry studies. a. A continuous batch culture b. A second growth substrate to keep the culture in exponential growth phase c. Steady state growth kinetics d. The use of a chemostat
40.
A ________ agent is a chemical that inhibits bacteria from reproducing, but does NOT necessarily kill them.
A) bacteriostatic
B) bacteriolytic
C) bacteriocidal
D) xerophilic
41.
Bacterial growth refers to
A) an increase in the number of cells.
B) the occurrence of binary fission.
C) the time required for one cell to divide into two.
D) the occurrence of mitosis.
42.
The cell membranes of thermophiles and hyperthermophilic bacteria typically have
A) more saturated fatty acids.
B) more long chain fatty acids.
C) fewer unsaturated fatty acids.
D) All of these answer choices are true of thermophiles and hyperthermophilic bacteria.
43.
A chemical that denatures proteins is most likely to be classified as a(n) ________ agent.
A) antiseptic
B) bacteriostatic
C) bacteriocidal
D) detergent
44.
A common antimicrobial chemical (or chemicals) used as both an antiseptic and a general disinfectant is
A) iodophors.
B) 70% alcohol.
C) hydrogen peroxide.
D) Each of these chemicals at appropriate concentrations can be used as antiseptics or disinfectants.
45.
Cultures of a bacterial species were incubated on the shelf of a refrigerator (5°C), on a lab benchtop (25°C), on the shelf of a 37°C incubator, and on the shelf of a
50°C incubator. After incubation, there was no growth at 37°C or 50°C, slight growth on the benchtop, and abundant growth at refrigeration. What term could be used for this species?
A) halophile
B) mesophile
C) anaerobe
D) psychrophile
D
A
A
D
C
D
D

46.
A halotolerant facultative anaerobe would grow BEST in which of the following environments?
A) oxygen depleted saline
B) oxygenated saline
C) oxygen depleted non-saline
D) oxygenated non-saline
47.
A medium containing known substances in precise amounts is known as a ________ media.
A) selective
B) complex
C) natural
D) defined
48.
A microbe growing in a refrigerator is likely
A) psychrophilic.
B) mesophilic.
C) psychrotolerant or psychrophilic.
D) hyperthermophilic.
49.
Microbial contamination is prevented by the
A) use of the quadrant streak method.
B) use of aseptic technique.
C) use of cultures containing special nutrients.
D) spread plate method.
50.
Most mesophilic organisms can grow in a temperature range of
A) 0-15°C.
B) 10-20°C.
C) 20-45°C.
D) 50-65°C.
51.
Obligate anaerobes which are sensitive to O2 would be found growing
A) throughout a tube of thioglycolate broth.
B) only at the very top of a tube of thioglycolate broth.
C) only at the bottom of a tube of thioglycolate broth.
D) approximately one-third of the way down the thioglycolate broth.
52.
The optimal growth temperature of a bacterium is most closely related to the optimal temperature for
A) transcription of DNA.
B) DNA replication.
C) enzyme function.
D) mRNA attachment to ribosomes.
53.
Relative to enzymes in mesophilic microorganisms, which of the following is NOT characteristic of enzymes in psychrophiles?
A) decreased alpha helix content
B) decreased beta sheet content
C) fewer hydrogen bonds
D) fewer ionic bonds
D
D
C
A
C
C
C
A
54.
Selective medium differs from differential medium because
A) selective medium permits growth of more organisms than differential medium.
B) selective medium permits growth of a particular microbial type while differential medium is used to distinguish between types of organisms.
C) differential medium differentiates pathogens from nonpathogens while selective medium grows only pathogens.
D) differential medium contains growth inhibitors while selective medium does not.
55.
Serial dilutions are generally made
A) when the appropriate viable count is unknown.
B) based on powers of 10, although other serial dilution factors are possible.
C) to reach a suitable dilution while minimizing error.
D) All of these answer choices apply.
56.
Superoxide dismutase and catalase work together to convert superoxide into
A) peroxide.
B) oxygen.
C) water
D) water and oxygen
57.
t/f A bacterial cell in nutrient broth with a generation time of 15 minutes will produce 16 cells in 2 hours.
58.
T/F A bacterium's pH optimum reflects the optimal pH of its intracellular environment
59.
T/F A bacterium such as a snow alga that is able to suvive in cold temperature is called a psychrophile.
60.
t/f A bacterium whose optimal growth temperature is
35 C would be classified as a thermophile.
61.
t/f A complex medium is one that has been completely made in the laboratory and the concentration of all the nutrients is known.
62.
T/F A non-aerated or shaken liquid growth medium inoculated with a bacterium is one of the best ways to culture an obligate anaerobe.
63.
T/F An unpressurized autoclave would not be able to sterilize a growth medium with contaminating bacteria but could still pasteurize it.
64.
t/f A selective medium is used to suppress the growth of certain bacteria in order to facilitate the growth of other bacteria.
65.
t/f Autoclaving and pasteurization are two processes that are both very effective for sterilization.
66.
t/f Based on studies with obligate acidophiles, high concentrations of hydrogen ions are required for their membrane stability.
B
D
D
F
F
T
F
F
F
T
F
F
T

67.
T/F By using a stain living cells only, microscopy would be a better approach to enumerate the number of living cells in a soil sample compared to viability counts of serially diluted soil.
68.
T/F Counting chambers are used for estimating the number of cells present in a liquid culture
69.
T/F Direct microscope counting of stained cells is an accurate method for calculating the exact number of cells in a sample
70.
t/f Direct microscopic counting of cells is an accurate method for estimating the number of viable cells in a sample.
71.
T/F Due to the relationship between the rate of enzyme catalysis and temperature, organisms living in boiling hot springs are also rapid growers with fast doubling times.
72.
T/F During elongation of a cell during binary fission, small gaps caused by transglycosylases are formed before cell membrane precursors can be inserted.
73.
T/F For most purposes of studying bacterial isolates, viable counting usually gives accurate information about the number of active cells present in a culture volume
T
T
T
F
F
F
T
74.
T/F Generation of new bacillus-shaped cells starts with one cell elongating and terminates when split into two separate bacilli.
75.
T/F Heterotrophic bacteria will run out of organic growth substrates in batch cultures but chemostats can provide constant nutrient source for them to grow.
Chemostats for photoautotrophic bacteria are not necessary to maintain them at a constant growth phase because a light can artificially be turned on constantly.
76.
T/F Identifying bactoprenol inside the rare bacteria that lack peptidoglycan would be unexpected considering its role in membrane biosynthesis.
77.
T/F In a chemostat, growth rate and growth yield can be controlled independently
78.
T/F In both lag and stationary phase, there is not net increase or decrease in viable cells.
79.
T/F In fast-growing Escherichia coli cells, multiple replication forks of genomic DNA allows binary fission to occur before the genome has been fully duplicated.
T
F
T
T
T
F
80.
T/F In principle, the chemical composition of membranes in obligate acidophiles could be distinguished from neutrophils.
81.
t/f Knowledge of microbial growth patterns is useful in working with the control of microbial growth.
T
T
82.
t/f Many fungi and bacteria grow best at pH 5 or below. T
83.
t/f Mesophiles typically have longer fatty acid tails and more saturated carbon-carbon bonds in their cytoplasmic tails compared with thermophiles.
84.
T/F Microbial growth is generally described as the increased number of cells rather than the expanding size of an individual cell.
85.
t/f Most microorganisms are particularly susceptible to antimicrobial agents during the logarithmic growth phase.
86.
T/F One reason food is refrigerated to control microbial growth is because irreversible cell damage is more likely to occur at low rather than high temperatures.
87.
t/f Organisms living in boiling hot springs often grow rapidly and have short doubling times.
88.
t/f Planktonic cells remain in suspension while sessile cells adhere to a surface.
89.
T/F Some microbes can grow in boiling water.
90.
T/F Sterility of a laminar flow hood is accomplished by filter-sterilized air passed through the hood quickly enough that non-sterile air does not flow into the work area.
91.
T/F Taq polymerase was isolated from a thermophile and is used in the polymerase chain reaction (PCR) technique because it does not become inactivated at high temperatures.
92.
T/F The activity of MinC and MinD direct whether a bacterial cell will be coccoid or bacillus shaped.
93.
T/F The death phase applies to individual cells rather than populations
94.
T/F The duration of logarithmic growth would increase if bacterial cells divided into three equal daughter cells rather than two
95.
T/F The lag phase does NOT occur if all the cells in the culture are viable.
96.
t/f The lag phase does NOT occur if an exponentially growing culture is transferred into a nutrient rich medium with the same components and growth conditions as the previous medium.
97.
T/F The optimum temperature is usually closer to the minimum temperature than the maximum temperature.
98.
T/F The rates of expontial growth vary greatly according to the bacterial species as well as the bioavailable nutrients.
99.
T/F The sensitivity of DNA and RNA is one major reason water activity can limit microbial growth.
100.
t/f The thermal death time is the time needed to kill all the bacteria in a particular culture at a certain temperature.
F
T
T
F
T
T
T
T
T
F
F
F
F
T
F
T
F
T

101.
T/F When viable cell concentrations are too high to count on an agar medium, it is most common to use larger sized plates to increase the surface area for counting the colonies
102.
The time between inoculation and the beginning of growth is usually called the
A) lag phase.
B) log phase.
C) dormant phase.
D) death phase.
103.
Turbidity measurements are commonly utilized for monitoring
A) planktonic cultures.
B) biofilms.
C) conies.
D) sessile cultures.
104.
The use of chemical agents directly on exposed body surfaces to destroy or inhibit vegetative pathogens is
A) disinfection.
B) sterilization.
C) antisepsis.
D) sanitization.
105.
What temperature is most commonly used in autoclaves to sterilize growth media and other devices prior to experimentation?
A) 95°C
B) 101°C
C) 121°C
D) 140°C
106.
When counting colonies on an agar plate
A) it is assumed that each colony arose from division of one or a few cells.
B) only viable colonies are counted.
C) the medium must be suitable for colony growth.
D) All of these answer choices are true.
107.
Which method would be LEAST effective at sterilizing a glass hockey stick to use in the spread-plate method?
A) autoclaving
B) gamma radiation
C) ethanol soaking
D) ultrahigh-temperature pasteurization
108.
Which of the following is/are transferred to daughter cells during cell division? a. Genomic DNA, the blueprint for everything the cell needs b. Individual genes and enzymes to later be brought together to form the genome c. Chromosome and enzymes to immediately begin cellular metabolism d. Chromosome, proteins, and all other cellular constituents
F
A
A
C
C
A
D
D
109.
Which of the following statements is FALSE?
A) In the death phase, bacterial growth may cease as a result of oxygen and nutrient depletion.
B) The generation time of bacteria may vary from species to species.
C) Bacteria typically divide by binary fission, producing two daughter cells.
D) In the lag phase, cell death exceeds cell division.
110.
Which of the following statements is TRUE of disinfectants?
A) They are always effective in destroying endospores.
B) They are used on living tissue.
C) They are used for sterilization.
D) They are used on inanimate surfaces.
111.
Why is the enzyme catalase important to the survival of bacteria?
A) Catalase protects the cell from desiccation.
B) Catalase breaks down toxic hydrogen peroxide.
C) Catalase allows for growth in high salt concentrations.
D) Catalase aids in the transport of oxygen into the cell.
D
D
B