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Problem 2.4a
The optimum pH of Acidithiobacillus bacteria (pH 3) is _______________ times more acid than blood (pH 7).
a. 4
b. 10
c. 100
d. 1000
e. 10,000
Problem 6.10a
NAME IT A prokaryotic cell hitched a ride to Earth on a space shuttle from some unknown planet. The organism is a psychrophile, an obligate halophile, and an obligate aerobe. Based on the characteristics of the microbe, describe the planet.
Problem 6.1a
Use the following information to answer questions 1 and 2. Two culture media were inoculated with four different bacteria. After incubation, the following results were obtained:
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Medium 1 is
a. selective.
b. differential.
c. both selective and differential.
Problem 6.2a
Use the following information to answer questions 1 and 2. Two culture media were inoculated with four different bacteria. After incubation, the following results were obtained:
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Medium 2 is
a. selective.
b. differential.
c. both selective and differential.
Problem 6.4a
Seven methods of measuring microbial growth were explained in this chapter. Categorize each as either a direct or an indirect method.
Problem 6.5a
By deep-freezing, bacteria can be stored without harm for extended periods. Why do refrigeration and freezing preserve foods?
Problem 6.7a
Nitrogen and phosphorus added to beaches following an oil spill encourage the growth of natural oil-degrading bacteria. Explain why the bacteria do not grow if nitrogen and phosphorus are not added.
Problem 6.7a
Which one of the following temperatures would most likely kill a mesophile?
a. -50℃
b. 0℃
c. 9℃
d. 37℃
e. 60℃
Problem 6.8a
Differentiate complex and chemically defined media.
Problem 6.9a
Which of the following is true about the optimum growth temperature of most mesophiles?
a) They can grow well at 37^0C.
b) They are more likely to grow at refrigerator temperatures.
c) They can strive well in extremely high temperatures.
d) All of the above.
Problem 6.9a
Which of the following types of media would not be used to culture aerobes?
a. selective media
b. reducing media
c. enrichment media
d. differential media
e. complex media
Problem 7.1a
The thermal death time for a suspension of Bacillus subtilis endospores is in dry heat and less than in an autoclave. Which type of heat is more effective? Why?
Problem 7.2a
If pasteurization does not achieve sterilization, why is pasteurization used to treat food?
Problem 7.3a
Thermal death point is not considered an accurate measure of the effectiveness of heat sterilization. List three factors that can alter thermal death point.
Problem 7.4a
The antimicrobial effect of gamma radiation is due to (a) ________. The antimicrobial effect of ultraviolet radiation is due to (b) ________.
Problem 12.2a
A mixed culture of Escherichia coli and Penicillium chrysogenum is inoculated onto the following culture media. On which medium would you expect each to grow? Why?
a. 0.5% peptone in tap water
b. 10% glucose in tap water
Problem 12.5a
Differentiate cellular and plasmodial slime molds. How does each survive adverse environmental conditions?
Problem 24.4a
Match the following choices to the culture descriptions in questions 3 through 6:
a. Chlamydia
b. Coccidioides
c. Histoplasma
d. Mycobacterium
e. Mycoplasma
This pneumonia etiology requires cell culture.
Problem 24.5a
Match the following choices to the culture descriptions in questions 3 through 6:
a. Chlamydia
b. Coccidioides
c. Histoplasma
d. Mycobacterium
e. Mycoplasma
Microscopic examination of a lung biopsy shows ovoid cells in alveolar macrophages. You suspect these are the cause of the patient’s signs and symptoms, but your culture grows a filamentous organism.
Problem 24.6a
Match the following choices to the culture descriptions in questions 3 through 6:
a. Chlamydia
b. Coccidioides
c. Histoplasma
d. Mycobacterium
e. Mycoplasma
Microscopic examination of a lung biopsy shows spherules.
Problem 28.2a
Acetobacter is necessary for only one of the steps of vitamin C manufacture. The easiest way to accomplish this step would be to
a. add substrate and Acetobacter to a test tube.
b. affix Acetobacter to a surface and run substrate over it.
c. add substrate and Acetobacter to a bioreactor.
d. find an alternative to this step.
e. none of the above
Problem 28.9a
DRAW IT Label the trophophase and idiophase in this graph. Indicate when primary and secondary metabolites are formed.
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