Microbiology: An Introduction
11th Edition
ISBN: 9780321733603
Author: Gerard J. Tortora, Berdell R. Funke, Christine L. Case
Publisher: Benjamin Cummings
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Chapter 7, Problem 4A
To determine the lethal action of microwave radiation, two 105 suspensions of E. coli were prepared. One cell suspension was exposed to microwave radiation while wet, whereas the other was lyophilized (freeze-dried) and then exposed to radiation. The results are shown in the following figure. Dashed lines indicate the temperature of the samples. What is the most likely method of lethal action of microwave radiation? How do you suppose these data might differ for Clostridium?
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You are cultivating Escherichia coli in a chemostat culture. The maximum specific growth rate (µmax) of E. coli that you can reach is known as 1.0 h-1 at your culture conditions. Describe what you would observe for each condition if you have the following settings:
F (flow rate of the fresh medium into the bioreactor vessel) (L/h)
V (Volume of the liquid culture in the bioreactor vessel) (L)
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The nutrient broth is a basic media used for growing a broad variety of microorganisms in the laboratory. The nutrient broth consists mainly of 1.5g * L ^ - 1 extract, 3g * L ^ - 1 yeast extract and 5g * L ^ - 1 sodium chloride dissolved in distilled water. The nutrient agar is prepared by adding the agar at the desired amount into nutrient broth. Answer the following questions. marks)
a) How would you prepare a 500 ml nutrient broth?
b) How would you prepare 2% (w / v) nutrient agar for 1L?
c) How would you prepare a 100 ml nutrient broth supplemented with 100mu * g / m * l ampicillin antibiotic? The stock concentration for ampicillin solution is 100mg / m * l .
Two flasks of E. coli are grown in batch culture in the same medium (2% glucose and amino acids; no nitrate) and at the same temperature (378C). Culture #1 is well aerated. Culture #2 is anoxic. After 16 hours the following observations are made:
■ Culture #1 has a high cell density; the cells appear to be in stationary phase, and the glucose level in the medium is reduced to 1.2%.
■ Culture #2 has a low cell density; the cells appear to be in logarithmic phase, although their doubling time is prolonged (over 1 hour). The glucose level is reduced to 0.2%. Why does culture #2 have so little glucose remaining relative to culture #1, even though culture #2 displayed slower growth and has less biomass?
Chapter 7 Solutions
Microbiology: An Introduction
Ch. 7 - The thermal death time for a suspension of...Ch. 7 - If pasteurization does not achieve sterilization,...Ch. 7 - Thermal death point is not considered an accurate...Ch. 7 - Prob. 4RCh. 7 - DRAW IT A bacterial culture was in log phase in...Ch. 7 - How do autoclaving, hot air, and pasteurization...Ch. 7 - How do salts and sugars preserve foods? Why are...Ch. 7 - Prob. 8RCh. 7 - A large hospital washes burn patients in a...Ch. 7 - Prob. 10R
Ch. 7 - Which of the following does not kill endospores?...Ch. 7 - Which of the following is most effective for...Ch. 7 - Prob. 3MCQCh. 7 - Which of the following cannot be used to sterilize...Ch. 7 - Prob. 5MCQCh. 7 - The data were obtained from a use-dilution test...Ch. 7 - The data were obtained from a use-dilution test...Ch. 7 - Prob. 8MCQCh. 7 - A classmate is trying to determine how a...Ch. 7 - Which of the following is most likely to be...Ch. 7 - Prob. 1ACh. 7 - For each of the following bacteria, explain why it...Ch. 7 - To determine the lethal action of microwave...Ch. 7 - A use-dilution test was used to evaluate two...Ch. 7 - Entamoeba histolytica and Giardia lamblia were...Ch. 7 - Between March 9 and April 12five chronic...Ch. 7 - Prob. 3CAE
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