Microbiology: An Introduction
11th Edition
ISBN: 9780321733603
Author: Gerard J. Tortora, Berdell R. Funke, Christine L. Case
Publisher: Benjamin Cummings
expand_more
expand_more
format_list_bulleted
Textbook Question
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?
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solutionStudents have asked these similar questions
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)
a)
1
1
b)
5
4
c)
1
2
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
Additional Science Textbook Solutions
Find more solutions based on key concepts
Problem Set
True or False? Indicate whether each of the following statements about membrane transport is true (...
Becker's World of the Cell (9th Edition)
Define histology.
Fundamentals of Anatomy & Physiology (11th Edition)
Describe the evolution of mammals, tracing their synapsid lineage from early amniote ancestors to true mammals....
LooseLeaf for Integrated Principles of Zoology
CAUTION How can evolutionary fitness be estimated? a. Document how long individuals survive. b. Count the numbe...
Biological Science (6th Edition)
Explain why hyperthermophiles do not cause disease in humans.
Microbiology with Diseases by Taxonomy (5th Edition)
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.Similar questions
- A batch of turkey rolls (10 lb—approximately 4.5 Kg—each) were cooked to 165°F internal temperature in bags, opened, sliced, vacuum-packaged, and stored at 40°F. The product was expected to have a refrigerated shelf life of 50 days. However, after 40 days, the packages contained gas and approximately 107 bacterial cells/g of meat. The bacterial species involved in the spoilage was found to be Leuconostoc carnosum, which is killed at 165°F. What could be the sources of the bacterial species in this cooked product?arrow_forwardWhat is the amount (mL) of pre-culture (108 cell/mL) necessary to inoculate (to add) in a 2-liter culture media for a concentration of 6.5 x 106 cells/mL?arrow_forwardErysipelothrix rhusiopathiae is a gram positive bacilli that survives in water contaminated by a sick animal’s feces or urine, soil, or plant material. It is known for causing zoonoses, and is typically associated with occupational exposure to animals. There are a few tests commonly used that help to differentiate the organism. Indicate the results for the following reactions: Catalase: TSI: Growth in gelatin:arrow_forward
- Why do cells need to be kept in the freezing devices first then transferred to liquid nitrogen storage in crypto preservation? In addition, why are antibiotics not used in the cell freezing media? Why FBS concentration higher than 10% (10% is the standard concentration in complete growth media) is recommended in cell freezing media?arrow_forwardNutrient Agar (NA) is a general purpose medium used for the cultivation of a wide variety of non- fastidious microorganisms (Merck, 2000). Its ingredients are listed in Table 2. You are tasked to prepare 300ml of NA, determine the amount of ingredients and write in column 3 in Table 2. Show your calculations. *A sample calculation was made for you. Peptone = 300 ml x 0.5% = 1.5 g Table 2. Medium Composition of Nutrient Agar (NA) with the recommended proportions (Merck, 2019) Ingredients In % In Grams/300ml Peptone 0.5 *1.5 Meat extract 0.3 Agar 1.5 Distilled Water As neededarrow_forwardin a clean, non-sterile 15 mL centrifuge tube, prepare a 2.0% yeast suspension by adding 0.06 g Saccharomyces cerevisiae to 3 mL yeast growing medium (56 mM glucose, 20 mM HEPES, pH 6.8). What percent of yeast suspension is left after a 1:10 dilution?arrow_forward
- The data below were obtained for the growth of a pure culture of Escherichia coli in nutrient broth at a temperature of 37°C. Determine (1) the specific growth rate and (2) generation time of E. coli and the duration of the (3) lag and (4) log (or exponential) phases. (ln 2 = 0.693) Time (h) 0 1 2 3 4 8 16 32 Bacterial No./mL 104.1 103.9 104.4 105.5 106.5 107.7 108.0 107.6arrow_forwardYou spread 0.1 mL volume of a 10^(-6) dilution onto a nutrient agar plate. After 24 hours of incubation at 37°C, there were 280 colonies of bacteria on the plate. A.) What is the original concentration (OCD) of bacteria in the stock sample this dilution came from? B.) Using the OCD value from part A, determine the number of colonies that would be expected to grow on a plate that is inoculated with 0.1 mL volume of 10^(-8) dilution from this same stock of bacteria. Show your work for both.arrow_forwardYou spread 0.1 mL volume of a 10^(-6) dilution onto a nutrient agar plate. After 24 hours of incubation at 37°C, there were 280 colonies of bacteria on the plate. A.) What is the original concentration (OCD) of bacteria in the stock sample this dilution came from? B.) Using the OCD value from part A, determine the number of colonies that would be expected to grow on a plate that is inoculated with 0.1 mL volume of 10^(-8) dilution from this same stock of bacteria.arrow_forward
- The following results were obtained from a disk diffusion test for microbial susceptibility to antibiotics. Staphylococcus aureus was the test organism. Use these data to answer questions. The following results were obtained using the Kirby-Bauer method to assess microbial susceptibility to antibiotics. Staphylococcus aureus was the experimental organism. Use the data below to answer the questions. antibiotics Zone of Inhibition TO 3mm В. 7mm C Omm 10mm The most effective antibiotic was: Select one: O TO B. can't tell O O O O Oarrow_forwardA mistake was made in preparing the arginine decarboxylase test, and mineral oil was NOT added to the test tube after inoculating with bacteria. If an arginine decarboxylase-positive bacteria species was inoculated into the above arginine-decarboxylase broth without mineral oil, what would likely be the color result of this bacteria in this test? Would this produce a false positive or false negative result? Explain.arrow_forwardA disk-diffusion test using E. coli gave the following results: Disinfectant Zone of inhibition (diameter in mm) A 15 B 2.0 C 10 D 5 In the table above, which compound was the most effective against E. coli? A) A B) B C) C D) D E) The answer cannot be determined based on the information provided.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Biochemical Tests-Part 1; Author: Southern Stacker;https://www.youtube.com/watch?v=a-i9vANfQWQ;License: Standard Youtube License