MICROBIOLOGY-MASTERING MICRO.-ACCESS
11th Edition
ISBN: 9780321802705
Author: Tortora
Publisher: PEARSON
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Chapter 6, Problem 1A
E. coli was incubated with aeration in a nutrient medium containing two carbon sources, and the following growth curve was made from this culture.
- a. Explain what happened at the time marked x.
- b. Which substrate provided “better’ growth conditions for the bacteria? How can you tell?
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Below is shown a growth curve for an E. coli culture. As indicated, the culture was incubated in the absence of a carbon source for 2 hours until Glucose and Lactose were added; Glucose was used up after 5 hours, and Lactose was used up after 8 hours. During the time-course, you take four samples, labeled A-D, after 1, 3, 7 and 9 hours, respectively, as indicated under the graph. Assuming there is cAMP present at t=0, for each sample identify whether CAP and/or the Lac Repressor would be bound to the DNA, and explain why.
Below is shown a growth curve for an E. coli culture. As indicated, the culture was incubated in the absence of a carbon source for 2 hours until Glucose and Lactose were added; Glucose was used up after 5 hours, and Lactose was used up after 8 hours. During the time-course, you take four samples, labeled A-D, after 1, 3, 7 and 9 hours, respectively, as indicated under the graph. Assuming there is cAMP present at t=0, for each sample identify whether CAP and/or the Lac Repressor would be bound to the DNA, and explain why.
A microbiology student was given a mixed culture of two different gram positive bacteria species to grow into a culture medium using correct aseptic techniques. After two days,one gram positive bacterial species grew on the media and the growth appeared red on the surface of the medium. Tthe second gram positive bacterial species grew and the growth appeared yellow on the surface of the medium. What is the possible explanation for the differences in the color of the bacterial growth?
A.
the culture was contaminated
B.
the microbiologist put too much inoculum on the culture medium
C.
the medium was a selective medium
D.
the medium was differential
Chapter 6 Solutions
MICROBIOLOGY-MASTERING MICRO.-ACCESS
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