Chapter 6 Microbial Growth

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Chapter 6 Microbial Growth
Batch and Continuous Cultures
Temperature and Salt Effects
Growth Calculations
pH and O2 Effects
Growth Potpourri
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FINAL ROUND
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Topic 1 Growth Calculations 100 Question

• Question Lucy diluted a sample to a factor of
  10-4 (or 1/104) and did a spread plate of 1 ml of
  the diluted culture. The next day she counted 87
  colonies on the plate. What was the concentration
  of the original sample?
• a. 8.7 X 103 cfu/ml sample
• b. 8.7 X 104 cfu/ml sample
• c. 8.7 X 105 cfu/ml sample
• d. 8.7 X 106 cfu/ml sample

ANSWER
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Topic 1 Growth Calculations 100 Answer

• Question Lucy diluted a sample to a factor of
  10-4 (or 1/104) and did a spread plate of 1 ml of
  the diluted culture. The next day she counted 87
  colonies on the plate. What was the concentration
  of the original sample?
• a. 8.7 X 103 cfu/ml sample
• b. 8.7 X 104 cfu/ml sample
• c. 8.7 X 105 cfu/ml sample
• d. 8.7 X 106 cfu/ml sample

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4
Topic 1 Growth Calculations200 Question

• Question Assume you have an exponentially
  growing cell population. If the log number of
  starting cells is 2 and the log number of cells
  after 12 hours is 6, what is the number of
  generations?
• a. 13.2 generations
• b. 4.2 generations
• c. 8.1 generations
• d. 6.0 generations

ANSWER
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Topic 1 Growth Calculations 200 Answer

• Question Assume you have an exponentially
  growing cell population. If the log number of
  starting cells is 2 and the log number of cells
  after 12 hours is 6, what is the number of
  generations?
• a. 13.2 generations
• b. 4.2 generations
• c. 8.1 generations
• d. 6.0 generations

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Topic 1 Growth Calculations 300 Question

• Question Assume you have an exponentially
  growing cell population. If the log number of
  starting cells is 2 and the log number of cells
  after 12 hours is 6, what is the generation time?
• a. 13.2 minutes
• b. 120.8 minutes
• c. 54.6 minutes
• d. 4.5 minutes

ANSWER
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Topic 1 Growth Calculations 300 Answer

• Question Assume you have an exponentially
  growing cell population. If the log number of
  starting cells is 2 and the log number of cells
  after 12 hours is 6, what is the generation time?
• a. 13.2 minutes
• b. 120.8 minutes
• c. 54.6 minutes
• d. 4.5 minutes

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Topic 1 Growth Calculations 400 Question

• Question If you have 100 cells at 100 p.m. and
  these cells have a generation time of 30 minutes,
  how many cells do you have at 500 p.m. (assuming
  the cells are growing exponentially)?
• a. 400 cells
• b. 800 cells
• c. 1,600 cells
• d. 25,600 cells

ANSWER
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Topic 1 Growth Calculations 400 Answer

• Question If you have 100 cells at 100 p.m. and
  these cells have a generation time of 30 minutes,
  how many cells do you have at 500 p.m. (assuming
  the cells are growing exponentially)?
• a. 400 cells
• b. 800 cells
• c. 1,600 cells
• d. 25,600 cells

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Topic 1 Growth Calculations 500 Question

• Question If cell A has a k value of 0.04 and
  Cell B has a k value of 0.02, which of the
  following is/are true?
• a. A grows slower than B
• b. A has a shorter generation time than B
• c. if you were to plot exponential growth for
  both A and B, B would have a larger slope.
• d. all of the above

ANSWER
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Topic 1 Growth Calculations 500 Answer

• Question If cell A has a k value of 0.04 and
  Cell B has a k value of 0.02, which of the
  following is/are true?
• a. A grows slower than B
• b. A has a shorter generation time than B
• c. if you were to plot exponential growth for
  both A and B, B would have a larger slope.
• d. all of the above

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Topic 2 Batch and Continuous Cultures100
Question

• True or False. A culture in a test tube is an
  example of a batch culture.
• a. true
• b. false

ANSWER
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Topic 2 Batch and Continuous Cultures 100
Answer

• True or False. A culture in a test tube is an
  example of a batch culture.
• a. true
• b. false

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Topic 2 Batch and Continuous Cultures 200
Question

• Question When do batch cultures enter
  stationary phase?
• a. when the temperature of the culture changes
• b. when the culture is transferred to fresh
  media
• c. when the nutrient concentration in the
  media is diminished
• d. all of the above

ANSWER
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Topic 2 Batch and Continuous Cultures 200
Answer

• Question When do batch cultures enter
  stationary phase?
• a. when the temperature of the culture changes
• b. when the culture is transferred to fresh
  media
• c. when the nutrient concentration in the
  media is diminished
• d. all of the above

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Topic 2 Batch and Continuous Cultures 300
Question

• Question Which of the following is true about
  death phase?
• a. absolutely no new cells form during this
  phase
• b. the number of dying cells is greater than
  the number of new cells
• c. all new cells that form during this phase
  immediately die
• d. the number of new cells is equal to the
  number of dying cells

ANSWER
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Topic 2 Batch and Continuous Cultures 300
Answer
Question Which of the following is true about
death phase? a. absolutely no new cells form
during this phase b. the number of dying cells
is greater than the number of new cells c. all
new cells that form during this phase
immediately die d. the number of new cells is
equal to the number of dying cells
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Topic 2 Batch and Continuous Cultures 400
Question

• Question During lag phase cells are not very
  metabolically active.
• a. true
• b. false

ANSWER
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Topic 2 Batch and Continuous Cultures 400
Answer

• Question During lag phase cells are not very
  metabolically active.
• a. true
• b. false

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Topic 2 Batch and Continuous Cultures 500
Question

• Question Consider a chemostat. If you were to
  increase the dilution rate slightly, what would
  happen? (Assume the chemostat is in steady
  state.)
• a. bacterial concentration or growth yield would
  increase in the chemostat
• b. doubling time of the culture in the chemostat
  would decrease
• c. growth yield would increase while doubling
  time would decrease in the chemostat
• d. growth yield and doubling time would
  increase in the chemostat

ANSWER
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Topic 2 Batch and Continuous Cultures 500
Answer
Question Consider a chemostat. If you were to
increase the dilution rate slightly, what would
happen? (Assume the chemostat is in steady
state.) a. bacterial concentration or growth
yield would increase in the chemostat b.
doubling time of the culture in the chemostat
would decrease c. growth yield would increase
while doubling time would decrease in the
chemostat d. growth yield and doubling time
would increase in the chemostat
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Topic 3 Temperature and Salt Effects 100
Question

• Question When a culture is incubated at a
  temperature that is above the organisms maximum
  temperature for growth, what happens?
• a. the transport of nutrients into the cell is
  slow therefore the cells grow more slowly
  than normal
• b. the cells grow much faster than normal
  because the enzymatic reactions are occurring
  at a much faster rate.
• c. the cell membranes collapse and proteins
  denature and the cell usually dies
• d. the cell continues to grow at the normal
  rate

ANSWER
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Topic 3Temperature and Salt Effects 100 Answer

• Question When a culture is incubated at a
  temperature that is above the organisms maximum
  temperature for growth, what happens?
• a. the transport of nutrients into the cell is
  slow therefore the cells grow more slowly
  than normal
• b. the cells grow much faster than normal
  because the enzymatic reactions are occurring
  at a much faster rate.
• c. the cell membranes collapse and proteins
  denature and the cell usually dies
• d. the cell continues to grow at the normal
  rate

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Topic 3 Temperature and Salt Effects 200
Question

• Question Which type of organism would you most
  likely find growing well in your refrigerator?
• a. mesophile
• b. psychrophile
• c. psychrotolerant
• d. thermophile

ANSWER
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Topic 3 Temperature and Salt Effects 200 Answer

• Question Which type of organism would you most
  likely find growing well in your refrigerator?
• a. mesophile
• b. psychrophile
• c. psychrotolerant
• d. thermophile

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Topic 3 Temperature and Salt Effects 300
Question

• Question What is the optimum temperature for a
  thermophile?
• a. above 80 degrees C
• b. 45 to 80 degrees C
• c. 20 to 50 degrees C
• d. below 40 degrees C

ANSWER
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Topic 3 Temperature and Salt Effects 300 Answer

• Question What is the optimum temperature for a
  thermophile?
• a. above 80 degrees C
• b. 45 to 80 degrees C
• c. 20 to 50 degrees C
• d. below 40 degrees C

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Topic 3 Temperature and Salt Effects 400
Question

• Question If an organism thrives in an
  environment where the aw (water activity) is
  0.75, this organism is _______________.
• a. a thermophile
• b. halotolerant
• c. an extreme halophile
• d. a xerophile

ANSWER
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Topic 3 Temperature and Salt Effects 400 Answer

• Question If an organism thrives in an
  environment where the aw (water activity) is
  0.75, this organism is _______________.
• a. a thermophile
• b. halotolerant
• c. an extreme halophile
• d. a xerophile

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Topic 3 Temperature and Salt Effects 500
Question

• Question If you placed a mesophile at 20
  degrees C, what would happen?
• a. it would die
• b. it would grow optimally
• c. it would grow less than optimally
• d. it would lyse open

ANSWER
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Topic 3 Temperature and Salt Effects 500 Answer

• Question If you placed a mesophile at 20
  degrees C, what would happen?
• a. it would die
• b. it would grow optimally
• c. it would grow less than optimally
• d. it would lyse open

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Topic 4 pH and O2 Effects 100 Question

• Question Which organism grows well at reduced
  oxygen levels?
• a. Obligate anaerobe
• b. Aerotolerant
• c. Microaerophile
• d. Obligate aerobe

ANSWER
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Topic 4 pH and O2 Effects 100 Answer

• Question Which organism grows well at reduced
  oxygen levels?
• a. Obligate anaerobe
• b. Aerotolerant
• c. Microaerophile
• d. Obligate aerobe

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Topic 4 pH and O2 Effects 200 Question

• Question In the picture below, organism c is
  _______________.
• a. a facultative aerobe
• b. an obligate aerobe
• c. a microaerophile
• d. aerotolerant

ANSWER
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Topic 4 pH and O2 Effects 200 Answer

• Question In the picture below, organism c is
  _______________.
• a. a facultative aerobe
• b. an obligate aerobe
• c. a microaerophile
• d. aerotolerant

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Topic 4 pH and O2 Effects300 Question

• True or False. Obligate anaerobes require the
  enzyme catalase to detoxify by products of
  metabolism.
• a. true
• b. false

ANSWER
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Topic 4 pH and O2 Effects 300 Answer

• True or False. Obligate anaerobes require the
  enzyme catalase to detoxify by products of
  metabolism.
• a. true
• b. false

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Topic 4 pH and O2 Effects 400 Question

• Question Which of the following organisms have
  a particularly difficult time maintaining a
  proton motive force?
• a. psychrophiles
• b. acidophiles
• c. osmophiles
• d. alkaliphiles

ANSWER
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Topic 4 pH and O2 Effects 400 Answer

• Question Which of the following organisms have
  a particularly difficult time maintaining a
  proton motive force?
• a. psychrophiles
• b. acidophiles
• c. osmophiles
• d. alkaliphiles

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Topic 4 pH and O2 Effects 500 Question

• Question An organism that grows at a pH of 9 is
  a(n) _______________.
• a. acidophile
• b. thermophile
• c. alkaliphile
• d. osmophile

ANSWER
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Topic 4 pH and O2 Effects 500 Answer

• Question An organism that grows at a pH of 9 is
  a(n) _______________.
• a. acidophile
• b. thermophile
• c. alkaliphile
• d. osmophile

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Topic 5 Growth Potpourri 100 Question

• Question Before an indirect method, such as
  turbidity readings, can be used to measure cell
  concentration a _______________ has to be
  prepared.
• a. standard curve
• b. growth curve
• c. standard culture
• d. fermentation balance

ANSWER
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Topic 5 Growth Potpourri 100 Answer

• Question Before an indirect method, such as
  turbidity readings, can be used to measure cell
  concentration a _______________ has to be
  prepared.
• a. standard curve
• b. growth curve
• c. standard culture
• d. fermentation balance

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Topic 5 Growth Potpourri 200 Question

• Question Disrupting the MreB protein in a
  rod-shaped cell could have what effect on the
  cell?
• a. cells could appear coccus shaped
• b. cells wont divide
• c. cells will appear filamentous and
  temperature sensitive
• d. cell would appear curved

ANSWER
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Topic 5 Growth Potpourri 200 Answer

• Question Disrupting the MreB protein in a
  rod-shaped cell could have what effect on the
  cell?
• a. cells could appear coccus shaped
• b. cells wont divide
• c. cells will appear filamentous and
  temperature sensitive
• d. cell would appear curved

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Topic 5 Growth Potpourri 300 Question

• Question A _______________ is used to estimate
  culture concentration by measuring turbidity.
• a. pour plate method
• b. viable count
• c. spectrophotometer
• d. microscope

ANSWER
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Topic 5 Growth Potpourri 300 Answer

• Question A _______________ is used to estimate
  culture concentration by measuring turbidity.
• a. pour plate method
• b. viable count
• c. spectrophotometer
• d. microscope

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Topic 5 Growth Potpourri 400 Question

• Question What is the name of the group of
  proteins that direct the placement of FtsZ in E.
  coli?
• a. Fts proteins (FtsA, FtsI, FtsK)
• b. MreB proteins
• c. Min proteins (MinC, MinE)
• d. bactoprenol

ANSWER
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Topic 5 Growth Potpourri 400 Answer

• Question What is the name of the group of
  proteins that direct the placement of FtsZ in E.
  coli?
• a. Fts proteins (FtsA, FtsI, FtsK)
• b. MreB proteins
• c. Min proteins (MinC, MinE)
• d. bactoprenol

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Topic 5 Growth Potpourri 500 Question

• Question If a cell were unable to produce
  bactoprenol, what would happen?
• a. the cell would autolyse
• b. its offspring would be smaller than usual
• c. the cells doubling time would decrease
• d. the cell would change its shape

ANSWER
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Topic 5 Growth Potpourri 500 Answer

• Question If a cell were unable to produce
  bactoprenol, what would happen?
• a. the cell would autolyse
• b. its offspring would be smaller than usual
• c. the cells doubling time would decrease
• d. the cell would change its shape

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FINAL ROUND Question

• Question If you wanted to increase the growth
  yieldof a continuous culture you would
  _______________.
• a. increase the concentration of the nutrients
  in the culture
• c. increase the dilution rate of the continuous
  culture (flow rate of media)
• b. decrease the concentration of the nutrients
  in the culture
• d. decrease the dilution rate of the continuous
  culture (flow rate of media)

ANSWER
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FINAL ROUND Answer

• Question If you wanted to increase the growth
  yield of a continuous culture you would
  _______________.
• a. increase the concentration of the nutrients
  in the culture
• c. increase the dilution rate of the continuous
  culture (flow rate of media)
• b. decrease the concentration of the nutrients
  in the culture
• d. decrease the dilution rate of the continuous
  culture (flow rate of media)

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