Foundational Microbiology 3: Microbial Growth and Nutrition
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Questions and Answers

Which method is used to measure population size when dealing with a large population?

  • Turbidity
  • Streaking
  • Membrane filtration
  • Serial dilutions (correct)

    • What happens to the inoculum during streaking across the agar plate?

  • It is diluted (correct)
  • It is filtered
  • It is concentrated
  • It is incubated

    • What is the purpose of streaking the inoculum across successive areas of the plate?

  • To dilute the inoculum (correct)
  • To concentrate the inoculum
  • To filter the inoculum
  • To incubate the inoculum

    • Which method is used to measure population size when dealing with a small population?

    <p>Membrane filtration</p> Signup and view all the answers

    What does the membrane filter retain during population size measurement?

    <p>Bacterial cells</p> Signup and view all the answers

    What is done with the membrane filter after it retains the cells?

    <p>It is incubated</p> Signup and view all the answers

    What is the purpose of turbidity measurement in population size estimation?

    <p>To indirectly estimate the population size</p> Signup and view all the answers

    Which method is used for measuring population size when dealing with large populations indirectly?

    <p>Turbidity</p> Signup and view all the answers

    What is the purpose of incubation in population size measurement?

    <p>To allow colonies to form</p> Signup and view all the answers

    Which of the following is NOT a characteristic of biofilms?

    <p>They are caused by bacterial diseases</p> Signup and view all the answers

    What is the purpose of agar in solid media?

    <p>To solidify the media</p> Signup and view all the answers

    Which type of media contains substances that either favor the growth of particular microorganisms or inhibit the growth of unwanted ones?

    <p>Selective media</p> Signup and view all the answers

    What is the purpose of differential media?

    <p>To differentiate among different bacteria</p> Signup and view all the answers

    What is the main purpose of the streak plate method?

    <p>To isolate organisms into a pure culture</p> Signup and view all the answers

    What is the key requirement for a pure culture?

    <p>Aseptic technique</p> Signup and view all the answers

    What is the purpose of the Durham tube in carbohydrate utilization tubes?

    <p>To trap gas produced during fermentation</p> Signup and view all the answers

    During which phase of the microbial growth curve do cells grow at their maximum rate and there are no limitations to nutrients?

    <p>Exponential phase</p> Signup and view all the answers

    What happens during the stationary phase of the microbial growth curve?

    <p>Nutrients are depleted and wastes accumulate</p> Signup and view all the answers

    What is the equation used to calculate the log10 number of viable cells at a given time (Nt)?

    <p>$Nt = \log_{10} Nt 0$</p> Signup and view all the answers

    What is the lag phase of the microbial growth curve?

    <p>Most cells do not reproduce immediately</p> Signup and view all the answers

    When does the microbial growth curve reach the long-term stationary phase?

    <p>When cells die at a faster rate than they are produced</p> Signup and view all the answers

    What happens during the death phase of the microbial growth curve?

    <p>Cells die at a faster rate than they are produced</p> Signup and view all the answers

    What is the effect of dying cells releasing nutrients during the long-term stationary phase?

    <p>Remaining cells feed off these nutrients</p> Signup and view all the answers

    Which of the following is true about generation time?

    <p>It is the time required for a population of cells to double in number.</p> Signup and view all the answers

    What is the generation time for Escherichia coli at 37°C?

    <p>0.5 hours</p> Signup and view all the answers

    Which of the following organisms has the shortest generation time?

    <p>Escherichia coli</p> Signup and view all the answers

    Which of the following factors affects microbial growth?

    <p>All of the above</p> Signup and view all the answers

    Which of the following pH ranges is considered acidic?

    <p>0.0-5.5</p> Signup and view all the answers

    Which of the following temperature ranges is suitable for the growth of psychrophiles?

    <p>-10°C to 10°C</p> Signup and view all the answers

    Which of the following organisms is an obligate anaerobe?

    <p>Clostridium botulinum</p> Signup and view all the answers

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