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Home Biochemical Engineering Fermentation Kinetics Comments

  • Question
  • The optical density sometimes drops during the lag phase because


  • Options
  • A. cells tend to grow without dividing leading to a decrease in the surface area to volume ratio
  • B. of fast cell growth causing them to fill up with DNA
  • C. cells swell up with water
  • D. cells swell up with RNA

  • Correct Answer
  • cells tend to grow without dividing leading to a decrease in the surface area to volume ratio 


  • Fermentation Kinetics problems


    Search Results


    • 1. Which of the following(s) is/are considered the limitations of the exponential growth model?

    • Options
    • A. Only predicts that cells grow exponentially during the log phase
    • B. It does not consider factors that causes cells growth to stop or slow
    • C. Predicts cell growth at a linear rate
    • D. All of the above
    • Discuss
    • 2. At the end of the lag phase, when growth begins, the division rate increases gradually and reaches a maximum value in the exponential growth period. This transitional period is commonly called the accelerated growth phase and is often included as a part of the

    • Options
    • A. lag phase
    • B. stationary phase
    • C. death phase
    • D. exponential growth phase
    • Discuss
    • 3. Concentration of the growth limiting substrate means

    • Options
    • A. trace elements concentration
    • B. the concentration of the substrate that controls the growth rate of the cells
    • C. sugar concentration in the fermentation medium
    • D. dissolved oxygen concentration
    • Discuss
    • 4. Residence time distribution (RTD) of a reactor is independent of

    • Options
    • A. micro mixing
    • B. volume of reactor
    • C. height of the reactor
    • D. width of the reactor
    • Discuss
    • 5. In an airlift bioreactor, the air sparging region is called

    • Options
    • A. downcomer
    • B. disengagement zone
    • C. air riser
    • D. none of these
    • Discuss
    • 6. Stirred tank fermenter (STF) can be employed for

    • Options
    • A. aerobic fermentation of a wide range of cells including microbial, animal and plant cells
    • B. anaerobic fermentation of a wide range of cells including microbial, animal and plant cells
    • C. Both (a) and (b)
    • D. anaerobic fermentation of plant cells only
    • Discuss
    • 7. Which of the following statements would be appropriate while comparing bubble column and air lift fermenter of the same size?

    • Options
    • A. The average bubble size is smaller in an airlift bioreactor
    • B. Oxygen transfer rate is higher in an airlift bioreactor
    • C. The surface area for gas exchange is higher in an airlift bioreactor
    • D. All of the above
    • Discuss
    • 8. The air riser is located on the outside of the draft tube for the large-scale airlift bioreactors because of

    • Options
    • A. higher oxygen transfer rates
    • B. a small sparge ring
    • C. better heat transfer efficiencies
    • D. all of these
    • Discuss
    • 9. The application of just in time (JIT) manufacturing techniques in biotechnology is important because

    • Options
    • A. raw materials used in biotechnology are biodegradable
    • B. the products of biotechnology are biodegradable
    • C. it is a very competitive business (d) all of the above
    • D. all of the above
    • Discuss
    • 10. The height to diameter ratio (H/D) for the tank fermenters is

    • Options
    • A. <3
    • B. >3
    • C. <1.5
    • D. >1.5
    • Discuss


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