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  • Question
  • In sparged mammalian cell bioreactors, the cell damage is caused because of


  • Options
  • A. shear stress arising during mixing of the cell culture fluid
  • B. shear stresses arising from the breakup of bubbles at the liquid surface
  • C. shear stresses between bubbles in foam at the liquid surface
  • D. all of the above

  • Correct Answer
  • shear stress arising during mixing of the cell culture fluid 


  • Fluid Flow problems


    Search Results


    • 1. A Brookfield viscometer measures viscosity by determining

    • Options
    • A. the shear stress
    • B. the shear rate
    • C. the shear stress and shear rate
    • D. the torque required to move an impeller at a set speed
    • Discuss
    • 2. A fluid in which the viscosity decreases with increasing stirrer speed and mixing time, can be represented as

    • Options
    • A. newtonian fluid
    • B. pseudoplastic, thixotropic fluid
    • C. dilatant, rheopectic fluid
    • D. dilatant, pseudoplastic fluid
    • Discuss
    • 3. Which of the following compound, if added to a solution will lead to the greatest increase in viscosity?

    • Options
    • A. A globular protein
    • B. Glucose
    • C. A long chain protein such as albumin
    • D. Water
    • Discuss
    • 4. In animal cell bioreactor, bubble damage can be minimized by

    • Options
    • A. the addition of a shear protectorant
    • B. using a bubble free oxygen delivery system
    • C. headspace aeration
    • D. all of the above
    • Discuss
    • 5. A dilatant fluid is one in which the viscosity

    • Options
    • A. is constant regardless of the stirrer speed or mixing time
    • B. changes during mixing but returns to its original state after mixing
    • C. increases with increasing stirrer speed
    • D. decreases with increasing stirrer speed
    • Discuss
    • 6. The SI unit for viscosity is

    • Options
    • A. kg.m-1.s-1
    • B. kg.m-2.s-2
    • C. kg.m-3.s-1
    • D. kg.m-1.s-2
    • Discuss
    • 7. A pseudoplastic fluid is one in which the viscosity

    • Options
    • A. is constant regardless of the stirrer speed or mixing time
    • B. changes during mixing but returns to its original state after mixing
    • C. increases with increasing stirrer speed
    • D. decreases with increasing stirrer speed
    • Discuss
    • 8. The medium will have the highest viscosity (considering that the cells do not secrete gums) with the presence of

    • Options
    • A. single celled bacteria
    • B. filamentous fungi that form pellets
    • C. filamentous fungi that grow as long poorly branched chains
    • D. yeast
    • Discuss
    • 9. The viscosity of a fluid changes with either stirrer speed or mixing time. But when mixing ceases, the viscosity returns to its original state. This fluid is best described as

    • Options
    • A. newtonian
    • B. rheopectic
    • C. viscoelastic
    • D. thixotropic
    • Discuss
    • 10. A liquid is flowing at 11,400 l.h-1 along a pipeline having a diameter of 4 cm. If the liquid has a density of 1 g.ml-1 and viscosity of 0.001kg.m-1.s-1, then the liquid would be in the

    • Options
    • A. laminar phase
    • B. transient phase
    • C. turbulent phase
    • D. any of the phase
    • Discuss


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