bioprocess quiz questions

 1. What is the primary function of the motor in a batch fermentor?

A) To control temperature

B) To drive the impeller

C) To regulate pH

D) To monitor oxygen levels

Answer: B

2. The impeller in a batch fermentor helps to:

A) Prevent contamination

B) Introduce air

C) Maintain homogeneity

D) Measure flow rate

Answer: C

3. What is the function of the cooling jacket in a batch fermentor?

A) To introduce nutrients

B) To control pressure

C) To regulate temperature

D) To filter exhaust gases

Answer: C

4. In a batch fermentor, the inlet air filter ensures:

A) Pressure stability

B) Temperature control

C) Sterile air supply

D) pH balance

Answer: C

5. What is the purpose of baffles in a fermentor?

A) Measure oxygen levels

B) Prevent vortex formation

C) Monitor pH levels

D) Control foam formation

Answer: B

6. The primary function of a sparger in a batch fermentor is to:

A) Measure temperature

B) Control pH

C) Introduce air or oxygen

D) Regulate pressure

Answer: C

7. In a stirred tank bioreactor, the impeller:

A) Ensures even distribution of nutrients and oxygen

B) Introduces sterile air

C) Controls foam formation

D) Measures flow rate

Answer: A

8. What does the cooling jacket in a stirred tank bioreactor do?

A) Monitors pH

B) Controls temperature

C) Regulates oxygen supply

D) Measures pressure

Answer: B

9. The sparger in a stirred tank bioreactor introduces:

A) Nutrients

B) Oxygen

C) Cooling water

D) pH regulators

Answer: B

10. Which of the following is a feature of the batch fermentor process?

A) Continuous nutrient addition

B) Closed system

C) Open system

D) Steady-state operation

Answer: B

11. The exhaust air filter in a batch fermentor is used to:

A) Control oxygen levels

B) Prevent contamination

C) Measure pH

D) Regulate foam formation

Answer: B

12. Which bioreactor is most suitable for shear-sensitive cells?

A) Packed bed reactor

B) Stirred tank bioreactor

C) Airlift bioreactor

D) Fluidized bed reactor

Answer: C

13. What is one advantage of using a batch fermentor?

A) High productivity

B) Simple operation

C) Continuous production

D) Consistent product quality

Answer: B

14. Fed-batch processes allow for:

A) Continuous nutrient addition

B) Recycling of waste gases

C) Constant liquid volume

D) Immediate nutrient removal

Answer: A

15. Which part of a stirred tank bioreactor regulates the pH?

A) pH probe

B) Impeller

C) Cooling jacket

D) Motor

Answer: A

16. Airlift bioreactors are particularly suitable for:

A) High-energy processes

B) Shear-sensitive cultures

C) Solid catalysis

D) Continuous nutrient removal

Answer: B

17. What type of reactor is commonly used for processes involving solid catalysts?

A) Airlift reactor

B) Fluidized bed reactor

C) Stirred tank reactor

D) Packed bed reactor

Answer: D

18. What is one main advantage of the airlift bioreactor?

A) High shear stress

B) Low energy requirements

C) Large mixing requirement

D) Variable gas distribution

Answer: B

19. In bioreactor processes, foam formation is undesirable because it can:

A) Prevent sterilization

B) Interfere with gas exchange

C) Improve nutrient distribution

D) Increase pH levels

Answer: B

20. In fed-batch processes, the volume of the liquid:

A) Remains constant

B) Decreases

C) Increases

D) Is cycled out continuously

Answer: C

21. Which bioreactor type provides gentle mixing, making it suitable for culturing sensitive cells?

A) Stirred Tank Bioreactor

B) Airlift Bioreactor

C) Packed Bed Reactor

D) Fluidized Bed Reactor

Answer: B

22. The primary purpose of a rota meter in a fermentor is to:

A) Control the oxygen concentration

B) Measure the flow rate of air

C) Regulate temperature

D) Filter air before entering the fermentor

Answer: B

23. Which component of a bioreactor monitors and maintains pH levels?

A) Temperature probe

B) Impeller

C) pH probe

D) Baffles

Answer: C

24. In a continuous process, the culture medium:

A) Is replaced after each batch

B) Is maintained at a steady state

C) Has a constant oxygen supply

D) Is gradually diluted

Answer: B

25. Which of the following describes an advantage of using a stirred tank bioreactor (STB)?

A) Low energy consumption

B) Suitable for shear-sensitive cells

C) High scalability

D) No need for cooling

Answer: C

26. The main role of baffles in a fermentor is to:

A) Reduce shear stress

B) Prevent vortex formation

C) Increase foam formation

D) Control oxygen supply

Answer: B

27. A fed-batch process is characterized by:

A) Continuous removal of culture

B) Steady addition of nutrients

C) No addition of nutrients during the process

D) Regular pH monitoring only

Answer: B

28. What is the primary function of a diffuser in a packed bed reactor?

A) To increase oxygen concentration

B) To maintain sterility

C) To distribute reactants evenly

D) To remove excess heat

Answer: C

29. In a fluidized bed bioreactor, gas is introduced:

A) At the top of the reactor

B) Through a rotating impeller

C) Via a gas inlet at the bottom

D) Through the cooling jacket

Answer: C

30. A packed bed reactor is particularly useful for:

A) Suspended cultures

B) Shear-sensitive processes

C) Immobilized enzyme reactions

D) High energy processes

Answer: C

31. Which bioreactor operates without adding or removing material until the end of the process?

A) Continuous reactor

B) Batch reactor

C) Fed-batch reactor

D) Fluidized bed reactor

Answer: B

32. A stirred tank bioreactor's main feature is its:

A) High shear stress environment

B) Low nutrient usage

C) Efficient mixing

D) Lack of oxygen transfer

Answer: C

33. In an airlift bioreactor, the recirculation loop helps:

A) Remove excess gases

B) Improve nutrient distribution

C) Lower shear stress

D) Increase foam formation

Answer: B

34. The antifoam addition in a bioreactor serves to:

A) Increase oxygen supply

B) Control foam formation

C) Stabilize pH levels

D) Regulate nutrient addition

Answer: B

35. Continuous bioreactors operate by:

A) Allowing high shear forces

B) Starting and stopping regularly

C) Adding and removing material steadily

D) Producing no foam

Answer: C

36. What is one drawback of using stirred tank bioreactors?

A) High energy consumption

B) Poor temperature control

C) Low oxygen transfer

D) Limited scalability

Answer: A

37. In a fluidized bed reactor, the solid particles:

A) Are stationary throughout the process

B) Are suspended by the gas flow

C) Remain in the cooling jacket

D) Absorb excess foam

Answer: B

38. Which type of control system in bioreactors operates based on predictions of disturbances?

A) Feedback control

B) Combined control

C) Open-loop (Feedforward) control

D) Closed-loop control

Answer: C

39. A chemostat reactor operates by keeping:

A) A variable biomass concentration

B) Constant flow rates of media

C) Oxygen levels uncontrolled

D) pH at a set value without adjustments

Answer: B

40. What is the function of a pH transmitter in a bioreactor?

A) Measures dissolved oxygen

B) Controls nutrient flow

C) Converts pH signals for the controller

D) Directly adjusts pH

Answer: C

41. The cooling water outlet in a fermentor is responsible for:

A) Introducing cold water

B) Removing heated water

C) Controlling pH levels

D) Adjusting oxygen flow

Answer: B

42. In a continuous process with recycling, the recycled culture:

A) Increases cell density

B) Decreases nutrient utilization

C) Lowers gas exchange

D) Increases foam production

Answer: A

43. In a fluidized bed reactor, the gas bubbles are essential for:

A) Maintaining temperature

B) Fluidizing the solid particles

C) Removing byproducts

D) Stabilizing foam formation

Answer: B

44. What is a key advantage of a fed-batch bioreactor?

A) High shear stress

B) Easy nutrient removal

C) Enhanced product yield

D) Continuous culture recycling

Answer: C

45. The exhaust air filter in a fermentor:

A) Increases oxygen levels

B) Prevents contamination

C) Controls foam formation

D) Measures pH levels

Answer: B

46. Airlift bioreactors use a recirculation loop to:

A) Introduce new nutrients

B) Enhance liquid circulation

C) Increase shear forces

D) Remove foam

Answer: B

47. In a batch process, no additional materials are:

A) Added during the process

B) Controlled for pH

C) Removed until the end

D) Heated beyond set points

Answer: A

48. Which of the following is a disadvantage of batch fermentors?

A) Continuous operation

B) Risk of contamination

C) Variable product quality

D) Easy nutrient addition

Answer: C

49. Which bioreactor design is optimal for continuous nutrient supply without removing the culture medium?

A) Batch reactor

B) Fed-batch reactor

C) Packed bed reactor

D) Fluidized bed reactor

Answer: B

50. The purpose of the temperature probe in a stirred tank bioreactor is to:

A) Adjust oxygen levels

B) Monitor internal temperature

C) Regulate pH

D) Control pressure

Answer: B

51. In a fed-batch system, the nutrient concentration:

A) Remains constant throughout

B) Gradually increases

C) Decreases with cell growth

D) Is fully consumed immediately

Answer: B

52. Which reactor design minimizes shear stress on cells?

A) Stirred tank reactor

B) Fluidized bed reactor

C) Packed bed reactor

D) Airlift reactor

Answer: D

53. The acid/base addition system in a bioreactor is linked to the:

A) pH probe

B) Pressure gauge

C) Temperature probe

D) Rota meter

Answer: A

54. Which of the following processes allows for steady-state conditions?

A) Batch process

B) Fed-batch process

C) Continuous process

D) Cyclic process

Answer: C

55. What is the main disadvantage of fluidized bed reactors?

A) High maintenance costs

B) Complex flow dynamics

C) Limited oxygen transfer

D) Inconsistent temperature control

Answer: B

56. The primary function of a pressure gauge in a bioreactor is to:

A) Monitor temperature

B) Control nutrient levels

C) Ensure vessel integrity

D) Maintain pH balance

Answer: C

57. In which reactor type are reactants introduced at the bottom and flow upwards?

A) Stirred tank reactor

B) Airlift bioreactor

C) Packed bed reactor

D) Fluidized bed reactor

Answer: C

58. Continuous bioreactors are ideal for:

A) Small-scale batch processes

B) High-yield steady-state production

C) Processes requiring high shear forces

D) Short, time-limited experiments

Answer: B

59. Which control scheme adjusts the process based on feedback from the system’s output?

A) Open-loop control

B) Feedforward control

C) Feedback control

D) Predictive control

Answer: C

60. A pH control system in a bioreactor requires:

A) Temperature probes only

B) pH sensors and transmitters

C) Nutrient addition monitors

D) Foam control agents

Answer: B

61. A packed bed reactor's structure provides:

A) High shear force

B) High oxygen transfer

C) A large surface area for reactions

D) Rapid nutrient removal

Answer: C

62. What happens when the pH in a bioreactor deviates from the optimal range?

A) Oxygen levels stabilize

B) Enzyme activity decreases

C) Nutrient concentration increases

D) Temperature drops sharply

Answer: B

63. In bioreactor instrumentation, a thermocouple:

A) Monitors oxygen levels

B) Measures temperature

C) Adjusts foam levels

D) Controls pH

Answer: B

64. The acid valve in a pH control system is opened when:

A) The pH is below the setpoint

B) The pH is above the setpoint

C) Temperature increases

D) Nutrient levels drop

Answer: B

65. A major advantage of continuous reactors is:

A) High nutrient turnover

B) Simple operation

C) Constant product quality

D) Minimal energy consumption

Answer: C

66. What is a primary disadvantage of open-loop (feedforward) control in bioreactors?

A) Slow response time

B) Lack of feedback correction

C) High energy requirements

D) Frequent pH imbalance

Answer: B

67. An airlift bioreactor is ideal for cultures that:

A) Require high shear

B) Are shear-sensitive

C) Need rapid nutrient turnover

D) Produce excess foam

Answer: B

68. Foam in a bioreactor can:

A) Improve oxygen transfer

B) Block gas exchange

C) Stabilize pH

D) Enhance nutrient mixing

Answer: B

69. In a stirred tank bioreactor, the impeller:

A) Introduces gas directly

B) Aids in nutrient homogeneity

C) Controls pH automatically

D) Removes spent culture

Answer: B

70. What is the role of a sparger in a bioreactor?

A) Measure temperature

B) Provide foam control

C) Introduce oxygen

D) Control pH

Answer: C

71. In a batch process, the bioreactor is:

A) Continuously supplied with fresh nutrients

B) Operated as a closed system

C) Open to continuous waste removal

D) Constantly mixed with new inoculum

Answer: B

72. Which of the following bioreactor types is designed for continuous high-density cell cultivation?

A) Batch reactor

B) Fed-batch reactor

C) Continuous reactor

D) Packed bed reactor

Answer: C

73. Which control scheme anticipates changes and applies adjustments before the actual output is affected?

A) Feedback control

B) Feedforward control

C) Combined control

D) Closed-loop control

Answer: B

74. In a fluidized bed reactor, solid particles:

A) Settle at the bottom

B) Move in a circular flow

C) Are suspended by gas bubbles

D) Dissolve in the medium

Answer: C

75. Which component in a bioreactor monitors dissolved oxygen levels?

A) Rota meter

B) pH probe

C) Oxygen concentration probe

D) Temperature probe

Answer: C

76. The primary disadvantage of the fed-batch process is:

A) Lack of flexibility

B) Higher risk of contamination

C) Difficult temperature control

D) High shear stress

Answer: B

77. Airlift bioreactors typically operate with:

A) High energy requirements

B) High shear forces

C) Low energy consumption

D) Constant nutrient addition

Answer: C

78. What is a key feature of a batch fermentor?

A) Steady-state operation

B) High shear environment

C) Closed system with no additions or removals during the process

D) Continuous input and output of nutrients

Answer: C

79. In bioreactor temperature control, the heating jacket surrounds:

A) The cooling water inlet

B) The sparger

C) The vessel’s outer wall

D) The air filter

Answer: C

80. The purpose of the cooling jacket in a bioreactor is to:

A) Control pH levels

B) Maintain constant pressure

C) Regulate temperature

D) Prevent foam formation

Answer: C

81. Which type of reactor is best suited for immobilized enzyme reactions?

A) Stirred tank reactor

B) Airlift reactor

C) Packed bed reactor

D) Fluidized bed reactor

Answer: C

82. In a continuous process, the medium is:

A) Gradually consumed without replacement

B) Completely removed after each run

C) Continuously supplied and removed

D) Only partially filled at start

Answer: C

83. The pH sensor in a bioreactor provides data to:

A) Control nutrient addition

B) Adjust acid/base addition

C) Modify impeller speed

D) Reduce shear stress

Answer: B

84. Baffles in a stirred tank bioreactor help to:

A) Decrease foam formation

B) Prevent vortex formation

C) Regulate temperature

D) Monitor pressure

Answer: B

85. In which reactor type does the recirculation loop help to maintain a uniform environment?

A) Stirred tank reactor

B) Airlift reactor

C) Batch reactor

D) Packed bed reactor

Answer: B

86. A major challenge in operating a fluidized bed reactor is:

A) Low nutrient uptake

B) High cell density maintenance

C) Complex flow dynamics

D) Limited oxygen diffusion

Answer: C

87. Which of the following is NOT an advantage of batch fermentors?

A) Simple operation

B) High consistency in product quality

C) Low risk of contamination

D) Ideal for small-scale production

Answer: B

88. Feedforward control is ideal when:

A) Disturbances are unpredictable

B) Output correction is necessary

C) System behavior can be accurately modeled

D) Feedback loops are desired

Answer: C

89. A chemostat is a type of:

A) Batch reactor

B) Fed-batch reactor

C) Continuous reactor

D) Packed bed reactor

Answer: C

90. Which control system uses both predictive action and real-time error correction?

A) Feedback control

B) Feedforward control

C) Combined control

D) Open-loop control

Answer: C

91. What is a key feature of a continuous reactor with recycling?

A) No nutrient addition

B) High shear stress

C) Recycled biomass to increase cell density

D) Limited nutrient availability

Answer: C

92. Foam in bioreactors is typically controlled by:

A) Increasing the sparger rate

B) Using antifoam agents or foam breakers

C) Reducing pH

D) Adjusting the cooling jacket temperature

Answer: B

93. Which of the following bioreactors uses gas bubbles to create a fluidized state?

A) Packed bed reactor

B) Fluidized bed reactor

C) Stirred tank reactor

D) Continuous reactor

Answer: B

94. Continuous reactors are preferred in industries requiring:

A) High shear conditions

B) Small batch processing

C) Consistent and large-scale production

D) Frequent restarts and cleaning

Answer: C

95. In bioreactors, the oxygen concentration probe:

A) Controls pH levels

B) Measures dissolved oxygen levels

C) Increases mixing efficiency

D) Adds nutrients as needed

Answer: B

96. The acid/base addition system in a pH-controlled bioreactor operates based on:

A) Temperature readings

B) Pressure fluctuations

C) pH sensor data

D) Nutrient concentrations

Answer: C

97. A major advantage of using a continuous process is:

A) Lower contamination risk

B) High energy efficiency

C) Consistent product quality

D) Ease of operation

Answer: C

98. Fluidized bed reactors are often used in applications that require:

A) Low surface area contact

B) High heat generation

C) Efficient mass and heat transfer

D) Minimal particle movement

Answer: C

99. A major challenge with batch processes is:

A) High scalability

B) Constant pH maintenance

C) Consistent product quality

D) Reduced contamination risk

Answer: C

100. What role does the actuator play in a feedback control system?

A) Monitors temperature

B) Adjusts the process based on controller output

C) Measures pH

D) Controls foam levels

Answer: B