# Fermentation Technology Questions and Answers – Fermentation Laboratory – Harvesting and Disrupting Cells

This set of Fermentation Technology Multiple Choice Questions & Answers (MCQs) focuses on “Fermentation Laboratory – Harvesting and Disrupting Cells “.

1. What is the flow rate of Autoclude V8/55/24HR?
a) 350 mL/min
b) 8 L/min
c) 8 mL/min
d) 350 L/min

Explanation: The flow rate of Autoclude V8/55/24HR is 8 L/min. It is a variable speed peristaltic pump used for the large scale centrifugation. The range of pumps can be extinguished between panel mounted and free-standing.

2. The flow rate of Watson Marlow 501 was _______________
a) 350 mL/min
b) 350 dL/min
c) 350 µL/min
d) 350 L/min

Explanation: The flow rate of Watson Marlow 501 peristaltic pump was approximately up to 350 mL/min. It was used for the lower volume of cell harvesting. They are accurate pumps with low maintenance and are simple to install and easy to use.

3. The flow rate of Haraeus continuous centrifuge is ______________
a) 10 mL/h
b) 8 L/h
c) 8 mL/h
d) 10 L/h

Explanation: The flow rate of Haraeus continuous flow centrifuge is 10 L/h. It has a smaller capacity but gives excellent clarity of supernatant. This machine cannot be used for cultures above 10 L volume because of low flow rates.

4. The capacity of rotor of Cepa Z41 centrifuge is _____________
a) 850 g of wet cells
b) 750 g of wet cells
c) 750 g of dry cells
d) 850 g of dry cells

Explanation: The capacity of the rotor of Cepa Z41 tubular bowl centrifuge is 750 g of wet cells. It is a high-speed peristaltic pump which gives high clarity and high throughput. About 30 L of cell is harvested within 20 minutes of time and 100 L in an hour.

5. Which of the following uses the membrane to concentrate cell suspension?
a) Cepa Z41
b) Watson Marlow 501
c) Filtration
d) Autoclude V8

Explanation: Filtration uses the membrane to concentrate the cell suspension. It is also known as tangential flow filtration. Cell washing can also be done through cross-flow filtration before centrifugation, although the process is time-consuming.
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6. Which of the following is not the function of buffer?
a) Prevent cell lysis
b) Chelating the metals
c) Prevent protease action
d) Prevent lipase action

Explanation: The buffer is used to prevent the lysis of cells, and chelate the metals and prevent the action of protease enzymes. The buffer is added to the pellet prior to processing and defrosting.

7. The number of bacteria can be determined by ___________
a) Streaking
b) Four flame method
c) Pour plate
d) Pour plate and spread plate

Explanation: The number of bacteria can be determined quantitatively by pour plate and spread plate technique due to a higher degree of dilution. The number of colonies can be counted which helps us to determine the number of bacteria present in a liquid specimen.

8. Which of the following is the method of cell disruption?
a) Sonication
b) Homogenization
c) Streaking
d) Chemical Treatment

Explanation: Streaking is not the method of cell disruption. It is used in isolation of species of microorganisms like bacteria. Sonication, homogenization, chemical treatment is used in the disruption of cells in order to get intracellular fluid.

9. Which of the following technique uses sound waves for cell disruption?
a) Homogenization
b) Sonication
c) Blender
d) Mortar and Pestle

Explanation: Sonication uses the sound waves of high frequency and vibrations for the disruption of cells. It is mostly used for fungal and plant cells but its disadvantage is it creates a lot of noise and needs a separate room for it.

10. Which of the following method uses a solvent (mostly water) for cell disruption?
a) Homogenization
b) Sonication
c) Blender
d) Osmotic shock

Explanation: Osmotic shock uses a solvent (mostly water) for the disruption of cells. The water can be moved inside the cells using osmosis causing the cell to increase in the volume and finally bursting of cells occur.

11. Chitinase is used for the disruption of __________ cell wall.
a) Bacterial
b) Plant
c) Fungal
d) Animal

Explanation: Chitinase is used for the disruption of the cell wall of fungi. The cell wall of fungi is made up of chitin and it gives the structural strength to the cell. It is also present in the exoskeleton of a few insects and protects the cell wall from desiccation. Thus, the use of chitinase can break the cell wall of fungi.

12. Which of the following is not the product of cell disruption?
a) DNA
b) RNA
c) Protein
d) Water

Explanation: Water is not the product of cell disruption as water is freely available outside whereas, DNA, RNA, Proteins, Toxins, Insulin, Growth Hormone, etc. are the products of cell disruption.

13. Which of the following is a physical method of cell disruption?
a) Using detergents
b) Using solvents
c) Using French press
d) Using osmotic shock

Explanation: The physical method of cell disruption is using a French press. Other physical methods include bead mill, colloid mill, ultrasonic vibrations, etc. Using detergents, solvents, enzymes, the osmotic shock is an example of chemical cell disruption.

14. The Haraeus centrifuge is not used for volume above 10 L.
a) True
b) False

Explanation: The Haraeus continuous flow centrifuge is used only for volume below 10 L as the capacity of the centrifuge is smaller and it also has a very low flow rate of 10 L/h. That is why it is not suitable to use it with more than 10 L of volume.

15. Lysozyme is used for bacterial cell disruption.
a) True
b) False

Explanation: Lysozyme is used for the disruption of the cell wall of bacteria. It targets the peptidoglycan layer which is mainly present in the Gram-negative bacterial cell wall. Lysozyme also has its applications in the preservation of food items like fruits, vegetables, cheese, sauce, etc.

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