This set of Bioseparation Technology Multiple Choice Questions & Answers (MCQs) focuses on “Cell Disruption using Rotor-Stator Mill and French Press”.
1. What is the working principle of rotor-stator mill?
a) Cell disruption
b) Sedimentation
c) Filtration
d) Centrifugation
View Answer
Explanation: The rotor-stator mills are the physical method of cell disruption and it breaks the cells depending on the type of cell.
2. What are the major components of rotor-stator mill?
a) Stator
b) Stator and rotor
c) Fixed Rotor
d) Moving rotor
View Answer
Explanation: The stator is a stationary block having tapered cavity and rotor is the truncated cone shaped rotating object.
3. What is the rotation speed of rotor-stator mill?
a) 1000-5000 rpm
b) 100-500 rpm
c) 10,000-50,000 rpm
d) 10-50 rpm
View Answer
Explanation: It requires high speed of rotation for the disruption of cells. Low speed will not allow the cells to be ruptured. High speed generates high rate of shear which generates turbulence and is responsible for the cell disruption.
4. The feed is drawn in the rotor stator due to _____________
a) Revolution
b) Centrifugation
c) Sedimentation
d) Rotation
View Answer
Explanation: Rotation leads to drawing of feed in the rotor stator and then the feed is expelled out through the outlet because of the centrifugal action in the mill. This leads to movement of the cells outward.
5. Rotor stator mill is used for disruption of _____________
a) Plant and animal tissues
b) Plant and animal cells
c) Plant tissue
d) Animal tissue
View Answer
Explanation: Plant and animal tissues can be disrupted by using rotor stator mill. The disruption is based on the material to be disrupted and it is operated in the multi-pass mode where, the disrupted material is moved back to the device for overall and complete disruption.
6. Which equation describes the cell disruption within the rotor-stator mill?
a) \(\frac{C}{C_{max}}\) = -exp(-\(\frac{t}{\theta}\))
b) \(\frac{C}{C_{max}}\) = (1 – exp(-\(\frac{t}{\theta}))^N\)
c) \(\frac{C}{C_{max}}\) = 1 + exp(-\(\frac{t}{\theta}\))
d) \(\frac{C}{C_{max}}\) = exp(-\(\frac{t}{\theta}\))
View Answer
Explanation: \(\frac{C}{C_{max}}\) = (1 – exp(-\(\frac{t}{\theta}))^N\) is used to express the cell disruption by using rotor-stator mills, where N is the number of passes, C is the concentration at initial stage, Cmax is the maximum concentration at the outlet, t is the time taken for the disruption of cell. It is used in multi-passes mode of operation.
7. Which products can be disrupted using French press?
a) proteins and DNA
b) Bacterial and plant cell
c) proteins and DNA from bacterial and plant cell
d) Yeast cell
View Answer
Explanation: French press is used for small scale recovery of intracellular proteins and DNA from bacterial cells and the plant cells. It is also used for disintegration of many cell organelles like chloroplast and is capable of disrupting cell walls without disturbing the nucleus.
8. The components of French press are _____________
a) Rotor
b) Beads
c) Cylinder
d) Plunger, cylinder
View Answer
Explanation: It consists of a cylinder with plunger fitted by hydraulic press and the cell suspension is placed in the cylinder and pressure is applied from the top using plunger. The cylinder has an orifice through which the suspension emerges at high velocity in a form of jet spray.
9. Cell disruption takes place due to low shear rates in French press.
a) False
b) True
View Answer
Explanation: Cell disruption takes place due to the high shear rates which influences the cells to ooze out of the orifice. It is frequently provided with an impact plate and the jet, the jet impinges leads to cell disruption.
10. What is the capacity of French press?
a) 1ml – 10ml
b) 1ml – 100ml
c) 1ml – 5ml
d) 1ml
View Answer
Explanation: The volume which can be handled by the French press is around 1ml – 100ml and it is not suited for the disruption of large volumes. It generates inside-out vesicles in the membrane and cells are stored under cryopreservation in order to avoid loss of enzymatic activity.
11. What is the operating range of pressure in French press?
a) 10 – 50 psig
b) 100 – 500 psig
c) 10,000 – 50,000 psig
d) 10,00 – 50,00 psig
View Answer
Explanation: The high pressure is required for the disruption of tissues because at low pressure the desired material will not rupture and the desired product will remain intracellular.
Sanfoundry Global Education & Learning Series – Bioseparation Technology.
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