Biochem - Fluid Flow Flashcards
1
Q
- The viscosity of liquid was classified as both dilatant and rheopectic, which means that the viscosity
A
- Increased with stirring speed and increased with mixing time
2
Q
- Which of the following describes the detrimental effect of bubbles on animal cells?
A
- Both (a) and (b)
3
Q
- A fluid in which the viscosity decreases with increasing stirrer speed and mixing time, can be represented as
A
- Pseudoplastic, thixotropic fluid
4
Q
- Filamentous fungal cells are more shear sensitive than bacterial cells because of
A
- All of the above
5
Q
- The viscosity of water at STP is approximately
A
- 0.001 kg.m-1.s-1
6
Q
- Bubble free aeration systems requires
A
- Silicone tubing or gas permeable membranes to facilitate gas transfer
7
Q
- Non-linear relationship between shear stress and shear rate exists in
A
- Non-Newtonian fluids
8
Q
- If the viscosity of a fluid decreases with increasing stirrer speed, then the nature of the fluid is
A
- Pseudoplastic
9
Q
- A pseudoplastic fluid is one in which the viscosity
A
- Decreases with increasing stirrer speed
10
Q
- A viscoelastic fluid is one in which the viscosity
A
- Changes during mixing but returns to its original state after mixing
11
Q
- Mixing in stirred tank reactors can
A
- All of the above
12
Q
- In animal cell bioreactor, bubble damage can be minimized by
A
- All of the above
13
Q
- 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
A
- Thixotropic
14
Q
- In sparged mammalian cell bioreactors, the cell damage is caused because of
A
- All of the above
15
Q
- The SI unit for viscosity is
A
- kg.m-1.s-1
16
Q
- The viscous nature of a non-Newtonian fluid
A
- Changes with the level of power input and/or the length of time during which the fluid is mixed
17
Q
- Which of the following compound, if added to a solution will lead to the greatest increase in viscosity?
A
- A long chain protein such as albumin
18
Q
- A Brookfield viscometer measures viscosity by determining
A
- The torque required to move an impeller at a set speed
19
Q
- Which of the following factors will affect the sensitivity of animal cells to shear conditions?
A
- All of the above
20
Q
- The best described action of Pluronic F68 (non-ionic detergent) in a cell culture medium is that, it
A
- Acts on the surface properties of the cells and the culture medium
21
Q
- Water is a
A
- Newtonian fluid
22
Q
- Which of the following affect the Kolmogorov eddy size?
A
- All of these
23
Q
- 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
A
- Turbulent phase
24
Q
- The viscosity of a fluid increases with the length of time that it is being mixed. This fluid would be best described as being
A
- Rheopectic
25
Q
- Which of the following can act as a shear protectorant?
A
- Serum
26
Q
- The viscosity of a fluid increases with increasing stirrer speed. This fluid would be best described as being
A
- Dilatant
27
Q
- A dilatant fluid is one in which the viscosity
A
- Increases with increasing stirrer speed
28
Q
- A rheopectic fluid is one in which the viscosity
A
- Increases with mixing time
29
Q
- A fluid in which the viscosity increases with increasing stirrer speed and mixing time can be called as
A
- Dilatant, rheopectic fluid
30
Q
- The medium will have the highest viscosity (considering that the cells do not secrete gums) with the presence of
A
- Filamentous fungi that grow as long poorly branched chains
31
Q
- A Newtonian fluid is one in which the viscosity
A
- Is constant regardless of the stirrer speed or mixing time
32
Q
- Which pattern of mixing is preferred in stirred tank reactors during the culture of aerobic microorganisms?
A
- Turbulent flow
33
Q
- Animal cell cultures do not have much effect on shear forces because
A
- The cell size is generally smaller than the critical eddy size at which shear will have an effect
34
Q
- The viscosity of the culture fluid is classified as both pseudoplastic and thixotropic which indicates that the viscosity
A
- Decreases with stirring speed and decreases with mixing time
35
Q
- Pluronic F68 is added to cell culture media as
A
- A shear protectorant
36
Q
- A stirred tank reactor containing a fluid with a density of 2.5 g.ml-1 and viscosity of 0.002 kg m-1s-1 is mixed at 120 rpm. If the fluid is mixed with an impeller having diameter 50 cm, then the Reynolds number of the liquid in the reactor is
A
- 12,50,000
37
Q
- If the viscosity of a fluid decreases with the length of time that it is being mixed, then this fluid is
A
- Thixotropic
38
Q
- Which of the following describes the importance of the Kolmogorov eddy size in the biotechnology?
A
- All of the above
39
Q
- A thixotropic fluid is one in which the viscosity
A
- Decreases with mixing time
40
Q
- Newtonian fluid is one in which the viscosity
A
- Remains constant with time and power input
41
Q
- Reynolds number for laminar flow over a plate should be less than
A
- 5×1055×105
42
Q
- The approach which is commonly used to determine the level of damage to animal cells in a culture medium is to monitor
A
- The level of lactate dehydrogenase activity
43
Q
- A Brookfield viscometer cannot determine the shear stress because
A
- The impeller type is given only by numbers
44
Q
- Which of the following is correct?
A
- The viscosity of gases decreases with increasing temperature, but decreases in liquids
45
Q
- The Komologorov eddy size
A
- Decreases with stirrer speed
46
Q
- Pluronic F68 protects mammalian cells from damage stems as it is a/an
A
- Surface active agent which stabilizes foams
47
Q
- Reynolds number for turbulent flow over a plate should be more than
A
- 5×1055×105
