Downstream Processing MCQs : This section focuses on the "Downstream Processing". These Multiple Choice Questions (MCQs) should be practiced to improve the Downstream Processing skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.
Question 1
Concentration polarization can be reduced further by
A. pre filtering the solution
B. reducing the flow rate per unit membrane surface area
C. back washing periodically
D. All of the above
Question 2
A system which require less solvent and produces a more concentrated extract phase, is desired with a
A. large distribution coefficients
B. small distribution coefficients
C. very small distribution coefficients
D. constant distribution coefficients
Question 3
The efficiency of cell disruption in a bead mill depends on the
A. concentration of the cells
B. amount and size of beads
C. type and rotational speed of agitation
D. All of the above
Question 4
A common filter medium is the cloth filter generally made of
A. canvas
B. synthetic fabrics
C. metal or glass fiber
D. All of the above
Question 5
An ion exchange resin is composed of
A. polymeric network
B. ionic functional groups
C. counter ions
D. All of the above
Question 6
Maintenance cost varies from
A. 0-4% of the capital cost
B. 12-16% of the capital cost
C. 4-8% of the capital cost
D. 8-12% of the capital cost
Question 7
The optimum wet solid content for the cell suspension for a bead mill is typically somewhere between
A. 5-15% by volume
B. 15-30% by volume
C. 30-60% by volume
D. 60-90% by volume
Question 8
Selectivity can be expressed as
A. ratio of the distribution coefficients in different solute
B. mass fraction of the solute in the extract phase at equilibrium
C. mass fraction of the solute in the raffinate phase
D. ratio of the mass fraction of the solute in the extract phase to the raffinate phase
Question 9
The disk centrifuge is the type of centrifuge used most often for bio separations due to its
A. continuous operation
B. lesser cost
C. higher speed
D. ease in operation
Question 10
The effectiveness of a solvent can be measured by the
A. distribution coefficients
B. selectivity
C. Both A and B
D. diffusivity
Question 11
The stage wise operation of adsorption is called
A. contact filtration
B. conventional adsorption
C. affinity adsorption
D. ion exchange
Question 12
Which of the following is not the physical method for the cells rupturing?
A. Milling
B. Homogenization
C. Ultrasonication
D. Enzymatic digestion
Question 13
Conventional adsorption is a
A. reversible process
B. irreversible process
C. either reversible or irreversible
D. None of the above
Question 14
If the solute passes through membrane freely, the the rejection coefficient (s) is
A. 1
B. 0
C. >1
D. <1
Question 15
If the membrane rejects all solute, the rejection coefficient (s) is
A. 1
B. 0
C. >1
D. <1
Question 16
In antibiotic manufacturing processes, the fermentation time ranges from
A. 2-3 weeks
B. 1-2 weeks
C. 4-5 weeks
D. 2-4 weeks
Question 17
The conventional filtration involves the separation of large particles generally
A. dp>5μm
B. dp>10μm
C. dp>15μm
D. dp>20μm
Question 18
Which of the operation does not come under upstream processing?
A. Media preparation
B. Inoculum development
C. Effluent treatment
D. Storage of raw material
Question 19
For cost analysis in a fermentor system, the depreciation cost varies from
A. 5-6% of the capital cost
B. 6-7% of the capital cost
C. 6-10% of the capital cost
D. 8-10% of the capital cost
Question 20
Micro filtration refers to the separation of suspended material such as bacteria by using a membrane with spore sizes of
A. 0.02 to 10μm
B. 1-10A°
C. 20-30μm
D. 10-200A°
Question 21
Start up expenses in a fermentation industry varies from
A. 0-5% of the capital cost
B. 10-15% of the capital cost
C. 5-10% of the capital cost
D. 15-20% of the capital cost
Question 22
Which of the following is considered as a pretreatment to the biological feeds?
A. Heating to denature the proteins
B. Addition of filter aids to increase the porosity
C. Addition of electrolytes
D. All of the above
Question 23
A common filter medium is the cloth filter generally made of
A. canvas
B. synthetic fabrics
C. metal or glass fiber
D. all of these
Question 24
A typical tubular centrifuge has a bowl of 2 to 5 inch in diameter and 9 to 30 inch in height with a maximum rotating speed of
A. 15,000 to 50,000 rpm
B. 50,000 to 100,000 rpm
C. 100,000 to 150,000 rpm
D. 150,000 to 200,000 rpm
Question 25
An ion exchange resin is composed of
A. polymeric network
B. ionic functional groups
C. counter ions
D. all of these
Question 26
Assuming the laminar flow across the filter, the rate of filtration (dVf/dt) can be expressed as a function of pressure drop Dp by the modified D'Arcy's equation as (where A is the area of filtering surface, K is the D'Arcy's filter cake permeability and L is the thickness of the filter cake)
A. (1/A) dVf/dt = Δp/μ(L/K)
B. dVf/dt = (1/A)Δp/μ(L/K)
C. (1/A) dVf/dt = Δp/μ LK
D. dVf/dt = (1/A)Δp/μ LK
Question 27
Chromatography is based on the
A. different rate of movement of the solute in the column
B. separation of one solute from other constituents by being captured on the adsorbent
C. different rate of movement of the solvent in the column
D. any of the above
Question 28
Conventional adsorption is a
A. reversible process
B. irreversible process
C. either reversible or irreversible
D. none of these
Question 29
Filtration leaf test results indicate that the filtration rate of a protein product is 100 dry lbs/(ft2 hr). What size production filter would be required to obtain 100 dry lbs of filter cake/hr?
A. 1.54 ft2
B. 3.08 ft2
C. 65 ft2
D. 65 lbs/ ft2.hr
Question 30
For the extractions operation, the selectivity should be
A. > 1
B. < 1
C. 1
D. zero
Question 31
The correlation often employed to correlate adsorption data for protein is (where Ymax is the maximum amount of solute adsorbed per mass of adsorbent, X is the mass fraction of solute in the diluent phase in solute-free basis, KL is a constant and Y is the equilibrium value of the mass of solute adsorbed per mass of adsorbent)
A. Y = YmaxX/(KL+X)
B. Y = Ymax/(KL+X)
C. Y = YmaxX/KL
D. Y = Ymax- X/ (KL+X)
Question 32
The effectiveness of a solvent can be measured by the
A. distribution coefficients
B. selectivity
C. both (a) and (b)
D. diffusivity
Question 33
The efficiency of cell disruption in a bead mill depends on the
A. concentration of the cells
B. amount and size of beads
C. type and rotational speed of agitation
D. all of these
Question 34
The purity of a solute collected between two times t1 and t2 during chromatographic separation can be calculated as
A. amount of solute eluted - amount of impurity eluted
B. amount of solute eluted / amount of impurity eluted
C. amount of solvent eluted + amount of impurity eluted
D. amount of solvent eluted / amount of impurity eluted
Question 35
The solvent flux across the membrane can be expressed as (where A is the area, Lp is the membrane permeability, σ is the reflection point, Δp is applied pressure and Δπ is the osmotic pressure)
A. J = Lp(Δp - σΔπ)
B. J/A = Lp(Δp - σΔπ)
C. J = Lp/σΔπ
D. J/A = Lp/Δp