Bioprocess Engineering Multiple Choice Questions on “Bioreactor Considerations”.
1. In tissue culture media which ions inhibit trypsin from the following?
A. Na+
B. Pb2+
C. Mg2+
D. Fe2+
Answer: C
Explanation: Tissue culture media contains calcium and magnesium ions, fetal bovine serum contains proteins that are trypsin inhibitors. Both Mg2+ and Ca2+ inhibit trypsin. To weaken the function of adhesion molecules.
2. EDTA function as_________
A. Divalent cations chelator
B. Divalent anion chelator
C. Monovalent cation chelator
D. Monovalent anion chelator
Answer: A
Explanation: EDTA is frequently included in the trypsin solution for its function as divalent cations chelator.
3. EDTA is carcinogenic.
A. True
B. False
Answer: B
Explanation: The typical concentration of use of EDTA is less than 2%, with the other salts in current use at even lower concentrations. The lowest dose reported to cause a toxic effect in animals was 750 mg/kg/day. These chelating agents are cytotoxic and weakly genotoxic, but not carcinogenic.
4. Spinner flask contains:
A. Spindle shaped agitators
B. Cylindrical agitators
C. Simple agitators
D. Spoon-like agitators
Answer: D
Explanation: Spinner flasks contain a magnetically driven impeller or spoonlike agitators that operate at 10 to 60 rpm. Aeration is usually by surface aeration using 5% CO2-enriched and filtered air for mammalian cell lines. Spinner flasks are set on a magnetic stirrer plate in a CO2 incubator.
5. What do you mean by microcarrier?
A. Carrier of small molecules
B. Carrier of small cells
C. Support material of suspended cells
D. Support material of adherent cells
Answer: D
Explanation: A microcarrier is a support matrix allowing for the growth of adherent cells in bioreactors. Microcarriers are regularly used to grow protein-producing or virus-generating adherent cell populations in the large-scale commercial production of biologics (proteins) and vaccines.
6. Membrane bioreactor is the combination of microfiltration and ultrafiltration.
A. True
B. False
Answer: A
Explanation: Membrane bioreactor (MBR) is the combination of a membrane process like microfiltration or ultrafiltration with a biological wastewater treatment process, the activated sludge process. It is now widely used for municipal and industrial wastewater treatment.
7. In microencapsulation which of the coating materials is not used for coating:
A. Sodium alginate
B. Sodium chloride
C. Gelatin
D. Polyvinyl alcohol
Answer: B
Explanation: The coating materials generally used for coating are:
▪ Ethyl cellulose
▪ Polyvinyl alcohol
▪ Gelatin
▪ Sodium alginate
The definition has been expanded, and includes most foods, where the encapsulation of flavors is the most common. The technique of microencapsulation depends on the physical and chemical properties of the material to be encapsulated.
8. What do you mean by spent medium?
A. Medium with high nutritional content
B. Hydrated
C. Dehydrated
D. Non-toxic
Answer: C
Explanation: After each sub-culture, the medium is discarded because it has been depleted of nutrients, dehydrated or accumulated toxic metabolic products.
9. In relation to surface area roller bottles are less advantageous than T-Flask.
A. True
B. False
Answer: B
Explanation: The roller-bottle system has an advantage over T-flasks because of increased surface area, agitation of the liquid, and better aeration. Roller bottles are not typically used for large-scale production because of high labor requirements and bottle-to-bottle variability.
10. DEAE beads are negatively charged.
A. True
B. False
Answer: B
Explanation: Anion-exchange chromatography is a process that separates substances based on their charges using an ion-exchange resin containing positively charged groups, such as diethyl-aminoethyl groups (DEAE). In solution, the resin is coated with positively charged counter-ions (cations).
11. Hydrofoils give low turbulence.
A. True
B. False
Answer: A
Explanation: Propellers (marine or hydrofoil) give an inlet and outlet which are on axial direction, preferably downward, they are characterized by a nice pumping flow, low energy consumption and low shear magnitude as well as low turbulence.
12. The cells are prone to damage at which region?
A. Inside the gas bubble
B. Outside the medium
C. Interface of a gas bubble and medium
D. Inside the medium
Answer: C
Explanation: Only cells that are at the interface of an eddy and another eddy or another surface (e.g., reactor wall) are likely to experience damage. Cells at the gas–liquid interface are particularly prone to damage. The breakage of air bubbles is particularly destructive to cells that accumulate at the interface of a gas bubble and medium.
13. Pluronic F-68 is____________
A. Ionic
B. Non-ionic
C. Covalent
D. Metallic
Answer: B
Explanation: Poloxamers are nonionic triblock copolymers composed of a central hydrophobic chain of polyoxypropylene (poly(propylene oxide)) flanked by two hydrophilic chains of polyoxyethylene (poly(ethylene oxide)). Poloxamers are also known by the trade names Synperonics, Pluronics, and Kolliphor.
14. The accumulation of toxic metabolic products in beads is a problem of which of the following methods?
A. Gel beads
B. Microencapsulation
C. Tubular ceramic matrix
D. Roller bottles
Answer: A
Explanation: High cell densities make high volumetric productivities possible. However, the control of microenvironmental conditions inside bead particles and the accumulation of toxic metabolic products in beads are potential problems in the immobilization of mammalian cells in gel beads (agar, alginate, collagen, polyacrylamide).
15. Small bubbles are more shear sensitive than large bubbles.
A. True
B. False
Answer: B
Explanation: Animal cells are very shear sensitive, and rising air bubbles may cause shear damage to cells, particularly at the point of bubble rupture. Very small bubbles are less damaging.