Which growth factor is primarily responsible for promoting cell proliferation in mammalian cell culture media?
Answer: A
EGF is a primary mitogenic growth factor that stimulates cell proliferation. While other factors support cell survival, EGF is specifically responsible for promoting cell division in mammalian cultures.
Q.222Easy
What is the primary purpose of using serum-free media (SFM) in industrial cell culture?
Answer: B
Serum-free media reduce lot-to-lot variability of serum batches, improve product purity, and simplify downstream purification processes, making them essential for pharmaceutical production.
Q.223Easy
Which of the following cell lines is commonly used for monoclonal antibody production?
Answer: B
Myeloma cell lines (NSO or SP02) are immortal cells used to create hybridomas through fusion with B lymphocytes for monoclonal antibody production.
Q.224Easy
The doubling time of mammalian cells cultured in vitro typically ranges between:
Answer: B
Most mammalian cell lines have doubling times of 12-24 hours under optimal culture conditions. Bacterial doubling times are much shorter (2-4 hours).
Q.225Medium
Which parameter is most critical for maintaining pH stability in a large-scale bioreactor?
Answer: B
The bicarbonate-CO₂ buffering system is essential in bioreactors to maintain physiological pH (around 7.2-7.4) as cells metabolize nutrients and produce waste products.
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Q.226Medium
What is the significance of cryopreservation in cell culture banking?
Answer: B
Cryopreservation using liquid nitrogen or cryoprotectants like DMSO allows cells to be stored long-term while maintaining viability and genetic stability for future use.
Q.227Medium
In the context of Indian pharmaceutical biotech (2024-25), which cell line is most commonly used for recombinant protein production?
Answer: A
CHO cells are the industry standard for recombinant protein production due to their high productivity, proper protein glycosylation, and regulatory acceptance globally and in India.
Q.228Medium
Which of the following best describes the G0 phase in the cell cycle?
Answer: C
G0 (G-zero) represents the quiescent state where cells are metabolically active but not dividing. Cells can exit G1 phase and enter G0 under nutrient limitation or other stress conditions.
Q.229Medium
What is the primary advantage of using suspension culture systems over adherent culture for large-scale production?
Answer: B
Suspension cultures allow cells to grow at higher densities (up to 10^7-10^8 cells/mL) and are easily scalable in bioreactors, making them ideal for industrial production.
Q.230Medium
During scale-up of cell culture from 2L to 200L bioreactor, which parameter becomes increasingly challenging to maintain?
Answer: B
As bioreactor volume increases, maintaining uniform oxygen distribution and adequate mixing becomes exponentially more difficult, requiring optimized agitation and aeration strategies.
Q.231Easy
Which disinfectant is most commonly used for sterilizing bioreactor surfaces and cell culture equipment?
Answer: A
70% ethanol is the standard disinfectant for cell culture work due to its effectiveness against most microorganisms and minimal residual toxicity to cells.
Q.232Medium
What is the primary function of osmolarity/osmotic pressure control in cell culture media?
Answer: B
Proper osmolarity (typically 280-320 mOsm/kg) maintains isotonic conditions, preventing cell swelling (hypotonic) or shrinkage (hypertonic), which would lead to cell damage.
Q.233Medium
In viral vaccine production using cell culture, which cell line is commonly used for influenza vaccine manufacturing?
Answer: A
MDCK cells are widely used for influenza virus propagation and vaccine production. They support high-titer viral replication and are approved for vaccine manufacturing.
Q.234Medium
What is the role of trypsin in cell culture preparation and maintenance?
Answer: B
Trypsin (0.05% typically) is a serine protease that digests proteins binding cells to culture vessels, allowing gentle detachment of adherent cells for subculturing.
Q.235Medium
Which of the following statements about lactate production in mammalian cell culture is correct?
Answer: B
Lactate accumulates as a metabolic byproduct and at concentrations >15-20 mM can inhibit cell growth and reduce productivity. Lactate management is crucial in fed-batch cultures.
Q.236Hard
What is the significance of using antifoam agents in large-scale bioreactors?
Answer: B
Foam formation in bioreactors during aeration can cause cell lysis, loss of surface area, and carryover into exhaust lines. Antifoam agents (silicone-based) prevent this.
Q.237Hard
In the fed-batch culture strategy, the primary advantage over batch culture is:
Answer: B
Fed-batch feeding strategies prevent nutrient depletion and byproduct accumulation, extending productive culture phases and improving final product titers compared to batch culture.
Q.238Hard
Which method is most suitable for real-time monitoring of cell viability in a bioreactor during fermentation?
Answer: B
Dielectric spectroscopy provides real-time, non-invasive measurement of viable cell density by measuring membrane capacitance, enabling immediate process adjustments.
Q.239Hard
For Indian biotech industries (2024-25) producing therapeutic monoclonal antibodies, which regulatory requirement regarding cell line characterization is mandatory?
Answer: B
ICH Q5A/Q5B guidelines (followed by India's DCGI) mandate comprehensive cell line characterization including identity verification, sterility, mycoplasma, and viral testing for therapeutic products.
Q.240Hard
What is the consequence of exceeding the maximum viable cell density (MVCD) in a culture system?
Answer: B
Beyond MVCD, limited oxygen, glucose depletion, and accumulation of lactate/ammonia create hostile conditions triggering the decline phase with apoptosis and decreased productivity.
