What is the primary limitation of primary cell cultures compared to continuous cell lines?
Answer: B
Primary cells have limited replicative lifespan due to the Hayflick limit and may undergo changes over passages, whereas continuous cell lines can divide indefinitely.
Q.2Hard
A researcher observes that their CHO (Chinese Hamster Ovary) cell culture shows reduced protein production despite maintaining normal cell density. What could be the most likely cause?
Answer: B
Even at normal density, cells require optimal osmolarity (280-320 mOsm/kg) and adequate nutrients. Nutrient depletion reduces metabolic activity and protein synthesis despite maintained cell count.
Q.3Hard
In the context of vaccine production using cell culture, which cell lines are most commonly used in India?
Answer: B
Vero (monkey kidney), CHO (hamster ovary), and HEK293 (human embryonic kidney) cells are widely used for vaccine production including COVID-19 and other vaccines in India.
Q.4Hard
Which of the following represents the correct sequence in scaling up cell culture from laboratory to industrial bioreactor?
Answer: A
Scale-up follows a logical progression from small (flask) to larger volumes, with each step validated for maintaining cell viability, growth rate, and product quality.
Q.5Hard
What is the significance of mycoplasma testing in cell culture quality control for biopharmaceutical production?
Answer: C
Mycoplasma is an obligatory contaminant in cell cultures that can affect cell behavior and product quality. Detection via PCR, culture, or ELISA is mandatory in biopharmaceutical manufacturing per ICH guidelines.
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Q.6Hard
In a perfusion bioreactor system used for continuous cell culture, what is the primary advantage over batch culture?
Answer: B
Perfusion systems continuously exchange medium, removing metabolic wastes and supplying nutrients, enabling higher cell densities and prolonged culture periods compared to batch systems.
Q.7Hard
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.8Hard
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.9Hard
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.10Hard
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.11Hard
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.
Q.12Hard
How does dissolved oxygen concentration affect cell culture performance?
Answer: C
While cells need oxygen for respiration, excessive DO can cause oxidative stress. Moderate DO levels (30-50% saturation) optimize growth and reduce lactate accumulation.
Q.13Hard
What is the significance of glucose/lactate ratio monitoring in cell culture?
Answer: A
The glucose consumption rate and lactate production rate indicate metabolic efficiency. High lactate accumulation suggests metabolic stress and can inhibit cell growth.
Q.14Hard
In the 2024-25 era of cell culture, what emerging trend is being adopted by Indian biotech companies?
Answer: B
Modern Indian biotech (2024-25) is shifting toward single-use bioreactors for flexibility, ACF/serum-free media for safety, and automation for consistency in line with global standards.
Q.15Hard
Which parameter is MOST critical to monitor in a GMP-compliant mammalian cell culture facility?
Answer: B
GMP compliance requires continuous monitoring of critical quality attributes (CQAs): viable cell density, viability percentage, and product titer. Real-time monitoring ensures batch consistency and safety.
