Cell culture techniques: equipment and media MCQs With Answer

Introduction:

This quiz set on Cell culture techniques: equipment and media is designed for M.Pharm students preparing for advanced examinations and practical lab work. It focuses on critical aspects of cell culture: incubators, biosafety cabinets, filtration, cryopreservation, basal media, serum and serum-free formulations, buffers, sterility controls and monitoring techniques. Questions emphasize applied knowledge—why equipment specifications matter, how media components influence cell physiology, and best practices for aseptic technique and large-scale culture. These MCQs go beyond definitions to test decision-making relevant to experimental design, troubleshooting contamination, and selecting appropriate media and equipment for specific cell culture applications.

Q1. What is the primary reason a CO2 incubator is used for culturing mammalian cells?

• Maintain a constant 37°C for mammalian cells
• Control CO2 concentration to maintain bicarbonate-buffered media pH
• Provide aseptic laminar airflow to prevent contamination
• Remove volatile organic compounds via activated charcoal

Correct Answer: Control CO2 concentration to maintain bicarbonate-buffered media pH

Q2. Which class of biological safety cabinet provides both product and personnel protection while allowing open work access?

• Class I BSC (personnel protection only)
• Class II BSC (product and personnel protection)
• Class III BSC (totally enclosed, glove box)
• Clean bench (product protection only)

Correct Answer: Class II BSC (product and personnel protection)

Q3. What is the role of phenol red in most tissue culture media?

• Act as an antioxidant to protect cells from oxidative stress
• Serve as a pH indicator to monitor culture medium acidity/alkalinity
• Provide essential vitamins for cell growth
• Stabilize dissolved oxygen concentration in medium

Correct Answer: Serve as a pH indicator to monitor culture medium acidity/alkalinity

Q4. Which basal medium is classically preferred for primary hepatocyte culture due to its composition?

• DMEM (Dulbecco’s Modified Eagle Medium)
• RPMI 1640
• L-15 (Leibovitz)
• Williams’ Medium E

Correct Answer: Williams’ Medium E

Q5. Which of the following best describes the major functional contributions of fetal bovine serum (FBS) in culture?

• Provide proteases to facilitate cell detachment
• Adjust osmolarity and buffer capacity of media
• Supply growth factors, attachment factors, and hormones
• Act as the primary energy source for cultured cells

Correct Answer: Supply growth factors, attachment factors, and hormones

Q6. What is the routine FBS concentration commonly used for maintaining many adherent mammalian cell lines?

• 0.5% FBS
• 2% FBS
• 10% FBS
• 30% FBS

Correct Answer: 10% FBS

Q7. Which filter pore size is commonly used to sterilize cell culture media by removing bacteria?

• 0.45 µm
• 0.22 µm
• 0.10 µm
• 0.80 µm

Correct Answer: 0.22 µm

Q8. What is the standard cryoprotectant and typical concentration used for freezing mammalian cells for long-term storage?

• 10% ethanol in PBS
• 10% DMSO in serum-containing medium
• 50% glycerol in water
• 5% sodium chloride solution

Correct Answer: 10% DMSO in serum-containing medium

Q9. How does trypsin-EDTA detach adherent cells from culture surfaces?

• EDTA dissolves extracellular matrix; trypsin stabilizes cell membranes
• Trypsin chelates divalent cations while EDTA proteolyzes adhesion proteins
• Trypsin proteolytically cleaves adhesion proteins and EDTA chelates Ca2+/Mg2+ to weaken cell–cell and cell–substrate interactions
• They both fix the cells to allow mechanical scraping

Correct Answer: Trypsin proteolytically cleaves adhesion proteins and EDTA chelates Ca2+/Mg2+ to weaken cell–cell and cell–substrate interactions

Q10. Which method is considered most sensitive for routine detection of mycoplasma contamination in cell cultures?

• Gram staining of culture supernatant
• PCR-based mycoplasma detection assays
• Measuring turbidity of culture medium
• Visual inspection under phase-contrast microscopy alone

Correct Answer: PCR-based mycoplasma detection assays

Q11. Which media component or additive is commonly used as a non-CO2-dependent buffer to stabilize pH during manipulations outside a CO2 incubator?

• Sodium bicarbonate alone
• HEPES buffer
• Phenol red dye
• EDTA

Correct Answer: HEPES buffer

Q12. HEPA filters used in biosafety cabinets are rated to remove particles down to which size with ~99.97% efficiency?

• 1.0 µm
• 0.3 µm
• 0.05 µm
• 5.0 µm

Correct Answer: 0.3 µm

Q13. What is the main advantage of switching from serum-containing to serum-free, chemically defined media?

• All cell types grow faster in serum-free media without optimization
• Eliminates batch-to-batch variability and allows defined supplementation
• Removes the need for antibiotics
• Prevents adherence of cells to culture plastic

Correct Answer: Eliminates batch-to-batch variability and allows defined supplementation

Q14. What is the typical osmolarity range recommended for mammalian cell culture media?

• ~150 mOsm/kg
• ~300 mOsm/kg
• ~450 mOsm/kg
• ~600 mOsm/kg

Correct Answer: ~300 mOsm/kg

Q15. Which buffering system is most suitable for experiments performed outside a CO2 incubator when CO2 control is not available?

• Bicarbonate buffer alone
• HEPES buffering system
• Phosphate-buffered saline (PBS) as a culture base
• Sodium acetate buffer

Correct Answer: HEPES buffering system

Q16. Why is tissue culture-treated plastic used for adherent cells?

• The treatment sterilizes the plastic surface
• Treated plastic increases hydrophilicity and adds charged groups to promote cell attachment
• Treated plastic slowly releases growth factors
• Treated plastic prevents protein adsorption

Correct Answer: Treated plastic increases hydrophilicity and adds charged groups to promote cell attachment

Q17. Roller bottles or multilayer flasks are primarily used in adherent cell culture to achieve what purpose?

• Allow efficient suspension growth without microcarriers
• Provide very high surface area-to-volume ratio for large-scale adherent cell expansion
• Enhance gas exchange for hypoxic experiments only
• Reduce shear stress to zero during rapid stirring

Correct Answer: Provide very high surface area-to-volume ratio for large-scale adherent cell expansion

Q18. What are the typical working concentrations for penicillin and streptomycin in routine cell culture antibiotic supplementation?

• Penicillin 100 U/mL and streptomycin 100 µg/mL
• Penicillin 1000 U/mL and streptomycin 1000 µg/mL
• Penicillin 1 U/mL and streptomycin 1 µg/mL
• Penicillin 10 U/mL and streptomycin 10 µg/mL

Correct Answer: Penicillin 100 U/mL and streptomycin 100 µg/mL

Q19. What is the recommended cooling rate when freezing typical mammalian cells for cryopreservation to minimize intracellular ice formation?

• Rapid plunge to -196°C (liquid nitrogen) without controlled cooling
• Approximately -1°C per minute down to -80°C before transfer to liquid nitrogen
• Approximately -10°C per minute to -80°C
• Slow cooling at +1°C per minute to room temperature

Correct Answer: Approximately -1°C per minute down to -80°C before transfer to liquid nitrogen

Q20. What is the purpose of microcarrier beads in stirred-tank bioreactors for adherent cell lines?

• To enable suspension growth of inherently non-adherent cells
• To increase available surface area so adherent cells can be grown in stirred suspension systems
• To decrease dissolved oxygen levels around cells
• To serve as cryoprotectants during freezing

Correct Answer: To increase available surface area so adherent cells can be grown in stirred suspension systems

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