Growth of animal cells in culture MCQs With Answer is an essential study area for B. Pharm students focusing on in vitro cell growth, cell line maintenance, and experimental techniques. This introduction covers key concepts such as primary culture vs. cell lines, growth phases, culture media composition, serum and growth factors, aseptic techniques, incubation conditions, contamination control, and viability assays. These topics support formulation development, cytotoxicity testing, and biopharmaceutical research. The following MCQs emphasize practical understanding—cell counting, doubling time, passaging, cryopreservation, and analytical methods—that B. Pharm students must master for laboratory competency. Now let’s test your knowledge with 50 MCQs on this topic.
Q1. What is the primary difference between primary cultures and established cell lines?
- Primary cultures are derived directly from tissues and have limited lifespan
- Established cell lines always originate from bacterial contamination
- Primary cultures are immortal and can be passaged indefinitely
- Established cell lines cannot be used for drug testing
Correct Answer: Primary cultures are derived directly from tissues and have limited lifespan
Q2. Which phase of cell growth in batch culture shows the highest rate of cell division?
- Lag phase
- Exponential (log) phase
- Stationary phase
- Decline phase
Correct Answer: Exponential (log) phase
Q3. Which component of culture media is the major source of growth factors and hormones?
- Tris buffer
- Fetal bovine serum (FBS)
- Sodium chloride
- EDTA
Correct Answer: Fetal bovine serum (FBS)
Q4. What is the function of trypsin in adherent cell culture?
- To stain dead cells for counting
- To digest extracellular matrix proteins for detaching cells
- To increase CO2 concentration in incubator
- To act as a cryoprotectant during freezing
Correct Answer: To digest extracellular matrix proteins for detaching cells
Q5. Which method is commonly used to measure viable cell number by dye exclusion?
- MTT assay
- Trypan blue and hemocytometer
- PCR quantification
- Spectrophotometric OD260 reading
Correct Answer: Trypan blue and hemocytometer
Q6. What is “doubling time” in cell culture?
- The time required for the cell population to reduce by half
- The time required for a single cell to divide once
- The time required for the population to double in number
- The time needed to thaw frozen cells
Correct Answer: The time required for the population to double in number
Q7. Which incubation condition is most important for maintaining pH in bicarbonate-buffered media?
- Humidity level
- CO2 concentration
- Light intensity
- Oxygen saturation at 100%
Correct Answer: CO2 concentration
Q8. What is contact inhibition in cultured cells?
- Cells stop dividing when they reach confluence due to cell-cell contact
- Cells increase division rate when crowded
- Cells die immediately upon contact with the surface
- Cells become resistant to antibiotics after contact
Correct Answer: Cells stop dividing when they reach confluence due to cell-cell contact
Q9. Which assay measures mitochondrial metabolic activity as a proxy for cell viability?
- Hemocytometer counting
- MTT or MTS assay
- Trypsinization assay
- Gram staining
Correct Answer: MTT or MTS assay
Q10. Which cryoprotectant is most commonly used for freezing animal cells?
- Glycerol at 20%
- DMSO (dimethyl sulfoxide) at ~10%
- Formaldehyde
- EDTA
Correct Answer: DMSO (dimethyl sulfoxide) at ~10%
Q11. What causes mycoplasma contamination in cell cultures?
- Improper CO2 levels
- Small bacterial contaminants lacking cell walls often introduced via reagents or personnel
- Too much serum in media
- Overuse of trypsin
Correct Answer: Small bacterial contaminants lacking cell walls often introduced via reagents or personnel
Q12. Which property distinguishes immortalized cell lines from primary cells?
- Immortalized lines require serum to grow
- Immortalized lines can proliferate indefinitely under proper conditions
- Primary cells are typically tumor-derived
- Immortalized cells cannot be frozen
Correct Answer: Immortalized lines can proliferate indefinitely under proper conditions
Q13. What is plating efficiency?
- Percentage of seeded cells that attach and form colonies
- Rate of contamination in culture
- Proportion of dead cells after freezing
- Volume of medium needed per flask
Correct Answer: Percentage of seeded cells that attach and form colonies
Q14. Which measurement estimates cell proliferation by DNA synthesis?
- Trypan blue exclusion
- BrdU or EdU incorporation assay
- Gram staining
- pH indicator test
Correct Answer: BrdU or EdU incorporation assay
Q15. Why is aseptic technique critical in animal cell culture?
- To promote bacterial growth intentionally
- To prevent contamination that can outcompete or harm cultured cells and alter experimental results
- To change cell morphology faster
- To increase osmolarity of media
Correct Answer: To prevent contamination that can outcompete or harm cultured cells and alter experimental results
Q16. What is anchorage dependence?
- Cells require a surface for attachment to grow and divide
- Cells grow only in suspension
- Cells need antibiotics to attach
- Cells attach only to plastic in the presence of serum
Correct Answer: Cells require a surface for attachment to grow and divide
Q17. Which buffer is commonly used in culture media to maintain pH besides bicarbonate?
- HEPES
- Acetic acid
- Sodium hydroxide
- SDS
Correct Answer: HEPES
Q18. What is confluence in cell culture terminology?
- The percentage of the incubation time completed
- The proportion of the surface area covered by adherent cells
- The concentration of CO2 in incubator
- Amount of serum required per dish
Correct Answer: The proportion of the surface area covered by adherent cells
Q19. Which antibiotic is commonly used in culture media to prevent bacterial contamination?
- Penicillin-streptomycin
- Ibuprofen
- Acetaminophen
- Insulin
Correct Answer: Penicillin-streptomycin
Q20. How does serum-free media benefit specific applications?
- It removes variability from animal serum, enabling defined conditions and better reproducibility
- It always increases cell growth regardless of cell type
- It sterilizes cultures automatically
- It prevents the need for CO2 control
Correct Answer: It removes variability from animal serum, enabling defined conditions and better reproducibility
Q21. What is the primary goal of subculturing (passaging) adherent cells?
- To increase contamination risk
- To prevent overconfluence and maintain cells in exponential growth
- To change the genetic make-up of cells
- To permanently stop cell division
Correct Answer: To prevent overconfluence and maintain cells in exponential growth
Q22. Which instrument is used for automated cell counting and viability assessment using fluorescence?
- Hemocytometer only
- Automated cell counter/flow cytometer
- pH meter
- Autoclave
Correct Answer: Automated cell counter/flow cytometer
Q23. What is trypan blue used for in cell culture assays?
- To stimulate cell division
- To dye and identify dead cells because it penetrates compromised membranes
- To enhance protein synthesis
- To prevent bacterial growth
Correct Answer: To dye and identify dead cells because it penetrates compromised membranes
Q24. Which factor most directly influences osmolarity of culture medium?
- Antibiotic concentration
- Sodium chloride and solute concentration
- Incubator humidity
- Type of plasticware
Correct Answer: Sodium chloride and solute concentration
Q25. What is the main purpose of using CO2 incubators in mammalian cell culture?
- To maintain temperature only
- To regulate both temperature and CO2 for bicarbonate buffer pH control
- To sterilize equipment
- To measure cell density
Correct Answer: To regulate both temperature and CO2 for bicarbonate buffer pH control
Q26. Which assay specifically quantifies viable cells by conversion of tetrazolium salts to formazan?
- MTT assay
- Gram stain
- Western blot
- PCR
Correct Answer: MTT assay
Q27. Why is slow cooling at about 1°C/min important during cryopreservation?
- It ensures rapid ice crystal formation inside cells
- It minimizes intracellular ice formation and osmotic shock, improving survival
- It accelerates thawing
- It increases contaminant growth
Correct Answer: It minimizes intracellular ice formation and osmotic shock, improving survival
Q28. Which contamination is often invisible under light microscopy but affects culture growth and metabolism?
- Fungal hyphae
- Mycoplasma
- Large bacterial colonies
- Algal overgrowth
Correct Answer: Mycoplasma
Q29. What is the effect of high passage number on cell lines?
- Cells become more identical to donor tissue
- Genetic drift, phenotypic changes, and possible loss of functionality
- Passage number has no impact
- Cells become resistant to low temperatures
Correct Answer: Genetic drift, phenotypic changes, and possible loss of functionality
Q30. Which method is best for detecting mycoplasma contamination?
- Visual inspection of media only
- PCR-based mycoplasma detection or specific biochemical assays
- Measuring pH only
- Trypsinization test
Correct Answer: PCR-based mycoplasma detection or specific biochemical assays
Q31. What does “serum supplementation” provide to culture media?
- Only antibiotics
- Growth factors, hormones, attachment factors, and binding proteins
- Pure glucose exclusively
- Sterility guarantee
Correct Answer: Growth factors, hormones, attachment factors, and binding proteins
Q32. Which parameter is commonly used to monitor cell culture contamination by bacteria or fungi?
- Change in media color or turbidity
- Decrease in incubator temperature
- Increase in serum concentration
- Cell freezing
Correct Answer: Change in media color or turbidity
Q33. In cell culture, what does synchronization of cells refer to?
- Keeping all cells at the same confluence level
- Aligning cells to the same cell cycle phase for experimental consistency
- Freezing and thawing cells simultaneously
- Adding antibiotics at the same time each day
Correct Answer: Aligning cells to the same cell cycle phase for experimental consistency
Q34. Which culture system is suitable for large-scale production of cells in suspension?
- Microtiter plates only
- Bioreactors designed for suspension cultures
- Static flasks without agitation
- Gel electrophoresis chambers
Correct Answer: Bioreactors designed for suspension cultures
Q35. What is the main role of L-glutamine in culture media?
- Acts as an osmotic agent
- Provides a labile nitrogen source and energy for rapidly dividing cells
- Functions as a cryoprotectant
- Prevents pH changes
Correct Answer: Provides a labile nitrogen source and energy for rapidly dividing cells
Q36. Why are antibiotics sometimes avoided in routine cell culture?
- They always kill mammalian cells
- They can mask low-level contamination and promote resistant organisms; aseptic technique is preferred
- They reduce CO2 levels
- They increase cell doubling time universally
Correct Answer: They can mask low-level contamination and promote resistant organisms; aseptic technique is preferred
Q37. What is the purpose of using phenol red in culture media?
- To serve as a pH indicator
- To kill microbes
- To promote cell adhesion
- To increase osmolarity
Correct Answer: To serve as a pH indicator
Q38. Which of the following best describes anchorage-independent growth?
- Cells that require attachment to proliferate
- Cells that can grow in suspension, often an indicator of transformation or tumorigenicity
- Cells that cannot survive in any medium
- Cells that only grow on glass surfaces
Correct Answer: Cells that can grow in suspension, often an indicator of transformation or tumorigenicity
Q39. What is the key consideration when thawing frozen cell vials rapidly?
- To prevent thermal shock by slow warming
- To quickly thaw in a 37°C water bath to minimize ice recrystallization and osmotic damage
- To keep the vial frozen while opening
- To expose cells to room air for 30 minutes
Correct Answer: To quickly thaw in a 37°C water bath to minimize ice recrystallization and osmotic damage
Q40. What does a clonogenic (colony-forming) assay measure?
- Short-term metabolic activity only
- Ability of a single cell to survive and proliferate into a colony over time
- Concentration of antibiotics required
- Number of dead cells after staining
Correct Answer: Ability of a single cell to survive and proliferate into a colony over time
Q41. Which factor can accelerate cellular senescence in vitro?
- Low oxygen tension only
- High oxidative stress and repeated passaging
- Appropriate cryopreservation
- Use of serum-free media exclusively
Correct Answer: High oxidative stress and repeated passaging
Q42. What is the advantage of using serum substitutes or defined media?
- They are always cheaper than serum
- They provide known components reducing variability for mechanistic studies and regulatory compliance
- They eliminate need for sterile technique
- They increase contaminant resistance
Correct Answer: They provide known components reducing variability for mechanistic studies and regulatory compliance
Q43. Which parameter is NOT typically monitored to assess culture health?
- Cell morphology and adherence
- pH and media color
- Doubling time and viability
- Ambient room noise level
Correct Answer: Ambient room noise level
Q44. How does serum starvation synchronize cells?
- By causing immediate apoptosis of all cells
- By depriving growth factors so cells accumulate in G0/G1 and can be re-stimulated synchronously
- By increasing temperature to halt division
- By adding excess glucose to block the cell cycle
Correct Answer: By depriving growth factors so cells accumulate in G0/G1 and can be re-stimulated synchronously
Q45. Which way is best to prevent cross-contamination between cell lines?
- Use the same pipette tips for all lines
- Work with one cell line at a time, label clearly, use separate media aliquots and proper aseptic handling
- Mix cell lines intentionally to reduce contamination
- Store all lines in one thawed tube
Correct Answer: Work with one cell line at a time, label clearly, use separate media aliquots and proper aseptic handling
Q46. What is the role of growth factors in culture media?
- They are antibiotics to kill microbes
- They bind to receptors and stimulate proliferation, survival, or differentiation pathways
- They act as buffers for pH
- They increase osmolarity only
Correct Answer: They bind to receptors and stimulate proliferation, survival, or differentiation pathways
Q47. Which technique quantifies cell cycle distribution by DNA content?
- Western blotting
- Flow cytometry with DNA-binding dyes (e.g., propidium iodide)
- Colony counting only
- Phase-contrast microscopy without staining
Correct Answer: Flow cytometry with DNA-binding dyes (e.g., propidium iodide)
Q48. Why is it important to validate cell line identity periodically?
- To confirm cell morphology changes are permanent
- To ensure experimental reproducibility and avoid misidentified or cross-contaminated lines using STR profiling or other methods
- To increase growth rate artificially
- To eliminate the need for sterile technique
Correct Answer: To ensure experimental reproducibility and avoid misidentified or cross-contaminated lines using STR profiling or other methods
Q49. Which condition would most likely reduce cell proliferation?
- Optimized nutrient-rich media
- Hypothermic culture at low temperature (e.g., 20°C)
- Supplementation with essential growth factors
- Maintaining physiological pH and temperature
Correct Answer: Hypothermic culture at low temperature (e.g., 20°C)
Q50. What is the purpose of performing a viability assay before an experiment?
- To determine the proportion of living cells and ensure reproducible starting conditions for experiments
- To sterilize the cell suspension
- To change the cell genotype
- To increase serum requirement
Correct Answer: To determine the proportion of living cells and ensure reproducible starting conditions for experiments
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