Established cell cultures MCQs With Answer

Established cell cultures MCQs With Answer are essential study aids for B.Pharm students preparing for pharmacology, pharmaceutics, and biotechnology exams. This concise, keyword-rich introduction covers core concepts such as established cell lines, in vitro models, aseptic techniques, cell line characterization, culture maintenance, contamination control, cryopreservation, and cell authentication. Focused on practical knowledge and theory, these MCQs help strengthen understanding of growth kinetics, passaging, media formulation, viability assays, and biosafety practices. Practicing these questions boosts exam readiness and laboratory competence for future research or industry roles. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. What defines an established cell culture?

• A cell line continuously maintained and subcultured over many passages
• A freshly isolated primary culture from tissue
• A culture kept only for a single experiment
• A culture grown in non-sterile conditions

Correct Answer: A cell line continuously maintained and subcultured over many passages

Q2. Which of the following best distinguishes primary cultures from established cell lines?

• Primary cultures have finite lifespans; established cell lines are immortalized or adapted
• Primary cultures are always cancerous; established lines are normal
• Primary cultures grow faster than established cell lines
• Primary cultures require no aseptic technique

Correct Answer: Primary cultures have finite lifespans; established cell lines are immortalized or adapted

Q3. What is the main purpose of trypsinization in adherent cell cultures?

• To detach adherent cells for subculture
• To sterilize the culture flask
• To increase cell adherence
• To cryopreserve cells

Correct Answer: To detach adherent cells for subculture

Q4. Which parameter indicates the time required for a cell population to double?

• Doubling time
• Confluency
• Passage number
• Plating efficiency

Correct Answer: Doubling time

Q5. What is confluency in cell culture terms?

• The percentage of the growth surface covered by cells
• The concentration of serum in medium
• The number of contaminating bacteria
• The pH of the medium

Correct Answer: The percentage of the growth surface covered by cells

Q6. Which assay is commonly used to assess cell viability by metabolic activity?

• MTT assay
• Gram staining
• ELISA for cytokines
• Western blot

Correct Answer: MTT assay

Q7. What is the primary cryoprotectant used for freezing mammalian cells?

• Dimethyl sulfoxide (DMSO)
• Absolute ethanol
• Glycerol-free PBS
• Sodium hypochlorite

Correct Answer: Dimethyl sulfoxide (DMSO)

Q8. What is a master cell bank (MCB)?

• A well-characterized, thoroughly tested frozen stock used as a reference
• A culture grown only for a single experiment
• A contaminated stock discarded after use
• An untested primary isolate

Correct Answer: A well-characterized, thoroughly tested frozen stock used as a reference

Q9. Which contamination is hardest to detect and commonly affects established cultures?

• Mycoplasma contamination
• Fungal contamination
• Visible yeast contamination
• Gram-positive bacterial overgrowth

Correct Answer: Mycoplasma contamination

Q10. Which method is standard for authenticating human cell lines?

• Short Tandem Repeat (STR) profiling
• Gram staining
• MTT assay
• Flow cytometry for apoptosis

Correct Answer: Short Tandem Repeat (STR) profiling

Q11. What role does fetal bovine serum (FBS) commonly play in culture media?

• Provides growth factors, hormones, and attachment factors
• Acts as an antibiotic to prevent contamination
• Maintains CO2 concentration in incubator
• Neutralizes trypsin after detachment

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

Q12. Which statement about antibiotics in cell culture is true?

• They can mask contamination and should be used cautiously
• They eliminate the need for aseptic technique
• They increase cell differentiation universally
• They are required for establishing cell banks

Correct Answer: They can mask contamination and should be used cautiously

Q13. Which instrument is used to count cells manually?

• Hemocytometer
• Spectrophotometer
• Centrifuge
• Flow hood

Correct Answer: Hemocytometer

Q14. What is plating efficiency?

• The percentage of seeded cells that form colonies
• The speed at which media is prepared
• Proportion of dead cells after thawing
• The number of contaminants per mL

Correct Answer: The percentage of seeded cells that form colonies

Q15. Which phase of growth is characterized by rapid cell division and high metabolic activity?

• Logarithmic (exponential) phase
• Lag phase
• Stationary phase
• Death phase

Correct Answer: Logarithmic (exponential) phase

Q16. What is contact inhibition?

• Cells stop dividing when they touch neighboring cells
• Bacteria stop growth in presence of antibiotics
• Cells die upon contact with plastic surface
• A method to inhibit viral infection in culture

Correct Answer: Cells stop dividing when they touch neighboring cells

Q17. Which of the following is an anchorage-independent cell growth indicator?

• Soft agar colony formation
• Trypsin sensitivity assay
• Carbon dioxide requirement
• Medium pH measurement

Correct Answer: Soft agar colony formation

Q18. What is the function of a CO2 incubator in cell culture?

• Maintains temperature, humidity, and CO2 to stabilize pH of media
• Sterilizes media using UV light
• Counts viable cells automatically
• Removes mycoplasma from cultures

Correct Answer: Maintains temperature, humidity, and CO2 to stabilize pH of media

Q19. Which buffer system does most culture media use to maintain pH in CO2 incubators?

• Bicarbonate-CO2 buffering system
• Phosphate buffer only
• Tris buffer without CO2
• Acetate buffer system

Correct Answer: Bicarbonate-CO2 buffering system

Q20. What is the recommended thawing practice for cryopreserved cells?

• Thaw rapidly in a 37°C water bath and transfer to warm medium
• Thaw slowly at room temperature overnight
• Directly plate frozen vial without thawing
• Thaw at -20°C to reduce shock

Correct Answer: Thaw rapidly in a 37°C water bath and transfer to warm medium

Q21. Which substance commonly neutralizes trypsin activity after detachment?

• Serum-containing medium
• 0.9% saline
• EDTA only
• Trypsin inhibitor from bacteria

Correct Answer: Serum-containing medium

Q22. What is subculturing (passaging)?

• Transferring cells to fresh vessels to avoid overconfluency and maintain growth
• Freezing cells at low temperature for storage
• Measuring cell viability using dyes
• Contaminating cells on purpose for control

Correct Answer: Transferring cells to fresh vessels to avoid overconfluency and maintain growth

Q23. Why is regular mycoplasma testing important for established cultures?

• Mycoplasma can alter metabolism, gene expression, and experimental outcomes
• Mycoplasma improves cell growth and is beneficial
• It is only necessary for bacterial cultures, not mammalian
• Mycoplasma is visible under light microscope so testing is redundant

Correct Answer: Mycoplasma can alter metabolism, gene expression, and experimental outcomes

Q24. Which dye exclusion method assesses cell membrane integrity?

• Trypan blue exclusion
• MTT color change
• Bromodeoxyuridine incorporation
• PCR amplification of COX genes

Correct Answer: Trypan blue exclusion

Q25. What is cross-contamination of cell lines?

• Unintentional contamination where one cell line overruns another
• Intentional mixing of cells for co-culture
• Contamination of media with bacteria
• Contamination by fungal spores only

Correct Answer: Unintentional contamination where one cell line overruns another

Q26. Which practice minimizes cross-contamination in the lab?

• Using dedicated reagents and properly labeled flasks
• Sharing pipettes between cell lines without cleaning
• Keeping all cell lines in a single open bench
• Using antibiotics to mask contamination

Correct Answer: Using dedicated reagents and properly labeled flasks

Q27. What is a working cell bank (WCB)?

• A freeze stock derived from the master cell bank used for routine production
• The initial primary isolate from tissue
• An untested cell line kept at room temperature
• A bank of contaminated cells for disposal

Correct Answer: A freeze stock derived from the master cell bank used for routine production

Q28. Which of the following is a sign of bacterial contamination in cell culture?

• Medium turns cloudy and pH indicator changes color
• Cells become more adherent and spread evenly
• Cell doubling time decreases predictably
• Cells show increased fluorescence only

Correct Answer: Medium turns cloudy and pH indicator changes color

Q29. Why is Good Laboratory Practice (GLP) important for cell banks?

• Ensures traceability, consistency, and quality of cell stocks
• Only to satisfy aesthetics of lab notebooks
• Because it reduces the need for sterilization
• To allow indefinite use of contaminated stocks

Correct Answer: Ensures traceability, consistency, and quality of cell stocks

Q30. Which method is useful for long-term storage of established cell cultures?

• Storage in liquid nitrogen at -196°C
• Room temperature incubation in sealed flasks
• Refrigeration at 4°C for years
• Dry ice storage without cryoprotectant

Correct Answer: Storage in liquid nitrogen at -196°C

Q31. Which enzymatic supplement is often used with EDTA for detaching cells?

• Trypsin
• Lysozyme
• DNase I
• Collagenase exclusively for all types

Correct Answer: Trypsin

Q32. What does STR profiling detect in cell line authentication?

• Unique short tandem repeat patterns to identify human cell lines
• Antibiotic resistance profiles of bacteria
• Mycoplasma species in culture
• Cell viability percentages

Correct Answer: Unique short tandem repeat patterns to identify human cell lines

Q33. Which component is essential for serum-free defined media to support many cell lines?

• Specific growth factors and attachment factors
• High concentrations of glucose only
• Antifungal agents as the main ingredient
• Undiluted FBS as primary component

Correct Answer: Specific growth factors and attachment factors

Q34. Which procedure can help reduce phenotypic drift in established cultures?

• Limiting passage number and using early-passage stocks from a cell bank
• Continuous culture without banking cells
• Repeated freeze-thaw cycles of working cells
• Increasing serum concentration indefinitely

Correct Answer: Limiting passage number and using early-passage stocks from a cell bank

Q35. What is the typical effect of mycoplasma contamination on cell cultures?

• Altered metabolism, reduced growth, and unreliable experimental data
• Immediate visible turbidity and cell lysis
• Increased cell size visible under low magnification
• Complete immunity to viral infection

Correct Answer: Altered metabolism, reduced growth, and unreliable experimental data

Q36. What is the primary goal of serum starvation in cell culture experiments?

• To synchronize cells at a specific cell cycle phase
• To enrich for bacterial contaminants
• To permanently arrest cells in G0 and induce differentiation irreversibly
• To increase serum concentration gradually

Correct Answer: To synchronize cells at a specific cell cycle phase

Q37. Which detector is commonly used to detect mycoplasma contamination?

• PCR-based assays
• MTT colorimetric test
• Hemocytometer counting
• pH meter readings

Correct Answer: PCR-based assays

Q38. What is anchorage dependence?

• Requirement of cells to attach to a surface for growth
• Ability of cells to grow in suspension without surface attachment
• Dependence on antibiotics for survival
• Dependence on CO2 concentration only

Correct Answer: Requirement of cells to attach to a surface for growth

Q39. Which is a common indicator used in culture media to monitor pH?

• Phenol red
• Bromophenol blue
• Coomassie blue
• Ethidium bromide

Correct Answer: Phenol red

Q40. Which practice ensures safe handling of cell cultures with potential biohazards?

• Following biosafety level guidelines and using biological safety cabinets
• Working on open bench with no PPE
• Using only disposable flasks without sterilization
• Relying solely on antibiotics to control risk

Correct Answer: Following biosafety level guidelines and using biological safety cabinets

Q41. What does viability percentage calculated from trypan blue indicate?

• Proportion of live (unstained) cells among total counted
• Proportion of dead (stained) bacteria only
• Serum protein concentration in medium
• Gas composition inside incubator

Correct Answer: Proportion of live (unstained) cells among total counted

Q42. Why are SOPs important for maintaining established cell cultures?

• They standardize procedures, reduce variability, and ensure reproducibility
• They replace the need for training staff
• They increase contamination by limiting steps
• They are only for documentation and not practical use

Correct Answer: They standardize procedures, reduce variability, and ensure reproducibility

Q43. Which factor best influences cell attachment to culture plastic?

• Surface treatment of the plastic and presence of attachment factors
• Color of the culture flask cap
• Amount of DMSO in the medium
• Ambient light in the lab

Correct Answer: Surface treatment of the plastic and presence of attachment factors

Q44. What is the main advantage of using serum-free media?

• Greater experimental control and reduced variability
• Guaranteed faster growth for all cell types
• No need for sterile technique
• Universal support of primary cells without optimization

Correct Answer: Greater experimental control and reduced variability

Q45. How is cell doubling time most accurately estimated?

• By plotting growth curve and calculating from exponential phase
• By measuring pH changes alone
• By counting cells once at confluency only
• By observing color change in media

Correct Answer: By plotting growth curve and calculating from exponential phase

Q46. Which technique introduces foreign DNA into established cell cultures?

• Transfection
• Cryopreservation
• Trypsinization
• Mycoplasma testing

Correct Answer: Transfection

Q47. What is a feeder layer used for in cell culture?

• To provide supportive factors for growth of more fastidious cells
• To feed bacteria during contamination studies
• To transport cells between labs
• To freeze cells without cryoprotectant

Correct Answer: To provide supportive factors for growth of more fastidious cells

Q48. Which parameter should be recorded in a cell culture logbook regularly?

• Passage number, cell morphology, seeding density, and contamination status
• Only the name of the person who entered the lab
• Ambient room music playlist
• Daily consumption of coffee by staff

Correct Answer: Passage number, cell morphology, seeding density, and contamination status

Q49. Which assay measures cell proliferation by DNA synthesis?

• BrdU (bromodeoxyuridine) incorporation assay
• Trypan blue exclusion
• Gram staining of cultures
• pH titration

Correct Answer: BrdU (bromodeoxyuridine) incorporation assay

Q50. What is the recommended action when a valuable established cell line shows persistent contamination?

• Discard contaminated stocks and retrieve authenticated backup from cell bank
• Ignore contamination and continue experiments
• Increase serum concentration to outcompete contaminants
• Use antibiotics indefinitely to mask contamination

Correct Answer: Discard contaminated stocks and retrieve authenticated backup from cell bank

G S Sachin

I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.

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