Introduction to cell culture techniques MCQs With Answer

Introduction to cell culture techniques MCQs With Answer

This question set is designed especially for M.Pharm students preparing for the Modern Bio-Analytical Techniques (MPA 202T) course. The 20 multiple-choice questions cover foundational and advanced aspects of mammalian cell culture, including aseptic practices, media composition, cell line types, contamination control, cryopreservation, cell counting and viability assays, incubator conditions, and authentication methods. Each question forces application-level thinking relevant to laboratory practice and exam scenarios. Use these MCQs to test conceptual understanding, refine practical decision-making, and identify areas for focused study in preparation for university exams and practical assessments.

Q1. Which component in basal cell culture media primarily maintains osmotic balance and provides essential ions for cell function?

• Sodium chloride and bicarbonate
• Glucose
• Amino acids
• Vitamins

Correct Answer: Sodium chloride and bicarbonate

Q2. What is the principal reason for heat-inactivating fetal bovine serum (FBS) before use in some cell culture protocols?

• To denature growth factors that stimulate overproliferation
• To inactivate complement proteins that can lyse certain cell types
• To sterilize the serum by killing all bacteria and fungi
• To remove lipids that interfere with cell attachment

Correct Answer: To inactivate complement proteins that can lyse certain cell types

Q3. Which of the following best distinguishes a primary cell culture from a continuous (immortalized) cell line?

• Primary cultures are derived from tumors; continuous lines originate from normal tissues
• Primary cultures have finite replicative capacity and donor-specific traits; continuous lines can proliferate indefinitely
• Primary cultures are always easier to transfect than continuous lines
• Primary cultures do not require serum supplementation while continuous lines do

Correct Answer: Primary cultures have finite replicative capacity and donor-specific traits; continuous lines can proliferate indefinitely

Q4. Which method is most appropriate for detecting mycoplasma contamination in a mammalian cell culture lab?

• Regular Gram staining of culture supernatants
• Polymerase chain reaction (PCR) targeting mycoplasma sequences
• Measuring pH change in the medium only
• Observation of turbidity in the culture flask

Correct Answer: Polymerase chain reaction (PCR) targeting mycoplasma sequences

Q5. When trypsinizing adherent cells, what is the primary purpose of adding EDTA along with trypsin in many protocols?

• EDTA acts as a buffer to maintain pH during detachment
• EDTA chelates divalent cations to disrupt cell–cell and cell–substrate adhesions, enhancing trypsin efficiency
• EDTA acts as an antimicrobial to prevent contamination
• EDTA provides nutrients to cells during detachment

Correct Answer: EDTA chelates divalent cations to disrupt cell–cell and cell–substrate adhesions, enhancing trypsin efficiency

Q6. Which gas composition is typically maintained in a mammalian CO2 incubator for most cell lines to keep pH regulated via bicarbonate buffering?

• 21% O2, 0.04% CO2
• 5% CO2, balance air (≈21% O2)
• 100% nitrogen
• 10% CO2, 50% O2

Correct Answer: 5% CO2, balance air (≈21% O2)

Q7. Which cryoprotectant is most commonly used at ~10% final concentration to prevent ice crystal formation during slow-rate freezing of mammalian cells?

• Glycerol
• Sucrose
• Dimethyl sulfoxide (DMSO)
• Ethylene glycol

Correct Answer: Dimethyl sulfoxide (DMSO)

Q8. In cell culture sterility testing, what does the LAL (Limulus Amebocyte Lysate) assay detect and why is it relevant?

• Endotoxin (lipopolysaccharide) contamination from Gram-negative bacteria which can affect cell responses
• Viral contamination by detecting viral proteins
• Fungal spores by measuring chitin fragments
• Mycoplasma DNA by colorimetric change

Correct Answer: Endotoxin (lipopolysaccharide) contamination from Gram-negative bacteria which can affect cell responses

Q9. Which technique is most appropriate for routine viable cell counting and distinguishing live from dead cells in suspension cultures?

• Hemocytometer counting with trypan blue exclusion
• Measuring optical density at 600 nm
• Gram staining and microscopy
• ELISA for albumin content

Correct Answer: Hemocytometer counting with trypan blue exclusion

Q10. What is the main advantage of using serum-free or chemically defined media for certain cell culture applications?

• They always increase cell proliferation rates compared to serum-containing media
• They reduce variability and eliminate undefined serum components that can confound experiments
• They eliminate the need for sterile technique
• They are universally compatible with all cell types without optimization

Correct Answer: They reduce variability and eliminate undefined serum components that can confound experiments

Q11. Which of the following is the best practice to minimize cross-contamination between different cell lines in a shared tissue culture facility?

• Label flasks only when an experiment is complete
• Use separate dedicated incubator shelves and work with one cell line at a time within a biosafety cabinet
• Store all cell lines in the same cryovial rack to save space
• Never authenticate cell lines after thawing

Correct Answer: Use separate dedicated incubator shelves and work with one cell line at a time within a biosafety cabinet

Q12. Which method is considered the gold standard for cell line authentication to detect cross-contamination or misidentification?

• Mycoplasma PCR
• Short Tandem Repeat (STR) profiling
• Trypan blue exclusion test
• Observation of morphology only

Correct Answer: Short Tandem Repeat (STR) profiling

Q13. In adherent cell cultures, which surface treatment enhances cell attachment by increasing hydrophilicity and providing charged groups on tissue culture plastic?

• Non-treated polystyrene
• Plasma or corona treatment (tissue culture-treated plastic)
• Sterilization with 70% ethanol alone
• Coating with paraffin wax

Correct Answer: Plasma or corona treatment (tissue culture-treated plastic)

Q14. Which type of contamination often goes undetected because organisms are very small, lack cell walls, and do not cause turbidity but can alter cell physiology?

• Fungal contamination
• Mycoplasma contamination
• Gram-positive bacterial contamination
• Viral contamination always visible by turbidity

Correct Answer: Mycoplasma contamination

Q15. For scaling up suspension mammalian cell cultures in a bioreactor, which parameter is most critical to control to prevent shear stress–induced damage?

• Incubator room temperature only
• Agitation speed and impeller design to maintain appropriate shear conditions and oxygen transfer
• Concentration of antibiotics in the medium
• Frequency of manual flask handling

Correct Answer: Agitation speed and impeller design to maintain appropriate shear conditions and oxygen transfer

Q16. Which assay is commonly used to measure metabolic activity as a proxy for cell viability in high-throughput culture experiments?

• MTT or resazurin (alamarBlue) colorimetric/fluorometric assays
• Gram staining
• Hemocytometer without dyes
• LAL assay for endotoxin

Correct Answer: MTT or resazurin (alamarBlue) colorimetric/fluorometric assays

Q17. Why should antibiotics not be used routinely as a substitute for aseptic technique in cell culture?

• Antibiotics completely prevent all types of contamination and are therefore safe to rely on
• Antibiotics can mask low-level contamination, promote resistant strains, and alter cell physiology
• Antibiotics increase cell proliferation rate and thus change experimental results
• Antibiotics are expensive but otherwise harmless to experiments

Correct Answer: Antibiotics can mask low-level contamination, promote resistant strains, and alter cell physiology

Q18. When calculating population doubling time, which two measurements are required over a defined culture interval?

• Initial cell number and final cell number
• Final medium volume and initial pH
• Cell morphology and confluence percentage only
• Antibiotic concentration and incubation temperature

Correct Answer: Initial cell number and final cell number

Q19. What is the function of extracellular matrix coatings such as fibronectin or collagen when applied to culture surfaces?

• To provide mechanical stiffness only without affecting cell signaling
• To supply adhesive ligands and biochemical cues that promote attachment, spreading, and specific cell behavior
• To sterilize the plastic surface
• To act as an energy source for cells

Correct Answer: To supply adhesive ligands and biochemical cues that promote attachment, spreading, and specific cell behavior

Q20. During controlled-rate freezing of cells, why is a cooling rate of approximately -1°C per minute commonly used before transfer to liquid nitrogen?

• To ensure complete dehydration of cells prior to storage
• To balance intracellular ice formation and osmotic dehydration, minimizing lethal ice crystals
• To denature proteins for easier recovery
• To allow antibiotics to penetrate cells

Correct Answer: To balance intracellular ice formation and osmotic dehydration, minimizing lethal ice crystals

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