Introduction
Animal cell culture: media, primary and established lines, applications MCQs With Answer is designed for M.Pharm students to strengthen core concepts and practical understanding of mammalian cell culture. This set of focused multiple-choice questions covers essential topics such as types of basal and serum-free media, roles of supplements, isolation and maintenance of primary versus established cell lines, cell handling techniques, contamination issues, cryopreservation, and key applications like vaccine production, monoclonal antibody generation and drug screening. Each question is crafted to reflect practical scenarios and theoretical depth encountered in pharmaceutical research and bioprocessing, helping students prepare for exams and laboratory decision-making with confidence.
Q1. What best defines a primary cell culture?
- Cells isolated directly from animal tissue and maintained for a limited number of passages
- Cells adapted to grow indefinitely due to oncogenic transformation
- Cells grown in suspension in serum-free conditions only
- Cells that have been cloned from a single cell and immortalized
Correct Answer: Cells isolated directly from animal tissue and maintained for a limited number of passages
Q2. Which commonly used basal medium contains a high glucose concentration (approximately 4.5 g/L) and is frequently used for fast-growing adherent mammalian cells?
- RPMI-1640
- DMEM (Dulbecco’s Modified Eagle Medium)
- MEM (Minimum Essential Medium)
- L-15 (Leibovitz’s L-15)
Correct Answer: DMEM (Dulbecco’s Modified Eagle Medium)
Q3. What is the primary functional role of fetal bovine serum (FBS) when added to mammalian cell culture media?
- To provide a sterile environment and kill contaminating microbes
- To supply growth factors, hormones, attachment factors and carrier proteins
- To act solely as a pH indicator in bicarbonate-buffered systems
- To serve as a cryoprotectant during freezing
Correct Answer: To supply growth factors, hormones, attachment factors and carrier proteins
Q4. What is a major advantage of serum-free defined media compared with serum-containing media?
- They always promote faster cell growth than serum-containing media
- They eliminate variability and allow controlled, reproducible experiments
- They require no supplementation with growth factors
- They make cells resistant to viral contamination
Correct Answer: They eliminate variability and allow controlled, reproducible experiments
Q5. Why is trypsin commonly used in adherent cell culture procedures?
- To sterilize the culture surface between passages
- To detach adherent cells from the culture vessel by digesting cell adhesion proteins
- To fix cells for microscopy
- To increase cell membrane permeability for cryopreservation
Correct Answer: To detach adherent cells from the culture vessel by digesting cell adhesion proteins
Q6. Growth of cells in soft agar (anchorage-independent growth) is most indicative of which property?
- High plating efficiency of primary cells
- Cell differentiation into specialized phenotypes
- Cellular transformation and tumorigenic potential
- Strict requirement for serum for adhesion
Correct Answer: Cellular transformation and tumorigenic potential
Q7. HeLa cells, one of the first and most widely used immortal cell lines, were originally derived from which tissue?
- Mouse fibroblasts
- Human cervical carcinoma (uterine cervix)
- Chinese hamster ovary
- Human embryonic kidney
Correct Answer: Human cervical carcinoma (uterine cervix)
Q8. Chinese Hamster Ovary (CHO) cell lines are predominantly used in biopharmaceutical production for which reason?
- They are the only mammalian cells that grow without CO2
- They produce recombinant proteins with appropriate post-translational glycosylation for therapeutic use
- They are resistant to all viral infections
- They require no culture media supplementation
Correct Answer: They produce recombinant proteins with appropriate post-translational glycosylation for therapeutic use
Q9. Which statement correctly describes mycoplasma contamination in cell cultures?
- Mycoplasma are large fungi visible under a light microscope and easy to remove
- Mycoplasma are cell-wall-less bacteria that are difficult to detect by light microscopy and can alter cellular metabolism and experimental results
- Mycoplasma contamination always causes rapid turbidity of the culture medium
- Mycoplasma infections are readily cured by routine cell media changes
Correct Answer: Mycoplasma are cell-wall-less bacteria that are difficult to detect by light microscopy and can alter cellular metabolism and experimental results
Q10. Which cryoprotectant is most commonly used to prevent ice crystal formation during freezing of mammalian cells?
- Glycerol at 90% final concentration
- DMSO (dimethyl sulfoxide) typically at 5–15% final concentration
- Ethanol at 10% final concentration
- Sodium chloride solution at high osmolarity
Correct Answer: DMSO (dimethyl sulfoxide) typically at 5–15% final concentration
Q11. What is the main reason mammalian cell cultures are incubated in a 5% CO2 environment?
- To provide oxygen for aerobic metabolism
- To maintain pH of bicarbonate-buffered media through CO2-bicarbonate equilibrium
- To sterilize the incubator atmosphere
- To increase humidity and prevent evaporation
Correct Answer: To maintain pH of bicarbonate-buffered media through CO2-bicarbonate equilibrium
Q12. The trypan blue exclusion assay measures cell viability by which principle?
- Live cells actively uptake trypan blue and retain the dye
- Only dead cells with compromised membranes permit trypan blue entry and appear stained
- It measures metabolic reduction of a dye to a colored product
- It quantifies DNA content in live cells
Correct Answer: Only dead cells with compromised membranes permit trypan blue entry and appear stained
Q13. Why is it critical to monitor and limit passage number of continuous cell lines in research?
- Higher passage numbers always improve transfection efficiency
- Repeated passaging can lead to genetic drift, phenotypic changes and loss of original characteristics
- Passage number has no effect on experimental reproducibility
- Low passage numbers increase risk of bacterial contamination
Correct Answer: Repeated passaging can lead to genetic drift, phenotypic changes and loss of original characteristics
Q14. The hybridoma technique combines a specific B lymphocyte with a myeloma cell to generate cells used primarily for what purpose?
- Producing long-term primary fibroblast cultures
- Generating monoclonal antibodies with a defined specificity
- Creating immortal epithelial cell lines for toxicology
- Vaccinating animals against viral infections
Correct Answer: Generating monoclonal antibodies with a defined specificity
Q15. Heat-inactivation of serum (56°C for 30 minutes) is performed mainly to:
- Sterilize the serum from bacterial contamination
- Inactivate complement proteins that may damage cultured cells or interfere with assays
- Increase the concentration of growth factors
- Remove lipids and cholesterol
Correct Answer: Inactivate complement proteins that may damage cultured cells or interfere with assays
Q16. What is a major disadvantage of routinely using antibiotics in mammalian cell culture?
- Antibiotics completely prevent mycoplasma contamination
- They can mask poor aseptic technique and allow low-level contamination to persist, and may alter cell physiology
- They always improve cell growth and metabolism
- They increase the accuracy of cell counting
Correct Answer: They can mask poor aseptic technique and allow low-level contamination to persist, and may alter cell physiology
Q17. Which definition best describes cell doubling time?
- The time required for a single cell to complete mitosis
- The time taken for a cell population to increase two-fold during the exponential growth phase
- The interval between media changes
- The duration of the lag phase before growth begins
Correct Answer: The time taken for a cell population to increase two-fold during the exponential growth phase
Q18. Plating efficiency (PE) in clonogenic assays is defined as:
- The number of cells plated per cm2
- The percentage of plated cells that attach and form colonies under defined conditions
- The ratio of live to dead cells immediately after plating
- The absolute number of colonies irrespective of cells plated
Correct Answer: The percentage of plated cells that attach and form colonies under defined conditions
Q19. Short Tandem Repeat (STR) profiling is used in cell culture laboratories primarily to:
- Measure telomere length of cultured cells
- Authenticate human cell lines and detect cross-contamination by DNA fingerprinting
- Quantify mycoplasma contamination levels
- Determine cell cycle phase distribution
Correct Answer: Authenticate human cell lines and detect cross-contamination by DNA fingerprinting
Q20. In viral infection experiments, multiplicity of infection (MOI) refers to:
- The incubation time required for viral adsorption to cells
- The ratio of infectious virus particles to target cells
- The volume of viral inoculum added per mL of culture
- The percentage of cells that survive infection
Correct Answer: The ratio of infectious virus particles to target cells
