Biotechnology is one of the few subjects where exam questions track laboratory practice closely, so the techniques are worth knowing in order. Practice covers recombinant DNA technology, PCR and gel electrophoresis, cloning vectors, tissue culture, fermentation and bioprocess technology, and applications in medicine and agriculture. Technique questions explain why a step exists, not just what it produces.
Which of the following is the most commonly used culture medium for animal cell culture in laboratories?
Answer: A
DMEM is the most widely used culture medium for mammalian/animal cell culture due to its balanced nutrient composition. LB broth is for bacteria, PDA for fungi, and Czapek Dox for fungi.
Q.2Easy
What is the primary purpose of using a laminar flow hood in cell culture?
Answer: B
Laminar flow hoods create unidirectional airflow through HEPA filters, maintaining a sterile environment and preventing microbial contamination during cell culture operations.
Q.3Easy
Which of the following characteristics is essential for continuous cell lines?
Answer: B
Continuous cell lines (like HeLa, CHO) have unlimited replicative potential due to telomerase activation or genetic modifications, allowing indefinite division unlike primary cultures.
Q.4Easy
What is the normal pH range required for optimal mammalian cell culture?
Answer: B
Mammalian cells require a pH of 7.2-7.4 (physiological pH) for optimal growth. This is maintained using buffers like bicarbonate or HEPES in culture media.
Q.5Easy
Which growth factor is primarily responsible for promoting cell proliferation in mammalian cell culture media?
Answer: A
EGF is a primary mitogenic growth factor that stimulates cell proliferation. While other factors support cell survival, EGF is specifically responsible for promoting cell division in mammalian cultures.
Q.6Easy
What is the primary purpose of using serum-free media (SFM) in industrial cell culture?
Answer: B
Serum-free media reduce lot-to-lot variability of serum batches, improve product purity, and simplify downstream purification processes, making them essential for pharmaceutical production.
Q.7Easy
Which of the following cell lines is commonly used for monoclonal antibody production?
Answer: B
Myeloma cell lines (NSO or SP02) are immortal cells used to create hybridomas through fusion with B lymphocytes for monoclonal antibody production.
Q.8Easy
The doubling time of mammalian cells cultured in vitro typically ranges between:
Answer: B
Most mammalian cell lines have doubling times of 12-24 hours under optimal culture conditions. Bacterial doubling times are much shorter (2-4 hours).
Q.9Easy
Which disinfectant is most commonly used for sterilizing bioreactor surfaces and cell culture equipment?
Answer: A
70% ethanol is the standard disinfectant for cell culture work due to its effectiveness against most microorganisms and minimal residual toxicity to cells.
Q.10Easy
Which growth phase of bacterial culture is characterized by maximum specific growth rate and exponential increase in cell number?
Answer: B
Log phase (logarithmic/exponential phase) is when cells divide at maximum rate with doubling time remaining constant. This is the phase of active cell proliferation.
Q.11Easy
What is the optimal pH range for mammalian cell culture?
Answer: B
Mammalian cells require slightly alkaline to neutral pH (7.2-7.4) for optimal growth. pH is maintained using buffers like bicarbonate or HEPES.
Q.12Easy
Which of the following is NOT a component of basal culture media?
Answer: C
Basal media contain amino acids, vitamins, inorganic salts, and carbohydrates. Monoclonal antibodies are added supplements, not basal media components.
Q.13Easy
In animal cell culture, what is the primary purpose of using serum (typically fetal bovine serum)?
Answer: B
FBS provides essential growth factors, hormones, lipids, and attachment factors necessary for cell growth and proliferation in culture.
Q.14Easy
Which method is most appropriate for counting viable cells in a culture?
Answer: B
Trypan blue exclusion assay distinguishes viable (unstained) from non-viable (blue) cells. Hemocytometer counts total cells, not viable ones specifically.
Q.15Easy
What is contact inhibition in mammalian cell culture?
Answer: A
Contact inhibition is a property where normal mammalian cells stop dividing when they form a monolayer and make physical contact with adjacent cells.
