Biotechnology — MCQ Practice Questions & Answers

Question 1

Which of the following is the most commonly used culture medium for animal cell culture in laboratories?

Accepted Answer

Correct answer: A. DMEM (Dulbecco's Modified Eagle Medium) — 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.

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B. Luria-Bertani broth

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C. Potato dextrose agar

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D. Czapek Dox medium

Question 2

What is the primary purpose of using a laminar flow hood in cell culture?

Accepted Answer

Correct answer: B. To maintain aseptic conditions and prevent contamination — Laminar flow hoods create unidirectional airflow through HEPA filters, maintaining a sterile environment and preventing microbial contamination during cell culture operations.

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A. To increase the temperature of the culture medium

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C. To enhance cell growth rate by 50%

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D. To reduce the cost of culture media

Question 3

Which of the following characteristics is essential for continuous cell lines?

Accepted Answer

Correct answer: B. Unlimited replicative potential and ability to divide indefinitely — Continuous cell lines (like HeLa, CHO) have unlimited replicative potential due to telomerase activation or genetic modifications, allowing indefinite division unlike primary cultures.

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A. Limited lifespan of 20-30 divisions

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C. Requirement for fresh serum every 6 hours

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D. Complete inability to survive in artificial media

Question 4

What is the normal pH range required for optimal mammalian cell culture?

Accepted Answer

Correct answer: B. 7.2-7.4 — 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.

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A. 4.5-5.5

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C. 8.5-9.0

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D. 6.0-6.5

Question 5

Which hormone is most critical for cell growth and proliferation in serum-containing culture media?

Accepted Answer

Correct answer: C. Growth factors present in serum (FBS) — Fetal Bovine Serum (FBS) contains essential growth factors, hormones, and attachment factors that promote cell growth and proliferation in culture.

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A. Insulin

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B. Thyroxine

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D. Cortisol

Question 6

What is the significance of calculating the cell doubling time in cell culture?

Accepted Answer

Correct answer: B. To assess the growth rate and health status of cells — Cell doubling time indicates the rate at which cells divide and reflects their growth kinetics and overall health. It's calculated from exponential growth phase data.

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A. To determine the exact color of the culture

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C. To reduce the osmotic pressure of the medium

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D. To increase antibiotic concentration

Question 7

Which of the following is NOT a method for cryopreservation of cell cultures?

Accepted Answer

Correct answer: D. Heating cells to 50°C in dry ice — Heating damages cells. Proper cryopreservation uses liquid nitrogen (-196°C) with cryoprotectants like DMSO or glycerol to prevent ice crystal formation that damages cell membranes.

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A. Liquid nitrogen freezing at -196°C

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B. Glycerol-based cryoprotectants

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C. DMSO (Dimethyl sulfoxide) as cryoprotectant

Question 8

What is the Hayflick limit?

Accepted Answer

Correct answer: B. The maximum number of divisions a normal human somatic cell can undergo (approximately 50-70 divisions) — The Hayflick limit describes the maximum replicative potential of normal human cells (~50-70 divisions) due to telomere shortening, after which cells enter senescence.

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A. Maximum temperature a cell culture can tolerate

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C. The minimum pH required for cell survival

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D. The maximum osmotic pressure cells can withstand

Biotechnology - MCQ Practice Questions