Quiz: Animal Cell Culture Biotechnology — 16 Fragen

1. Why should a cell culture laboratory include storage at several temperatures, including 4°C, −20°C, −80°C, and liquid-nitrogen temperature?

A. Different biological materials require different storage conditions

B. Cells must be repeatedly cycled through all temperatures

C. Each temperature corresponds to a separate airflow direction

D. Temperature variation is needed to sterilize the work surface

Answer: (A)

Erklärung

Cell culture laboratories store different reagents, samples, and cell stocks under temperature-specific conditions, including refrigeration, freezing, and liquid-nitrogen preservation. Materials are not normally cycled through every temperature.

2. Why can cell and tissue cultures require less test compound than animal models in experimental studies?

A. They convert compounds into stronger active forms

B. They prevent compounds from interacting with cells

C. They eliminate the need to measure compound concentration

D. They use smaller, more controlled biological samples

Answer: (D)

Erklärung

Cell and tissue cultures provide smaller, more homogeneous experimental systems, so less compound is generally needed than in whole-animal models. The other choices do not describe an established advantage of culture systems.

3. A researcher needs a model that closely resembles the original tissue but expects limited cell divisions and increasing fibroblast dominance over time. Which culture type best fits this purpose?

A. Continuous suspension culture

B. Organ culture

C. Chemically defined culture

D. Primary culture

Answer: (D)

Erklärung

Primary cultures resemble their parent tissue but are limited in lifespan, initially heterogeneous, and often become dominated by fibroblasts. Organ cultures preserve three-dimensional organization rather than primarily expanding cells from a tissue sample.

4. A culture has severe, unrecoverable contamination despite attempted treatment. What is the safest course of action?

A. Continue culturing it until the contaminant becomes less visible

B. Increase the antimicrobial concentration without further assessment

C. Mix it with a clean culture to dilute the contamination

D. Discard the culture, decontaminate the workspace, and restart

Answer: (D)

Erklärung

For an unrecoverable contaminated culture, the safest response is disposal followed by workspace decontamination and restarting with a fresh culture.

5. A culture requires a medium whose ingredients and protein additives are all purified and contamination-free. Which type of medium best fits this requirement?

A. Chemically defined medium

B. Conditioned medium

C. Embryo extract medium

D. Natural serum medium

Answer: (A)

Erklärung

A chemically defined medium contains ultrapure inorganic and organic ingredients and may include purified proteins such as growth factors. Conditioned medium contains undefined components released or supplied by cells.

6. Which type of contaminant is generally difficult to detect and includes endotoxins, plasticizers, metal ions, and disinfectant residues?

A. Chemical contaminant

B. Cross-contaminating cell line

C. Fungal contaminant

D. Bacterial contaminant

Answer: (A)

Erklärung

Chemical contaminants are usually difficult to detect and include endotoxins, plasticizers, metal ions, and traces of disinfectants. Biological contaminants more often produce visible effects.

7. A culture contains cells from a different established cell line, but no microorganism has been introduced. What is this problem called?

A. Endotoxin contamination

B. Chemical contamination

C. Biological contamination

D. Cross-contamination

Answer: (D)

Erklärung

Cross-contamination specifically means that cells from another cell line have entered the culture. Contamination more broadly can involve unwanted microorganisms or substances.

8. A researcher uses bicarbonate buffering in a culture medium. Which atmospheric condition is needed to maintain this buffering system?

A. An atmosphere containing 5–10% carbon dioxide

B. An atmosphere without controlled gases

C. An atmosphere containing 1–2% oxygen

D. An atmosphere containing 20–25% nitrogen

Answer: (A)

Erklärung

Natural buffering depends on equilibrium between gaseous carbon dioxide and carbonate/bicarbonate in the medium, requiring an atmosphere containing 5–10% CO₂. HEPES buffering does not require controlled gaseous CO₂.

9. What is the recommended first step after contamination is detected in a cell culture?

A. Increase the serum concentration in the medium

B. Add a broad-spectrum antibiotic immediately

C. Identify the type of contaminant present

D. Transfer the culture to a larger incubator

Answer: (C)

Erklärung

The contaminant should first be identified as bacterial, fungal, mycoplasmal, or yeast contamination. This identification guides isolation and subsequent decontamination decisions.

10. Which research applications commonly use animal tissue culture to investigate biological responses under controlled conditions?

A. Ecology, astronomy, geology, and meteorology

B. Nutrition, climatology, seismology, and oceanography

C. Developmental biology, pharmacology, toxicology, and regenerative medicine

D. Taxonomy, paleontology, linguistics, and archaeology

Answer: (C)

Erklärung

Animal tissue culture is used in developmental biology, pharmacology, toxicology, and regenerative medicine. These fields benefit from studying cells or tissues under controlled experimental conditions.

11. What is the distinct effect of the high-molecular-weight fraction of chick embryo extract in cell culture?

A. It promotes general cell survival without differentiation

B. It supplies iron for cellular metabolism

C. It prevents attachment of cells to the culture surface

D. It promotes pigment-cell and cartilage-cell differentiation

Answer: (D)

Erklärung

The high-molecular-weight fraction promotes differentiation of pigment cells and cartilage cells. The low-molecular-weight fraction instead promotes cell proliferation.

12. Which measurement describes the ability of individual cells to produce colonies?

A. Cloning efficiency

B. Plateau-phase growth

C. Plating efficiency

D. Population doubling time

Answer: (A)

Erklärung

Cloning efficiency measures whether individual cells can generate colonies, whereas plating efficiency measures the proportion of seeded cells that attach and grow into colonies.

13. Why are organ and embryo cultures generally less suitable than cell cultures for large-scale production?

A. They consist exclusively of isolated cells in suspension

B. They lack differentiated cells and physiological functions

C. They grow slowly and require fresh explantation for each experiment

D. They cannot be maintained in a three-dimensional form

Answer: (C)

Erklärung

Organ and embryo cultures maintain differentiated cells and physiological functions, but their slow growth and need for fresh explants make scale-up difficult. These features distinguish them from more scalable cell culture systems.

14. Which combination of environmental conditions is essential for maintaining mammalian cells in a culture incubator?

A. Strong ultraviolet radiation, dry air, and uncontrolled CO₂

B. Freezing temperature, low pressure, and continuous airflow

C. Low humidity, variable temperature, and atmospheric nitrogen

D. Controlled temperature, high humidity, and regulated CO₂ tension

Answer: (D)

Erklärung

A cell culture incubator must provide controlled temperature, high humidity, and controlled CO₂ tension. These conditions help maintain cell viability and the appropriate chemical environment of the medium.

15. Which component of serum binds iron, reducing its toxicity while increasing its bioavailability to cultured cells?

A. Fibronectin

B. Fetuin

C. α₂-macroglobulin

D. Transferrin

Answer: (D)

Erklärung

Transferrin binds iron and makes it less toxic and more bioavailable. Fibronectin and fetuin primarily enhance cell attachment, while α₂-macroglobulin inhibits trypsin.

16. Why should antibiotics and antimycotics be evaluated using dose-response testing before routine use in contaminated cultures?

A. High concentrations may be toxic to certain cell lines

B. Low concentrations permanently alter the culture medium

C. These agents remove chemical contaminants more effectively at high doses

D. Dose-response testing prevents all future contamination

Answer: (A)

Erklärung

Antibiotics and antimycotics can harm some cell lines at high concentrations, so their effects should be tested across doses before use.