Cell Culture Fundamentals Flashcards

What is the purpose of the CO2 in a cell culture incubator?

Answer: To maintain media pH by equilibrating with bicarbonate-buffered media

CO2 (typically 5%) dissolves in the bicarbonate-buffered media, forming carbonic acid that maintains the media pH at approximately 7.2-7.4.

What does the term 'passage number' refer to in cell culture?

Answer: The number of times cells have been subcultured (split) since the original stock

Passage number tracks how many times a cell line has been subcultured; high passage numbers can result in genetic drift and altered cell behavior.

Which supplement is added to basal cell culture media to provide essential growth factors, hormones, and attachment factors?

Answer: Fetal bovine serum (FBS)

Fetal bovine serum is the most common supplement providing growth factors, hormones, adhesion proteins, and transport proteins that support cell growth and attachment.

What is 'mycoplasma' and why is it a concern in cell culture?

Answer: A small, cell wall-less bacterium that infects cultures invisibly, altering cell behavior

Mycoplasma are tiny bacteria that lack cell walls, pass through 0.22 µm filters, are invisible by light microscopy, and alter cell metabolism, gene expression, and experimental results.

When should you use trypan blue dye when working with cell cultures?

Answer: To assess cell viability by distinguishing live cells (exclude dye) from dead cells (take up dye)

Trypan blue is a vital dye excluded by live cells with intact membranes; dead cells with damaged membranes take up the dye and appear blue, enabling viability counting.

What is the purpose of T-flask size designation (e.g., T-25, T-75, T-175) in cell culture?

Answer: It indicates the total growth surface area in cm² available for cell attachment

The T-designation refers to the total surface area of the flask floor in cm², which determines how many cells the flask can support at confluency.