BACE - Biotechnician Assistant Credentialing Cell Culture Fundamentals Questions and Answers

Question 1

A technician is passaging an adherent mammalian cell line. Which of the following reagents is commonly used to enzymatically detach the cells from the surface of the culture flask?

Accepted Answer

Trypsin-EDTA

Answer

Phosphate-Buffered Saline (PBS)

Answer

Fetal Bovine Serum (FBS)

Answer

Dimethyl sulfoxide (DMSO)

Question 2

A technician observes that a flask of cell culture medium, which was clear and pink the previous day, is now turbid (cloudy) and has turned a distinct yellow color. What is the most likely cause of this change?

Accepted Answer

Bacterial contamination.

Answer

The cells have become over-confluent.

Answer

Fungal contamination.

Answer

The CO2 level in the incubator is too low.

Question 3

What is the primary function of providing a 5% CO2 atmosphere in a standard mammalian cell culture incubator?

Accepted Answer

To work with the bicarbonate buffer system in the medium to maintain a stable pH.

Answer

To provide a direct carbon source for cell metabolism.

Answer

To prevent anaerobic bacteria from growing.

Answer

To increase the dissolved oxygen levels in the culture medium.

Question 4

A biotechnician is preparing to cryopreserve a cell line. What is the primary role of adding dimethyl sulfoxide (DMSO) to the freezing medium?

Accepted Answer

It prevents the formation of large intracellular ice crystals that can damage cell membranes.

Answer

It acts as a primary nutrient source for the cells while frozen.

Answer

It serves as a selective agent to kill any contaminating cells.

Answer

It triggers the cells to enter a state of suspended animation.

Question 5

A technician performs a cell count using a hemocytometer and Trypan Blue exclusion staining. In a specific counted volume, they observe 120 live (unstained) cells and 30 dead (blue-stained) cells. What is the percent viability of the culture?

Accepted Answer

80%

Answer

75%

Answer

25%

Answer

100%

Question 6

When working with cell cultures in a Class II Biological Safety Cabinet (BSC), which of the following is a critical aseptic technique to prevent contamination?

Accepted Answer

Wiping the outside of all media bottles and flasks with 70% ethanol before placing them in the cabinet.

Answer

Wearing two pairs of gloves for extra protection.

Answer

Keeping the UV light on while working to sterilize the air.

Answer

Moving hands and arms rapidly to create a sterile vortex.