Cell Culture Fundamentals Flashcards
6 cards from real BACE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Cell Culture Fundamentals flashcards as text
What is the correct method for cryopreservation of mammalian cells?
Answer: Freeze cells slowly (1°C/min) in a cryoprotectant like DMSO then transfer to liquid nitrogen (-196°C)
Controlled-rate freezing (1°C/min) in cryoprotectant (typically 10% DMSO) prevents lethal intracellular ice crystal formation; long-term storage at -196°C in liquid nitrogen halts all cellular processes.
What does 'serum-free' media formulation offer compared to serum-supplemented media in bioprocessing?
Answer: Defined reproducible composition without animal-derived components supporting regulatory compliance
Serum-free media has a defined, consistent chemical composition, eliminates batch-to-batch serum variability, reduces contamination risks, and meets regulatory requirements for biopharmaceutical production.
What is 'cell senescence' in the context of primary cell culture?
Answer: The irreversible arrest of cell division after a finite number of passages (the Hayflick limit)
Senescence is the irreversible loss of proliferative capacity in primary cells after approximately 50-70 population doublings, as described by the Hayflick limit.
When splitting (passaging) adherent cells, trypsin is added after washing with PBS. What is the purpose of the PBS wash?
Answer: To remove serum proteins that would inhibit trypsin activity
FBS/serum in the culture media contains trypsin inhibitors (alpha-2-macroglobulin and alpha-1-antitrypsin); washing with PBS removes these inhibitors before adding trypsin.
What is the significance of a cell culture 'split ratio' of 1:3?
Answer: Cells from one flask are divided into three new flasks diluting density by one-third
A 1:3 split ratio means cells harvested from one flask are divided equally into three new flasks, reducing the cell density to one-third and allowing room for cells to grow until the next passage.
Which characteristic distinguishes a 'transformed' cell line from a 'primary' cell line?
Answer: Transformed cell lines have acquired the ability to grow indefinitely (immortality) due to genetic alteration
Cell transformation confers immortality — indefinite proliferative capacity — unlike primary cells that senesce after finite passages.