Cell Biology
Measure of adherent cell coverage of a surface
what is percent (%) confluence
What is a buffer?
An aqueous mixture of a weak acid and its conjugate base that resists a change in pH when base or acid is introduced
what are the main process controls on the iCELLis and how are they controlled?
DO, pH, Temperature temperature is controlled by the lauda TCU, DO is controlled by a mass flow controller and plant O2, pH is controlled via the addition of CO2
phase of cell growth immediately after vial thaw
what is lag phase
what is the definition of pH
the p function, or -log (H3O+). Log scale of how acidic or basic something is
what do HEK293 cells consume once glucose and glutamine are depleted
lactate
phase that mammalian cells are passaged in
what is log phase
why does the expiration date change on a pH buffer when it is opened
dissolved CO2 from the atmosphere changes the pH due to its conversion into carbonic acid
what is PEI pro, and what is its function in transfection? Why is the mix timing critical?
Linear polyethylenimine, is a high-charge cationic polymer that readily binds highly anionic substrates (DNA), It packages the DNA so they can pass through the cell membrane. If mixed for too long, complexes become too large and transfection efficiency drops
why is to buffer the bicarbonate components in the media and prevent the media from becoming too basic
what is the definition of osmolality and how is it measured
osmolality is the number of particles in a kg of solution (concentration). it is measured using freezing point depression or osmometry.
how does lysis buffer work
lysis buffer contains denaturing detergents can be anionic such as sodium dodecyl sulfate (SDS) or cationic such as ethyl trimethyl ammonium bromide. These detergents totally disrupt membranes and denature proteins by breaking protein-protein interactions.
cryopreservation agent, and temperature used in long term vial storage
DMSO (dimethyl sulfoxide), <-130 C
what is chromatography?
Chromatography is a chemical or mechanical separation technique using resins as the “stationary phase” and buffers as the “mobile phase”
What is TFF and how does it work
Tangential Flow Filtration
Product is pumped parallel to the filter surface, too large to fit through filter, but does not clog filter (retentate)
Buffer and small impurities move in a tangential direction and pass through the filter (filtrate/permeate), to waste