Biotechnology

Contact inhibition is a property where normal mammalian cells stop dividing when they form a monolayer and make physical contact with adjacent cells.

Trypan blue exclusion assay distinguishes viable (unstained) from non-viable (blue) cells. Hemocytometer counts total cells, not viable ones specifically.

FBS provides essential growth factors, hormones, lipids, and attachment factors necessary for cell growth and proliferation in culture.

Basal media contain amino acids, vitamins, inorganic salts, and carbohydrates. Monoclonal antibodies are added supplements, not basal media components.

Mammalian cells require slightly alkaline to neutral pH (7.2-7.4) for optimal growth. pH is maintained using buffers like bicarbonate or HEPES.

Log phase (logarithmic/exponential phase) is when cells divide at maximum rate with doubling time remaining constant. This is the phase of active cell proliferation.

70% ethanol is the standard disinfectant for cell culture work due to its effectiveness against most microorganisms and minimal residual toxicity to cells.

Most mammalian cell lines have doubling times of 12-24 hours under optimal culture conditions. Bacterial doubling times are much shorter (2-4 hours).

Myeloma cell lines (NSO or SP2/0) are immortal cells used to create hybridomas through fusion with B lymphocytes for monoclonal antibody production.

Serum-free media reduce lot-to-lot variability of serum batches, improve product purity, and simplify downstream purification processes, making them essential for pharmaceutical production.