C: Isolation of pure culture Flashcards
What is pure culture
clone of identical cells derived from one cell
What are the methods used to obtain a pure culture
streak plate, spread plate and pour plates
What is streak plating
inoculating loop used to separate bacterial cells on an agar surface. Plates incubated to allow bacteria to grow and form colonies. Goal is to get isolated colonies
Are streak, pour and spread plates quantitative?
Streak no, pour and spread plates quantitative
What are spread plates
set of volume dilution series added to surface of plate. spreader used to spread it over the surface
What are pour plates
set volume of dilution series added to molten agar, mixed and poured into plate
How to make a serial dilution
bacterial sample, a broth, is diluted in a series of 1/100 and or 1/10 dilutions
How do prepare plates to calculate colony forming units/ml
after incubation, plates btwn 30-300 colonies can be counted and used to calculate CFU/ml
How can an inaccurate count of actual number of viable cells in original sample occur
cells stuck together
Why is growth on solid media different in some areas
environment at edge of colony is diff than centre
At the edge of colony what will there be lots of
oxygen and nutirents
At the centre of colony what will there be lots of
waste
