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Measuring Growth Lecture Test 2
What are direct methods of measuring growth
Indirect methods of measuring bacterial growth?
Trubidity with the use of a spectrophotometer
or enzymatic activities
Other ways of measuring bacterial growth?
What technique can you use to get a pure culture of bacteria?
Isolation techniques, streak a plate for isolation.
What does a selective media do?
Selects for one type of bacteria over another.
What does a differential media do?
It will differentiate differences in bacteria such as formation of lactose.
How is a MSA (Manatol Salt Agar) plate selective and differential?
Selective for bacteria that can grow in high salt.
Differential for mannitol fermenters,
Mannitol fermenters will ferment and release acid that changes the pH indicator in the media from pink to yellow
Non mannitol fermenters will not change the color of the media.
How many cells are needed to form a colony on a plate?
What is generation time?
Is the time needed for one cell to divide and become two cells.
Calculation of final concentration?
Final [ ] = (initial concentration)(2 to the power of # of generation)
: Final [ ] = (1.0 x 10^2)(2^5)
Final [ ] = 3200 cells
Calculation of generation time?
Generation Time = Time (in min.) / number of generations
Example: GT = 120min / 10.3 gnenerations
GT= 11.7 min/generation