Lecture 5 Microbial Growth And Physiology Flashcards
Boiling is what temperature and how long
•100 degrees celcius
•30 minutes
Autoclave is at what temperature and for how long
120 degrees celcius
30 minutes
Dry heat is at what temperature and for how long
•150 degrees celcius
•120 minutes
What process do bacteria divide by
Binary fission
When the chromosome divides during binary fission what does it produce
Two identical copies
Is Bacterial growth described as exponential
Yes the generation time (time for bacterial mass to double) can be as fast as 20 minutes
What temperature does agar melt as
100 degrees celcius
What temperature does agar solidify at
40 degrees celcius
How is Agar sterilised
By Autoclaving
What do bacteria grow as on agar
As Colonies
How many cells/ml for growth in a liquid medium
10^9 cells/ml
For growth in a liquid medium what is position for incubation
Standing or Agitated
What are the growth phases of a Bacterial Culture
•Lag
•Log
•Stationary
•Death
Describe each of the growth phases of a Bacterial Culture
•Lag
Adaption
•Log
Cells multiply at the maximum rate
•Stationary
Lack of nutrients and build up of toxic metabolic intermediates means multiplication is balanced by cell death
•Death
Describe the two direct measurements of Bacterial growth
•Total Cell Count
Using microscope and counting chamber
•Total Viable Count
Cells in culture are diluted and spread on nutrient agar plates