D: Batch Culture Flashcards
What is growth
an increase in cell number and/or mass
What is generation time
g, amount of time it takes for a cell number to double
What is balanced growth
all of the cellular components increase proportionately
What is unbalanced growth
all of the cellular components do not increase proportionately
What is batch culture
growth in a broth, can be in test tube or flask, usually a pure culture
What is growth rate
(k or kappa), the number of generations in a set amount of time, often per hour
Descirbe lag phase
there is unbalance growth. as cells adapt to new environment, lots of RNA and protein synthesis
What does length of lag phase depend on
amount of adaptation required
Descirbe log phase/exponential phase
cells replicate exponentially, balanced growth. generation time is constant. length of g affected by environmental conditions like temp, type of media and bacteria genetics
Give an example of g seen in log phase
Mycobacterium tuberculosis g=800 min E. coli g=20 min
Describe stationary phase
growth affected by pop density, number is ~109 cells/ml, and limiting nutrients. eg. nitrogen and carbon source used up. waste accumulates, inhibitng growth
Why is there no change in CFU/ml in stationary phase
some cells growing, some are dying, no net change
Describe starvation response
during stationary phase few genera will produce endospores. most will synthesise proteins that help cell survive
What results in starvation response, what do the cells become resistant to?
result: cell tougher, more resistant to starvation, damage by heat, osmosis pressure, oxidative damage and chemicals
Name some fns of proteins during starvation response
increase on number of crosslinks in peptidoglycan, special proteins bind to DNA to protect it. Also, proteins prevent protein denaturation and help renaturation
