2 - BACTERIAL GROWTH 2

Question 1

When the growth rate is measured under unrestricted growth conditions what does k=

Answer 1

k = kmax

Question 2

Balanced growth is a limited period but useful for experiments, how do you maintain balanced growth?
(this method is time consuming and manually intensive)

Answer 2

By taking samples from exponential phase at intervals and diluting then in fresh media.
Sample will be taken once every doubling time.
Creates a zigzag pattern where OD fluctuates across a value over time but remains in exponential phase

Question 3

The relationship between substrate concentrations and growth rate is linear except at…

Answer 3

High growth rates, may suggest a difference in the way substrate metabolised at different growth rates

Question 4

Most common method to maintain bacteria in unrestricted growth state?

Answer 4

CHEMOSTAT

Question 5

Components of a chemostat:

Answer 5

MEDIUM RESERVOIR: feeds medium at constant rate
CULTURE VESSEL: contains growth medium
OVERFLOW: allows constant volume to be maintained where removal = addition

Question 6

Chemostat conditions:

Answer 6

• Maintain constant temperature (heater)
• Way to introduce 02 (air inlet)
• Stirring device e.g. magnetic stirrer
• can also be made more complex with devices to measure pH, O2, temp

Question 7

How is growth rate controlled in the chemostat?

Answer 7

By externally adjusting flow of medium containing limiting essential nutrient