What is the scientific term used to describe the growth of bacteria under laboratory conditions?
Multiplying
Culturing
Optimal conditions
Micro-organisms are what?
Archaea, bacteria
Some species of eukaryotes
Both of the above
Which condition must be controlled in order to stop contamination of a growth medium?
pH
Nutrients
Sterility
Under optimal conditions, the bacteria E. Coli multiplies every 20 minutes. How many bacterial cells will there be if one E. Coli cell was cultured under optimal conditions for 1 hour and 40 minutes?
16
64
32
Which description is the most appropriate to the lag phase during a microorganism growth pattern?
Microorganisms adjust to the conditions of the growth media and enzymes are induced to metabolise substrates
Microorganisms multiply at a constant rate
Nutrients in the growth medium are exhausted and metabolites build up
The nutrients in the growth medium are depleted and the number of microorganisms stays the same so there is no overall growth. Which phase does this describe?
Exponential phase
Stationary phase
Death phase
Why does the growth of microorganisms result in a death phase?
All substrates are depleted and there is a build-up of toxic metabolites so the microorganisms die
All microorganisms have a limited number of times they can multiply and so they all die eventually
Their metabolic pathways change and they can no longer use the original substrate
Which stage shows the exponential growth phase?
Z
Y
X
Primary and secondary metabolites are associated with which phases of microorganism growth?
Primary – exponential phase / Secondary – stationary phase
Primary – exponential phase / Secondary – death phase
Primary – Lag phase / Secondary – Stationary phase
Secondary metabolites can give microorganisms what kind of advantage?
Behavioural
Ecological
Structural