micro-organisms and their applications Flashcards
what does aseptic mean
it means not contaminated with microorganisms
how should you sterilise an inoculating loop
pass it through a blue bunsen burner flame
what are inoculating loops used for
inoculating loops are used to transfer microorganisms
what needs to be controlled in an industrial fermenter
temperature pH Nutrient levels Oxygen levels Contamination
how is penicillin extracted from the growth medium in the fermenter
the penicillin is filtered out
what is a fermenter used for
to produce large cultures of microorganisms
give the name and type of microorganism that produces penicillin
Penicillium fungus
why are refrigeration and freezing useful in food storage
food will last longer as microorganisms growth is limited
what does freezing food do to bacterial growth
it stops the growth of microorganisms completely
what does refrigeration of food do to bacterial growth
it slows the growth of microorganisms
what happens to the rate of bacterial growth if the temperature is decreased
the growth rate decreases as the temperature decreases but when the temperature gets too low bacteria will stop growing completely
what happens to the rate of bacterial growth if the temperature is increased
the growth rate increases as the temperature increases but when the temperature gets too high the proteins will denature and the bacteria will die
why is counting colonies an inaccurate method of determine the original number of bacteria
colonies may clump together
often there will be lots of colonies so counting may be difficult
what safety precautions to take when culturing microorganisms
wear protective equipment such as safety glasses
wash hands before and after the practical
clean all work surfaces
keep eyes and face away from culture medium
why should a lid be placed on a agar plate
to prevent microorganisms from the air from contaminating it
to prevent the microorganisms being cultured from contaminating other areas
