Tutorial 6 - Growth Requirements Flashcards
what are the physical requirements of bacterial growth?
temperature, pH and osmotic pressure
what are the chemical requirements of bacterial growth?
carbon, hydrogen, oxygen, nitrogen, phosphorus and sulphur
what is a heterotroph?
organisms that use an organic source of energy
what is an autotroph?
bacteria that use CO2 as their principle source of carbon
what is a chemoorganotroph?
uses organic chemicals as carbon source
what is a chemolithotroph?
use inorganic chemicals as carbon source
what is a growth factor?
a compound that is required for growth but cannot be synthesised itself
what are some examples of growth factors?
amino acids, vitamins or haemins
what is an extremophile?
organisms that grow in extreme temperatures
what are cardinal temperatures?
the minimum, optimum and maximum temperatures at which the bacteria grow
what is a psychrophile?
found in the poles, optimum temperature of 15 and minimal growth at 0
what is water activity?
measure of the water available
what is a psychotroph?
optimum temperature of 20, cannot grow above 40
what is a mesophile?
optimum temperature of 37-40
what kind of bacteria are mesophiles?
pathogens
what is a thermophile?
optimum temperature of 60, some grow as high as 80
what is a halophile?
thrives in high salt conditions
what is a halotolerant?
can tolerate raised salt levels of around 10%
what is an osomophile?
tolerates high sugar solutions
what does a microbe need if it does not require oxygen?
an electron acceptor for metabolism
what is an obligate aerobe?
need oxygen to grow
what is an obligate anaerobe?
does not need oxygen and can be poisoned by it
what is a facultative anaerobe?
does not require oxygen but grows better if present
what is a microaerophile?
requires a specific level of oxygen
