2.6 - Environmental control of metabolism Flashcards
microorganisms use a wide variety of ……….. from metabolism and produce a range of products from their ………
substrates, metabolic pathways
why are microorganisms used
their adaptability ease of cultivation and speed of growth
t/f some microorganisms produce all the complex molecules required for biosynthesis and some do not
t
how are complex molecules required for biosynthesis supplied to microorganisms which cannot produce these
through growth media
where is an energy source derived from
chemical substrates or light in photosynthetic microorganisms
name the culture conditions
sterility, control of temperature, oxygen levels and pH
what do sterile conditions in fermenters reduce
competition with desired microorganisms for nutrients and risk of spoilage of the product
name the phases of growth and changes in culture conditions
lag, log/exponential stationary, death
what is the lag phase
enzymes are induced to metabolise substrates
why does the log phase contain the most rapid growth
due to plentiful nutrients
why does the stationary phase occur
the nutrients in the culture media become depleted and toxic metabolites are produced
what are also produced in the stationary phase
secondary metabolites such as antibiotics
in the wild why do metabolites given ecological advantage
they allow the Organism to outcompete others
why does the death phase occur
the toxic accumulation of metabolites or the lack of nutrients in the culture
which type of cell count can show a death phase
viable cell count
