environmental control of metabolism 2.6 Flashcards
microbiology
the study of microorganisms
why are microbes good for culturing
their adaptability,
ease of cultivation
speed of growth
what do micro-organisms require
energy source
a source of raw materials
sterile environment
control of abiotic factors
what is a growth media
a solid or liquid used to grow, transport or store microorganisms
complex media
contains one or more crude sources of nutrients and their their chemical composition and components are unkown
defined media
the components are chemically known and are present in relatively pure form
microbial growth requirements
energy source,
vitamins
fatty acids
environmental conditions for microbial growth (abiotic factors)
sterility
temperature
ph
gaseous environment
why are sterile conditions neccessary
reduce competition for nutrients
reduce the risk of spoilage of the product.
what happens in the lag phase
enzymes are induced
exponential phase
rate of grow is at its highest
stationary phase
culture median becomes depleted, secondary metabolites are produced
death phase
lack of respiratory substrate and toxic accumulation of metabolites causes death of cells
primary metabolites
compounds produced by normal cell processes
what causes the death phase
the concentration of primary metabolites increase to toxic levels
