Metabolism And Survival (Key Area 6) Flashcards
Micro organisms are __________, __________ and some species of __________.
Archaea, bacteria and some species of eukaryotes.
Do micro organisms use a wide or limited variety of substrates for metabolism.
Wide variety
Do micro organisms produce a limited number or a wide variety of products from their metabolic pathways?
Wide variety
Micro organisms are used in industry because…
Of their adaptability, ease of cultivation and speed of growth.
Many micro organisms produce all the complex molecules required for __________, for example __________, __________ and __________.
Biosynthesis, for example amino acids, vitamins and fatty acids.
Some micro organisms require __________, __________ and __________ to be supplied in the growth media.
Vitamins, amino acids and fatty acids.
When culturing micro organisms, their growth media require raw materials for __________ as well as an __________ __________.
Biosynthesis/ energy source
An energy source is derived from either a __________ substrate or from __________ in photosynthtic micro organisms.
Chemical/ light
Conditions required when culturing micro organisms:
Sterililty, control of temperature, oxygen levels and pH.
What do sterile conditions in fermenters reduce?
Competition with dersired micro organisms and other micro organisms for nutrients. Also reduces the risk of spoilage of the product.
What are the phases of growth for microorganisms?
Lag, log/ exponential, stationary and death.
Describe what happens during the lag phase.
Enzymes are induced to metabolise substrates.
Describe what happens during the log/ exponential phase.
The most rapid growth of micro organisms occurs due to plentiful nutrients.
Describe what happens during the stationary phase.
Nutrients in the culture media are depleting and toxic metabolites are being produced. Secondary metabolites (such as antibiotics) are also produced, in the wild these metabolites confer as ecological advantages by allowing the microorganisms which produce them to out compete with others.
Describe what happens during the death phase.
This occurs due to the toxic accumulation of metabolites or due to the lack of nutrients in the culture.
