2.6 Environmental Control of Metabolism Flashcards
What do microorganisms do?
Microorganisms use a wide variety of substrates for metabolism and produce a range of products from their metabolic pathways
Why are microorganisms used?
Microorganisms are used due to their adaptability, ease of cultivation and speed of growth
What do microorganisms produce?
Microorganisms produce all the complex molecules required for biosynthesis, for example amino acids, vitamins and fatty acids.
What is an energy source derived from?
An energy source is derived either from chemical substrates or from light in photosynthetic microorganisms
Why are sterile conditions in fermenters required?
Sterile conditions in fermenters reduce competition with desired microorganisms for nutrients and reduce the risk of spoilage of the product
What is the lag phase?
The lag phase is where enzymes are induced to metabolise substrates
What is the log phase?
The log phase contains the most rapid growth of microorganisms due to plentiful nutrients
What is the stationary phase?
The stationary phase occurs due to the nutrients in the culture media becoming depleted and the production of toxic metabolites. Secondary metabolites are also produced such as antibiotics
How do secondary metabolites confer an advantage in the wild?
Secondary metabolites confer an ecological advantage by allowing the microorganisms which produce them to outcompete other microorganisms
What is the death phase?
The death phase occurs due to the toxic accumulation of metabolites or the lack of nutrients in the culture
What is a viable cell count?
Viable cell counts involve counting only the living microorganisms
What is a total cell count?
Total cell counts involve counting viable and dead cells
What do viable cell counts show?
Viable cell counts show a death phase where cell numbers are decreasing
