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level: Environmental Control of Metabolism

Questions and Answers List

level questions: Environmental Control of Metabolism

QuestionAnswer
what are micro organismsvery small organisms archaea, bacteira and some species of eukaryotes
what do micro organisms use for metabolisma wide variety of substrates and produce a range of products from their metabolic pathways
why are micro organisms used in industrybecause of their adaptability, ease of cultivation and speed of growth
what is biosynthesisthe production of complex molecules within living organisms or cells
what do micro organisms require for biosynthesisraw materials such as amino acids, vitamins and fatty acids
where are the raw materials required for biosynthesis supplied frommany micro organisms produce all the complex molecules required for bio synthesis other micro organisms require these to be supplied in the growth media
what are the two forms of basic growth mediabroth agar
where is an energy source derived from for biosynthesisan energy source is derived either from chemical substrates or from light in photosynthetic micro organisms such as cyanobacteria and algae
what must cells in culture be supplied with in order to growmust be supplied with the correct nutrient medium but also correct culture conditions
how is temperature controlledusing an incubator
how is pH controlledusing buffers or the addition of an acid or an alkali
how is sterility controlledby methods such as heat sterilisation or disinfection
why is controlling oxygen levels in growth medium importantin a gaseous environment some microorganisms are anaerobic and will not grow in the presence of oxygen, others will require good oxygen levels
why is controlling light in growth medium importantif it is a photosynthetic organism
what is the effect of having sterile conditions in fermenterssterile conditions in fermenters reduce competition with desired micro organisms for nutrients and reduce the risk of spoilage of the product
what are the four phases to the growth curvethe lag phase the log/exponential phase the stationary phase the death phase
describe the lag phasewhere enzymes are induced to metabolise substrates
what is the log/exponential phasecontains the most rapid growth of micro organisms due to plentiful nutrients
what is the stationary phaseoccurs due to the nutrients in the culture media becoming depleted and hte production of toxic metabolites secondary metabolites are also produced such as antibiotics. In the wild these metabolites confer an ecological advantage by allowing the micro organisms which produce them to outcompete other micro organisms
describe the death phaseoccurs due to the toxic accumulation of metabolites or the lack of nutrients in the culture
what is a viable cell countinvolves counting only the living micro organisms
what is a total cell countinvolves counting viable and dead cells
what type of cell count can show a death phaseviable cell count only if you took a total cell count, cell number in the culture would remain constant regardless of if cells were dead or not