Key Area 6: Environmental Control Of Metabolism Flashcards
What are three examples of microorganisms?
- bacteria
- algae
- fungi
What are the five properties of microorganisms?
- a vast range of substrates for metabolism
- a diverse range of products are made from metabolic pathways
- adaptability
- easy to cultivate
- quick growth rate
Where can microorganisms derive energy?
Chemical energy (respiration) Light energy (photosynthesis)
What is a simple growth medium?
- specific ingredients
- glucose, amino acids, fatty acids
What is a complex medium?
- non-specific ingredients
- glucose, vitamins, beef extract
What is aseptic technique?
Maintaining sterile conditions which is used when growing bacteria to prevent cross-contamination
What is industrial fermentation?
When vast quantities of microorganisms are grown to produce huge quantities of useful product such as antibiotic
What are conditions that would be monitored in an industrial fermenter?
- temperature
- oxygen concentration
- pH
What happens if oxygen level drops too low in the fermenter?
Computers get messages from sensors and they bring levels back up to normal
What happens if temperature in the fermenter is too high or too low?
Sensors pick it up and tell the computer which corrects it usually by passing more or less water through the cooling jet
What happens to keep pH levels constant?
A buffer is added
What is doubling/generation time?
The time it takes to for a cell to divide
What are the four phases in the bacteria growth graph?
- lag
- log
- stationary
- death
Describe the lag phase
- little to no growth
- enzymes induced and preparing for growth
Describe the log phase
Maximum rate of division
Describe the stationary phase
Secondary metabolites and toxins build up
Limiting factors
Describe the death phase
Toxins are killing microbes
What is exponential growth?
When the cells are doubling in a small amount of time (maximum division rate)
Why is semi-logarithmic graph paper to be used?
To show the enormous number cells in a culture
What are primary metabolites and where are the produced?
Primary metabolites are produced in the lag phase and are useful for growth as energy is used and substrate is broken down
What are secondary metabolites and where are they produced?
Stationary metabolites are produced in the stationary phase and are not useful for growth but give an organism an ecological advantage
Why do secondary metabolites give an ecological advantage?
They prevent competition ?
What three ways can a microorganisms’ metabolism be manipulated?
- precursor
- inducer
- inhibitor
What is a precursor?
Added when there is a continuous supply of a substance needed earlier in an enzyme controlled process to produce lots of end product
What is an inducer?
Added when a continuous supply of a substance is needed to allow a particular enzyme to remain active
What is an inhibitor?
Added when a continuous supply of an inhibitor is needed to prevent the useful metabolite being broken down
