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OCR Biology F215 > Biotechnology > Flashcards

Flashcards in Biotechnology Deck (22)
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1
Q

Why are microorganisms often used in biotechnology?

A
  • Grow rapidly if conditions are favourable.
  • Can be genetically engineered.
  • Grow well at low temperatures.
  • Grow in any climate.
  • Generate more pure products than chemical processes.
  • Grow on waste nutrient materials.
2
Q

What is biotechnology?

A

It is the industrial use of living organisms to produce:
• Food
• Drugs
• Other products

3
Q

What is happening during the lag phase of a growth curve?

A
  • Adjusting to environment.
  • Cells growing.
  • Protein synthesis.
  • Respiration.
  • The cells are active but not reproducing so population remains fairly constant
4
Q

What is happening during the log phase of a growth curve?

A
  • Microorganisms reproducing

* Population doubles every generation (roughly every 20 mins)

5
Q

What is happening during the stationary phase of a growth curve?

A
• Rate of reproduction = Death Rate (DR)
• Limiting factors - Nutrients 
              - Space 
              - Build up of waste 
• Population size reaches the carrying capacity
6
Q

What is happening during the death phase of a growth curve?

A

• Death rate exceeds the rate of respiration

    - No space 
    - No nutrients 
    - Waste products have reached a toxic level
7
Q

How might population growth be affected if nutrients were added in the lag phase?

A

Unlikely to have an effect as nutrients are not limiting in the lag phase

8
Q

How might population growth be affected if nutrients were added in the stationary phase?

A
  • increase in growth as nutrient supply likely to be limiting
  • but if limiting factors space or waste build up then increasing nutrients unlikely to have an effect
9
Q

How might population growth be affected if waste products were removed in the stationary phase?

A
  • increase in growth as accumulation of waste could be limiting
  • but if limiting factors lack of nutrients or space then removing waste unlikely to have an affect
10
Q

What are primary metabolites?

A
  • substances produced by an organism as part of its normal growth
  • e.g. amino acids, enzymes, proteins, nucleic acids
  • production matches normal growth
11
Q

What are secondary metabolites?

A
  • substances produced that are not part of normal growth
  • e.g. Antibiotics
  • production begins after main growth so does not match population growth
12
Q

What is batch culture?

A
  • where a starter population of microorganisms is supplied with a fixed amount of nutrients in and allowed to grow
  • at the end of the time period the products are extracted
13
Q

What is continuous culture?

A
  • where a culture is set up and nutrients are added and products removed from the culture at intervals
  • the culture is maintained at the exponential phase of the standard growth curve so that it continues to grow and produce its metabolites quickly
14
Q

What are the advantages and disadvantages of batch culture?

A
  • extra nutrients are not added (will eventually run out)
  • waste products are not removed (good for producing secondary metabolites)
  • slower growth because nutrient level declines with time
  • easy to set up and maintain
  • contamination only affects the batch
15
Q

What are the advantages and disadvantages of continuous culture?

A
  • good for production of primary metabolites
  • growth is higher as nutrients are continuously added
  • more costly to maintain
  • contamination is more costly as all product is lost
  • more efficient as only has to be set up once and runs continuously
16
Q

How is pH manipulated in a fermentation vessel in order to maximise the yield?

A

• pH is monitored and kept at the optimum level
–> increases the product yield because enzymes can work efficiently so the rate of reaction is kept as high as possible

17
Q

How is temperature manipulated in a fermentation vessel in order to maximise the yield?

A
  • the temperature is kept at the optimum level by a water jacket that surrounds the vessel
  • this increases the product yield because enzymes can work efficiently to the rate of reaction is kept as high as possible
  • if the temp is too high enzymes would be denatured and if it was too low growth would be slowed
18
Q

How is the volume of oxygen manipulated in a fermentation vessel in order to maximise the yield?

A
  • the volume of oxygen is kept at the optimum level for respiration by pumping in sterile air when needed
  • this increases the the product yield because microorganisms can always respire to provide the energy for growth
  • a lack of oxygen will lead to unwanted products of anaerobic respiration and a reduction in the growth rate
19
Q

How is the type and time of addition nutrient manipulated in a fermentation vessel in order to maximise the yield?

A
  • growth of microorganisms requires a nutrient supply including sources or carbon, nitrogen and other essential vitamins and minerals
  • the timing of nutrient addition can be manipulated depending on whether the process is designed to produce a primary or secondary metabolite
20
Q

What could be the effect of unwanted microorganisms contaminating a batch? (Importance of asepsis)

A
  • may compete with culture microorganisms for nutrients and space
  • reduce the yield of useful products from the culture
  • may cause spoilage to the product
  • may produce toxic chemicals
  • may destroy the culture microorganism and their products
21
Q

What is asepsis?

A

• it is the practice of preventing contamination of cultures by unwanted microorganisms

22
Q

What aseptic techniques can be used to prevent the contamination of a culture?

A
  • washing, disinfecting and steam cleaning all equipment including the fermenter
  • using a fermenter made from polished stainless steel which prevents microbes from sticking to surfaces
  • sterilising all nutrients before they are added to the fermenter which is usually achieved by steam or heat treatment
  • making sure that any air or oxygen bubbled into the fermenter is free from microorganisms which is achieved using very fine filters