Biotechnology Flashcards
(34 cards)
What is batch fermentation?
-Closed-system process
-Add a fixed amount of nutrients and microorganisms to a fermentation and allow it to ferment with no additional input. -Once complete, harvest the batch and process the products.
What is continuous fermentation?
- Open-system process
- Fresh nutrients are continuously added
- Allows microorganisms to stay in the exponential phase
- Continuous production of desired product
What are the strengths of batch fermentation?
- Easier to set up
- Don’t need to maintain growing conditions
- Only 1 batch lost if contaminated
- Production of secondary metabolites
What are the limitations of batch fermentation?
- Slower as nutrients runs out
- Production of primary stops
What are the stages of bacterial growth?
- Lag phase
- Log phase
- Stationary phase
- Death phase
What occurs in the lag phase?
- Cells acclimatising
- Genes activating
- No reproduction
What occurs in the log phase?
Population doubled each generation (generation time dependant on conditions)
What happens in the stationary phase?
- Reproduction of new individuals is equal to death rate
- Materials used up and waste starts to build up
What happens in death phase?
- Nutrients used up
- Waste reaches toxic level
- Death > reproduction
- Individuals will die if closed system
What is a primary metabolite?
- Formed during growth phase
- Level of metabolite = level of population
- Materials produced from normal growth, e.g. amino acids
What is a secondary metabolite?
- Formed near end of growth phase
- Levels don’t match population
- Need careful manipulation of growth conditions to ensure production
What type of fermentation would be most suitable for producing penicillin? Why?
Batch as nutrients isn’t maintained (stress enabled) so secondary metabolites produced to survive.
What is the definition of a clone?
Genetically identical to the original.
What are naturally occurring clones?
- Mz twins
- Asexual reproduction in plants, and bacteria by binary fission
What are root suckers?
When the main plant is damaged, they produce these from meristem tissue in trunk where least damage occurs. This becomes the main if the main plant dies.
What are tubers?
Food stores stay dormant over winter and sprout new stems in spring.
What are bulbs?
Plants grow from bulb and produce seeds. New bulbs form at base of the original.
What are runners?
Shoots grown out from parent plant.
What are advantages of vegetative reproduction?
- Quick
- Less variation (guaranteed outcome)
- Only 1 parent needed
- Don’t rely on pollinators/ seed distributors
What are the disadvantages of vegetative reproduction?
- Less variation
- Less opportunity to adapt if conditions change
- No seeds produced so less dispersal
How are cuttings done?
- Cut between nodes
- (use hormones to encourage root development)
- Cut end of stem placed in damp soil
- Roots develop and new plant is produced (clone)
How are grafts done?
- Shoot section removed from tree
- Already growing root and stem (rootstock) has a wedge-shaped hole cut
- Stem (graft) inserted into hole
- Graft is clone of the plant it was cut off but rootstock is not
- (select healthier and control height with rootstock)
What is micro propagation?
- Tissue culture technique
- Used to rapidly produce large batch of clone plants from small sample.
What are the advantages of micro propagation?
- Grow plants which can’t be easily grown via other methods
- Grow a vast amount (to increase population)
