OCR Biology A - 6.2.1 - Cloning and Biotech Part 2
This deck Continuous culture has a higher risk of contamination, which can stop production entirely.
Disadvantages of continuous culture
Contamination is more likely
Difficult to maintain and control product consistency
In cases of contamination losses are great and all production halts
Key Terms
Disadvantages of continuous culture
Contamination is more likely
Difficult to maintain and control product consistency
In cases of contamination losses are great and all p...
Advantages of batch culture
Less likelihood of contamination
Can be left for a set time period
Useful for secondary metabolites
In the event of contamination...
Disadvantage of batch culture
Fermenter isn't in use constantly - less efficient
| Time spent cleaning
Primary metabolites
Produced in the course of normal metabolism e.g. proteins, enzymes, alcohol
Produced in lag and log phase
Secondary metabolites
Produced after main population growth has occurred, nutrients are in short supply and population isn't growing rapidly
Produced in stationary...
How do fermenters maximise the yield
Tube for sterile air to provide oxygen for aerobic reactions
Sparger - diffuses air through culture medium
Powerful motors - mixes cont...
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| Term | Definition |
|---|---|
Disadvantages of continuous culture | Contamination is more likely Difficult to maintain and control product consistency In cases of contamination losses are great and all production halts |
Advantages of batch culture | Less likelihood of contamination Can be left for a set time period Useful for secondary metabolites In the event of contamination, only one batch is lost |
Disadvantage of batch culture | Fermenter isn't in use constantly - less efficient | Time spent cleaning |
Primary metabolites | Produced in the course of normal metabolism e.g. proteins, enzymes, alcohol Produced in lag and log phase |
Secondary metabolites | Produced after main population growth has occurred, nutrients are in short supply and population isn't growing rapidly Produced in stationary and death phase |
How do fermenters maximise the yield | Tube for sterile air to provide oxygen for aerobic reactions Sparger - diffuses air through culture medium Powerful motors - mixes contents ensuring equal distribution of nutrients and so microbes don't settle at base of fermenter Acid-base injection site - controls pH Culture broth - contains sources of carbon and nitrogen (NH3) and vitamins/minerals Jacket - filled with hot/cold water to provide optimum temp as respiration releases heat (denaturing) |
Asepsis in fermenters | Washing. disinfecting and steam cleaning all equipment Using fermenter made of polished stainless steel so microbes cant stick Sterilising all nutrients w/ steam or heat Only bubbling in sterile air- v. fine filters |
Phases in microorganim growth curves (bacteria/fungi) | Lag Exponential Stationary Death |
Lag phase | Reproduction v. slow as cells acclimitase, absorb nutrients Gene expresion for spp enzymes Synthesis of enzymes and organelles |
Exponential phase | Reproduction is rapid No limiting conditions Few cells die |
Stationary phase | Population remains constant as death and reproduction rates are the same |
Death phase | Lack of resources | Build up of CO2 - fatal |
Culture | A method of multiplying microbial organisms by letting them reproduce in predetermined culture medium under controlled lab conditions |
Isolated enzymes | Taking enzymes out of microorganism |
Issue w/ isolated enzymes | Product must be seperated from enzymes and extraction is v. expensive |
Immobilised enzyme | Enzymes fixed to a surface and do not freely mix w/ the substrate |
Ways to immobilise enzymes | Covalent bonding Encapsulation Adsorption Entrapment |
Covalent bonding to immobilise enzymes | Covalently bonded to a supporting surface | Enzymes are also covalently bonded together using a cross-linking agent |
Adsorption | Bound to supporting surface by a combination of hydrophobic interactions and ionic links Bound w/ active site exposed and accessible to substrate |
Entrapment | Trapped in a matrix (often calcium alginate beads) that doesn’t allow free movement |
Encapsulation/membane separation | Separated from reaction mixture by a small permeable membrane - microcapsule |
A vs D of adsorption | Simple and cheap Can be used in a variety of processes Enzymes v. accessible May distort active site Enzymes can detach and leak into reaction mixture |
A vs D of covalent bonding | Enzyme less likely to become detached pH and substrate conc have little effet on enzyme activty Accessible to substrate Expensive Can distort active site, reducing activity |
A vs D of encapsulation | Relatively simple Relatively small effect on enzyme activity Widely apllicable to diff processes Expensive Substrate and product has to be small in order to diffuse through partially permeabe membrane Diffusion is slow |
A vs D of entrapment | Widely applicable to diff processes May be expensive Difficult to entrap Effect of entrapment on enzyme activity dpends on the matrix Substrate and product needs to be small |
Examples of immobilised enzymes | Glucose isomerase Penicillin acylase Lactase Aminoacylase Glucoamylase Nitrile hydratase |
Penicillin acylase | Converts naturally produced penicillins to semi-synthetic penicillins Some resistant microorganims arent resistant to semi-synthetic penicillins |
Glucose isomerase | V. commonly use to produce HFCS, sweeter than sucrose and can be used in diet fods Glucose ---> fructose |
Lactase | Hyrolyses lactose into glucose and galactose so lactose-intlerant people can drink milk and reduce the risks of developing osteoporosis as a lack of calcium |
Aminoacylase | N-acyl-amino acids ---> pure sample of L-amino acids | Used in synthesising pharmaceutical compounds |
Glucoamylase | Dextrins ---> glucose | Immobilised and used to digest sources of starch e.g. corn and cassava |
Nitrile hydratase | Nitriles ---> amides Acrylamide can be polymerised to form a plastic and a gel for electrophoresis Used to treat water, helps to stick many small contaminanrts together so they can be filtered out |
Supporting surfaces | Glass Porous carbon Clay |
Advantages of immobilising enzymes | Lowers temp required No contamination of end product Reusable Protected by immobilisng matrix so high temp or extreme pH has no effect |
Disadvanages of immobilising enzymes | Expensive to set up Bonding may affect active site Contamination is v. costly as whole system needs to stop Slower process as enzymes and substrates don't mix freely |
Making yoghurt | Milk is fermented by bacteria Lactose---> lactic acid Low pH denatures caesin, causing milk to coagulate and thicknes Also adds flavour |
Makng cheese | Milk is fermented by bacteria Lactose --> lactic acid, acidifies milk Rennin coagulates caesin in the presence of Ca2+ Resulted curd separates from liquid whey by curdling, stirring and heating |
Microorganisms in baking | Flour is mxed w. water, salt and yeast | Respires anaerobically and produces CO2 bubbles, causing the dough to rise |
Making wine | Grapes have yeast on the surface | When crushed uses glucose and fructose to respire and produce CO2 and alcohol |
Making beer | Uses malted barley grains that are beginning to germinate Stored starch to maltose, respiratory substrate for yeast Produces CO2 and alcohol |
Making penicillin | Fermentation of fungus as a batch culture for 6-8 days Secondary metabolite Once fermentation is complete, culture is filtered to remove cells Antibiotics precipitated and purified |
Making insulin | Genetic modification of bacteria | Grown in fermenters, continuous culture |
Why is the Sheep C treated w/ hormones | Increase thickness and vascularisation of uterine lining |
How can SCNT help save endangered species | Doesn't require fertile females Female not put at risk during mating Can subdivide successfully formed embryo |
Economic advantages of immobilising enzymes | Reusable so less money required | Higher temp means profit from faster yield |