OCR A Level Biology Biotechnology

What is biotechnology?

Applying biological organisms or enzymes to the synthesis, breakdown or transformation of materials in the service of people

What are 5 examples of biotechnology?

1. Using yeast to make alcohol

2. Using yeast to make bread

3. Using fungi to make antibiotics

4. Using bacteria to clean up oil spills

5. Enzymes in biological washing powders

What are the 3 main types of organisms used in biotechnology?

1. Bacteria

2. Yeast

3. Fungi

What are 6 reasons we tend to use microorganisms in biotechnology?

1. No welfare issues

2. Enormous range of microorganisms

3. Can be manipulated easily to do reactions which they wouldn't naturally

4. Microorganisms have very short life cycle and grow rapidly, so lots can be grown

5. Nutrient requirements often simple and cheap

6. Due to simple conditions needed, these too are often cheaper than in non-biological processes

What are 5 disadvantages of using microorganisms in food production?

1. Conditions needed for their growth are often very similar to those which microorganisms which make food go off prefer

2. They are often GM, so ethical concerns

3. If conditions aren't right then the food might not be produced correctly

4. Often need sterile conditions

5. Protein has little flavour so needs additives

How does yeast make bread rise?

They aerobically respire and the carbon dioxide thus produced makes the bread rise

How does yeast make alcohol?

They anaerobically respire, using the food provided, and in doing so make ethanol

What 2 compounds are formed by bacteria in yoghurt production?

Ethanol and lactic acid

What effects do bacteria have on the physical properties of yoghurt and how?

Produce extracellular polymers which make yoghurt more smooth and thick

What 2 things do bacteria do in cheese making?

1. Feed on lactose in milk, changing the taste and texture

2. Outcompete bacteria which could cause the milk to go off

What is single-cell protein?

Edible protein produced by microorganisms

What is the best-known example of single-cell protein?

Quorn

What fungus is used to make Quorn?

Fusarium venenatum

Is the Fusarium v. fungus itself eaten as Quorn?

No, it produces a protein which is combined with egg white to make Quorn

What is food security?

Having enough food to feed a population, with the population being able to access this food and have a balanced diet

What is used as a food source for Fusarium v.?

Glucose syrup

What 3 types of microorganisms have been used to try to make protein substitutes in the past?

1. Fungi

2. Algae

3. Bacteria

What are 2 reasons people argue that more vegetarian diets would increase global food security?

1. Vegetables are cheaper, and therefore more accessible

2. A vegetarian diet is more efficient as it involves fewer trophic levels

What are 6 advantages of using microorganisms in human food production?

1. Grow and produce protein fast

2. High protein content with little fat

3. Can use a wide variety of waste as food

4. Can be genetically modified

5. Can be made to taste like anything

6. Production is constant on not dependant on weather, breeding cycles etc.

What are 2 examples of medicines produced via biotechnology?

Insulin and penicillin

What type of microorganism is used to produce penicillin?

A mould

What are 4 factors which affect how penicillin is grown commercially?

1. Mould is sensitive to pH

2. Mould is sensitive to temperature

3. Mould needs rich nutrient medium

4. Mould needs quite high oxygen levels

What are 5 features of the penicillin production process which optimise the rate of production?

1. Buffers in the nutrient medium to keep a constant pH of around 6.5

2. Relatively small fermenters used as it's hard to keep larger bioreactors sufficiently oxygenated

3. Mixture constantly stirred for oxygenation

4. Rich nutrient medium used

5. Temperature kept constant

What style of manufacturing is used to make penicillin?

Semi-continuous batch maufacturing

What are the 3 stages of penicillin production?

1. Fungus grows

2. Penicillin produced

3. Drug extracted from the medium and purified

How was insulin extracted before biotechnology?

Usually from the crushed up pancreases of pigs or cattle slaughtered for meat

What were 4 problems with extracting insulin from the crushed pancreases of dead animals?

1. Some were allergic to animal insulin as was often impure

2. Some faith groups forbid pig or cow products

3. Action of animal insulin peaks a few hours after injection

4. Supply erratic and depended on demand for meat (as animal pancreases usually came from stuff slaughtered for meat)

How was the problem of people being allergic to animal insulin eventually alleviated (whilst still using animal insulin)?

Very pure forms were developed which meant that less people reacted badly

What are the 2 approaches to bioremediation?

Using natural and using GM organisms

What happens in bioremediation?

Microorganisms are used to break down pollutants and contaminants in the soil and water

What is an example of GM bacteria being used for bioremediation?

Bacteria which were genetically modified to break down mercury

What are 2 examples of non-GM bacteria being used for bioremediation?

1. Usage in cleaning up oil spills

2. Usage in cleaning up sewage and killing the pathogens contained within it

Currently, are GM or non-GM bacteria more successful at bioremediation?

Non-GM, although the gap is narrowing

Where does bioremediation take place?

Often at the site of the contamination, but sometimes stuff is removed to be decontaminated

What is culturing microorganisms?

Growing large quantities

What are 2 reasons health and safety procedures must always be followed when culturing microorganisms?

1. Even if they are nominally harmless, mutations are always a possibility and could lead to a microorganism becoming pathogenic

2. There may be contamination from pathogenic microorganisms

What 4 things do microorganisms being cultured need?

1. Food

2. The right pH

3. Enough oxygen

4. The right temperature

What is the food which is given to cultured microorganisms called?

Nutrient medium

What are 3 good protein sources which nutrient mediums can be infused with?

1. Blood

2. Yeast extract

3. Meat

Do all microorganisms need a precise nutrient balance for their nutrient medium?

No, some do but others just need a good source of protein

What are the 2 forms a culture's nutrient medium can be in?

1. Liquid (broth)

2. Solid (agar)

What is important about the nutrient medium when culturing microorganisms?

That it be kept sterile

What do enriched nutrient media allow?

Samples containing a small number of organisms to multiply rapidly

What are the 4 steps for inoculating broth?

1. Make suspension of bacteria to be grown

2. MIx known volume with broth in flask

3. Stopper flask with cotton wool

4. Incubate at suitable temperature, shaking regularly to oxygenate broth

What is inoculating?

Adding bacteria to a nutrient medium

Why is the flask stoppered with cotton wool when inoculating broth?

To prevent contamination from the air

What are the 5 steps for inoculating agar?

1. Sterilise inoculating loop by heating until red hot, then make sure it doesn't touch anything while cooling

2. Dip loop in bacterial suspension

3. Remove lid of agar dish and streak the loop across the surface, taking care it doesn't dig in

4. Replace lid and loosely hold down with tape

5. Incubate at suitable temperature

What pattern does a bacterial culture's growth follow?

A standard population growth curve

What are 5 limiting factors which prevent exponential growth of bacteria?

1. Nutrient availability

2. Oxygen levels

3. Temperature

4. Waste buildup

5. pH change

What are 6 things any microorganism used in any bioprocess must do?

1. Not mutate easily

2. Not produce poison to contaminate the product

3. Work reasonably fast

4. Do the reaction needed

5. Give a good yield of product

6. Use quite cheap nutrients and conditions

What are primary metabolites?

Products necessary for microbial growth

What are secondary metabolites?

They are molecules that are not essential for growth and so in the short term the microorganism would not suffer without them

What are 2 of the main ways of growing microorganisms?

1. Batch fermentation

2. Continuous fermentation

What are 2 examples of secondary metabolites?

1. Pigments

2. The chemicals which plants produce to protect against herbivory

What are 4 examples of primary metabolites?

1. Amino acids

2. Organic acids

3. Alcohol

4. Certain enzymes

What are 4 stages of batch fermentation?

1. Microorganisms inoculated into a fixed volume of medium

2. As growth occurs, nutrients used up and waste products and biomass accumulate

3. Culture reaches stationary phase- overall growth ceases, but microorganisms will often carry out biochemical changes to make necessary products

4. Process stopped before death phase and products harvested

What are 3 stages of continuous fermentation?

1. Microorganisms inoculated into sterile nutrient medium and start to grow

2. Sterile nutrient medium added continuously to culture once exponential growth reached

3. Culture broth continually removed, keeping culture volume in bioreactor constant

What does continuous culture enable?

Continuous balanced growth

Levels of what 3 things are kept more or less constant in continuous fermentation?

1. Nutrients

2. pH

3. Metabolic products

What are most bioreactor systems optimised for?

Maximum production of metabolites

What 2 things can bioreactors be optimised for?

1. Maximum production of biomass

2. Maximum production of metabolites

What 2 things is continuous culture used for?

1. Some waste water treatment

2. Production of single-celled protein

What type of culture do the majority of industrial processes use?

Batch or semi-continuous

What is used to separate out the useful stuff from in a bioreactor?

Downstream processing

All bioreactors produce a mixture of what 5 things?

1. Possibly secondary metabolites

2. Primary metabolites

3. Unused nutrient broth

4. Microorganisms

5. Waste products

What is one of the most difficult parts of the bioprocess?

Downstream processing

What 5 things are controlled within bioreactors?

1. Nutrients

2. Asepsis

3. How well the contents are mixed

4. Temperature

5. Oxygen

What are 4 advantages of using isolated enzymes instead of whole organisms?

1. Maximised efficiency

2. Less wasteful

3. More specific

4. Purer product, so less downstream processing

What are 4 reasons most isolated enzymes for industrial processes are extracellular?

1. They are easier to get and use than intracellular enzymes as they are secreted

2. Tend to be more robust than intracellular

3. Cheaper than intracellular

4. Most microorganisms produce much fewer extracellular than intracellular enzymes, so they are easier to isolate

What are most enzymes used in industrial processes?

Extracellular enzymes produced by microorganisms

Why are isolated intracellular enzymes sometimes still used?

As there are a larger range of them than extracellular enzymes they sometimes provide the perfect enzyme for a particular reaction

What are 3 examples of intracellular enzymes used in industry?

1. Asparaginase for cancer treatment

2. Glucose oxidase for food preservation

3. Penicillin acylase for converting natural penicillin into more effective semi-synthetic drugs

When might enzymes be lost in an industrial process?

If they are free rather than immobilised

What is an immobilised enzyme?

One which is attached to inert support structure, over which the substrate passes

Why are immobilised enzymes an example of technology mimicking nature?

In actual cells enzymes are often bound to membranes in a similar fashion

What are 5 advantages of using immobilised enzymes?

1. Immobilised enzymes can be reused

2. Enzymes are more easily separated from products and reactants, so less processing

3. More reliable than free enzymes

4. Greater temperature tolerance

5. Greater ease of manipulation

What are 4 disadvantages of using immobilised enzymes?

1. Reduced efficiency

2. Higher initial costs of materials

3. Higher initial costs of bioreactor

4. More technical issues

What are 4 ways in which enzymes can be immobilised?

1. Surface adsorption to inorganic carriers

2. Covalent or ionic bonding to inorganic carriers

3. Entrapment in a matrix

4. Membrane entrapment in microcapsules or behind a semi-permeable membrane

What are 3 advantages of using surface adsorption to immobilise enzymes?

1. Simple and cheap

2. Can be used with a wide variety of processes

3. Enzymes widely available to substrate with virtually unchanged activity

What is a disadvantage of using surface adsorption to immobilise enzymes?

Enzymes can easily be lost from matrix

What are 4 advantages of covalent or ionic bonding to immobilise enzymes?

1. Cost varies

2. Enzymes strongly bound so unlikely to be lost

3. Enzymes very accessible to substrate

4. pH and substrate concentration often have very little effect on enzyme activity

What are 2 disadvantages of covalent or ionic bonding to immobilise enzymes?

1. Cost varies

2. Active site of enzyme may be modified in process, making it less effective

What is an advantage of using matrix entrapment to immobilise enzymes?

Widely applicable to different processes

What are 4 disadvantages of using matrix entrapment to immobilise enzymes?

1. May be expensive

2. Can be difficult to entrap

3. Diffusion of substrate to and from active site can be slow and hold up reaction

4. Effect of entrapment on enzyme activity can be variable

What are 3 advantages of using membrane entrapment to immobilise enzymes?

1. Relatively simple

2. Relatively little effect on enzyme activity

3. Widely applicable to different processes

What are 2 disadvantages of using membrane entrapment to immobilise enzymes?

1. Relatively expensive

2. Diffusion of substrate to and from active site can be slow and hold up reaction

What are 6 examples of products made from immobilised enzymes?

1. Semi-synthetic penicillin

2. Fructose (from glucose)

3. Lactose-free milk

4. L-amino acids

5. Glucose syrup (from starch)

6. Plastics