SUMMARY SHEETBIOTECHNOLOGY

SUB TOPIC (a) LIVING FACTORIES

Biotechnology is using living organisms to: 1 produce a product for human consumption or 2 carry out a process, of benefit to humans.

GENERAL

State that the raising of dough and the manufacture of beer and wine depend on the activities of yeast.

Identify yeast as a single-celled fungus, which can use sugar as food.

Using a word equation, state the process of fermentation of glucose by yeast.

Fermentation is another name for the production of energy from food without using oxygen.

When yeast ferments glucose the process can be represented by the following word equation:-

Glucose + yeast carbon dioxide + alcohol + little energy

State that the manufacture of cheese and yoghurt depends on the activities of bacteria.

Making cheese and yoghurt are also processes which depend upon micro-organisms - in this case bacteria.

Cell wall

Cell membraneCytoplasm

Nucleus

Yeast is a tiny single-celled fungus. It is used in bread making (raising of dough) and brewing of beer, wine and other alcoholic drinks.

Yeast cells contain a cell wall, cell membrane, cytoplasm and a nucleus.

Yeast is a single celled, microscopic fungus which uses sugar as food.

During bread making the baker is interested in the carbon dioxide the yeast produces.

This gas makes the dough rise before baking. A brewer is interested in both the alcohol and the

carbon dioxide made by the yeast. Beer is expected to be alcoholic and the carbon

dioxide gives the characteristic fizz.

Cheese

Bacteria are added to the milk to make it go sour. Next an enzyme called rennin is added to make the milk clot.

Rennin breaks down the proteins in milk and forms the solid curd.

The liquid whey is then drained off. The curd is finally allowed to ripen and mature to form cheese.

Some cheeses are then flavoured by adding different bacteria. Blue cheeses have fungi added to them to produce the blue veins and characteristic colour.

Yoghurt

Two strains of bacteria are used to make yoghurt. They ferment the milk sugar (lactose) into lactic acid. This acid makes the milk curdle and go lumpy and gives yoghurt its sour taste.

Bacteria are also used to clot or thicken the milk.

State that the souring of milk is a fermentation process.

The production of lactic acid by milk bacteria is another type of fermentation. This is souring of milk. The souring of milk is a fermentation process, as it takes place better when

oxygenis absent.

CREDIT

Describe the process of anaerobic respiration and compare it with aerobic respiration.

Respiration is the release of energy from food and takes place in every living cell. Most cells use oxygen to make this energy release efficient. This is AEROBIC RESPIRATION.

Some cells, however, can respire without oxygen. This is called ANAEROBIC RESPIRATION and it is less efficient as it releases less energy from the food than aerobic respiration. Fermentation by yeast is an example of anaerobic respiration.

  Aerobic AnaerobicOxygen required Yes NoAmount of energy released

More Less

End products Carbon dioxide and water Carbon dioxide and alcohol

Aerobic Respiration

Glucose + Oxygen Carbon dioxide + Water + lots Energy

Anaerobic Respiration

Glucose + Yeast Carbon dioxide + Alcohol + little Energy

Describe how commercial brewers provide the best growing conditions for yeast.

A fermenter is a vessel which can be used to manufacture a range of products in the presence or absence of oxygen.

Yeast can be used to ferment sugars to produce many useful substances for man.

Explain what is meant by the term “batch processing”.

This is the technique used by commercial brewers to provide the best conditions for fermentation.

The common feature of all batch processes is that they involve closed systems. After the addition of the raw materials, nutrients and yeast culture, the system is left untouched, although controlled, until fermentation ends.

The beer is then removed. Fermentation ends because nutrients run out or waste materials build up. The growth rate of the yeast is therefore higher at the start, falling to zero at the end.

For efficient brewing, the best conditions for yeast must be provided. These are;

1. plenty of food (glucose)2. the correct temperature (10 -18oC)3. Correct pH (7)4. Controlled oxygen supply (in aerobic

conditions)5. sterile conditions

Batch processing which is monitored and controlled to give optimum conditions maximises the quality and quantity of the beer.

One disadvantage of this system is that it must be thoroughly cleaned out between batches. This is time in which no product is being made and so no money is being earned!!

Explain the need for malting of barley before use by the brewing industry.

Barley is used as the source of food for alcoholic fermentation by yeast in the brewing industry. The carbohydrate in barley is in the form of starch which must be converted to sugar before yeast can use it.

Enzymes in the barley grains convert the starch to maltose during germination. In the brewing industry this process is called malting the barley.

Explain the souring of milk in terms of bacterial fermentation of lactose.

Fresh milk contains sugars and some bacteria. The bacteria feed on the sugars in the milk in the absence of oxygen (anaerobic respiration).

The main sugar in milk is called lactose. Lactose is converted into lactic acid by bacterial fermentation, the increased acidity makes sours and thickens the milk.

Souring of milk is a fermentation process.

Lactose Lactic Acid (sugar in milk) (causes souring)

SUMMARY SHEETBIOTECHNOLOGY

SUB TOPIC (b) PROBLEMS AND PROFIT WITH WASTE

GENERAL

Describe some examples of the damage caused to the environment by disposal of untreated sewage.

The disposal of untreated sewage causes damage to the environment, for example:

Bacteria feed on the sewage and use the oxygen in the river for respiration. This lowers the oxygen concentrations of rivers and lowers their pH (i.e. makes the by river more acidic) Organisms that require oxygen are killed e.g. fish.

Give examples of diseases which may be spread by untreated sewage.

Untreated sewage can also spread diseases caused by harmful micro-organisms Such diseases include:- typhoid, food poisoning, polio, dysentery and cholera.

Describe the principle precautions to be taken during laboratory work with micro-organisms.

Microbes must be handled with great care to avoid contamination Contamination is:-

- the introduction of unwanted microbes into cultures - the spread of microbes that cause disease.

It is very important to take careful precautions when working in the laboratory with micro-organisms.

Some of the main precautions are: The bench is thoroughly cleaned with disinfectant. Hands are washed. No food or drinks in the lab.

There is a rise in organisms (indicator species) that can survive an anaerobic environment e.g.:

Sludge worms. Blood worms. Rat tailed maggots. Further downstream the

bacteria use up the food source and the river reverts to its normal state.

Sterilising lab benches and use of sterilised equipment by heating glassware to 121oC for 20 minutes in an autoclave to ensure all the bacteria are dead.

The wire loop is heated in a blue bunsen flame to kill all unwanted Microorganisms. Biohazard signs should always be displayed when working with Microorganisms. No eating and drinking signs should also be displayed.

Explain the importance of such precautions in biotechnological processes whenever relevant.

Precaution ReasonUSE OF DISINFECTANTUSE OF HEAT

TO KILL UNWANTED MICROBES

LAB. COATS WORNHANDS WASHED/GLOVES WORNCULTURES SEALED

TO AVOID CONTAMINATION

State that the main process in the treatment of sewage is its breakdown by the action of decay micro-organisms to products harmless to the environment.

In developed countries most sewage water is treated before it is reused or released into rivers or the sea.

Sewage water is treated at sewage works. These vary in size and design but use the same basic process. In sewage treatment works, the main process is the breakdown of the waste by

the action of decay micro-organisms to products harmless to the environment.

Describe how the oxygen required by micro-organisms can be provided during sewage treatment.

Sewage-eating bacteria need oxygen. This can be provided in three ways: Trickling the sewage through filter beds. Air spaces between the stones provide

oxygen. Bubbling compressed air through tanks containing activated sludge (sewage with

added sewage-eating bacteria). Stirring the sludge which mixes the oxygen from the air.

Give two examples of useful products and the waste materials from which they are gained through the action of micro-organisms and explain the economic importance of this technology.

Upgrading waste is a way of obtaining useful products such as high quality protein foods and biogas fuel.

These are obtained from unwanted waste materials through the action of micro-organisms.

waste Useful product Economic importance advantagesManure Methane gas

(biogas)Prevents pollution from waste Fuel source

Methanol protein Saves cost of disposal Food source

This technology is important economically because useless, and possibly even poisonous substances are converted into useful substances such as food and fuel.

The main aim in upgrading waste is to convert it to more useful substances. Most commonly this involves raising the levels of protein, or increasing

the energy content of the waste.

State that alcohol and methane are products of fermentation.

There are advantages in using fermentation fuels rather than fossil fuels (coal, oil or gas).

A fuel is something that can be burned to release energy. Alcohol and methane are both valuable fuels produced by fermentation by bacteria

in the absence of oxygen. Each of them can he produced by fermentation of suitable plant crops. Alcohol – by fermentation of sugar by yeast. Methane – by fermentation of waste by bacteria.

Fermentation

Fermentation is an energy releasing process. This is carried out by some microbes in the absence of oxygen. Alcohol and methane gas are products of fermentation.

YEASTGlucose Alcohol + Carbon dioxide + Energy

Explain the advantages of deriving fuel through fermentation rather than from fossil sources.

Fermentation uses raw materials which are renewable as opposed to fossil fuels which must run out eventually.

It allows countries with no coal or oil to produce their own fuel. The raw materials used may often be the waste from other production processes

which could otherwise be harmful or difficult to dispose of. Burning them produces less atmospheric pollution than fossil fuel.

FERMENTATION FUELS FOSSIL FUELSHarmless to the environment Harmful to the environmentEasy to obtain Difficult to obtainCheap to obtain Expensive to obtainRenewable Non-renewable

State that under suitable conditions, micro-organisms can reproduce very rapidly by asexual means.

When conditions are suitable (e.g. good food supply, suitable temperature) microbes reproduce rapidly by ASEXUAL means.

Most micro-organisms reproduce themselves much faster than the cells of plants and animals.

State that microorganisms may have harvested to provide protein rich food for animals or man.

Industry is able to use fast growing micro-organisms to manufacture food, especially protein.

These micro-organisms can be harvested to provide protein rich food for animals or man.

Given food, water and heat, one bacterium can result in many hundreds of bacteria within a few hours.

Bacteria can be grown, harvested and dried to form a protein-rich powder called single-celled protein which is used as animal feed.

Mycoprotein (Quorn) is made from a fungus and is a useful source of protein for vegetarian.

CREDIT

Explain the precautions which are taken during manufacturing processes with reference to resistant fungal and bacterial spores.

Conditions e.g. Microbial activityfavourable 20-40°C Multiply and grow, no spores producedunfavourable 100°C No growth, but form resistant spores

Precautions during manufacturing processes are just as important. Contamination by bacteria and fungi can spoil the quality and flavour of the

product.

Resistant spores are produced by microbes in certain conditions.

The spores are highly resistant to environmental stresses such as high temperatures, acids, and disinfectants. 

Manufacturing processes must kill spores or prevent their entry in order to avoid contamination e.g. sterilisation at 125OC.

A particular danger in these cases are spores of bacteria and fungi which are resistant to normal hygiene measures.

Very high temperatures and chemical methods are often used for sterilisation. Careful and regular checks must be made for contamination.

Explain why complete breakdown of sewage is only possible in aerobic conditions.

The reason for providing lots of oxygen to the bacteria in sewage treatment works is that:

Anaerobic respiration by bacteria only partly breaks down the waste and is a less efficient process.

The sewage is still unsafe. Plentiful oxygen means that the bacteria use aerobic respiration Aerobic respiration makes the breaking down process complete producing carbon

dioxide and water which is safe.

Explain why a range of micro-organisms is needed to break down the range of materials in sewage.

Sewage contains a wide variety of waste materials (carbohydrates, proteins, fats and minerals).

Different types of microorganism feed on different waste materials. This means that a range of different micro-organisms must be present if all the

waste is to be broken down.

Explain the advantages of upgrading waste in terms of increasing its available energy or protein levels.

Microorganisms can take low-grade waste with little energy or nutrient value and convert it to high-grade material with a higher energy content or nutrient value.

E.G. Whey from cheese making (low energy and nutrient content) can be used for fungal respiration to make cattle feed (high energy and high nutrient (protein content).

The protein levels are raised or the energy content is increased.

Describe the part played by bacteria in the process of decay and recycling of carbon and nitrogen.

When a plant or animal dies its tissues decay. This is mainly due to the actions of microbes. These microbes use the dead animal or plant material as a food source to obtain

energy.

Explain the process of decay in terms of the energy requirements of micro-organisms.

Decay is both important and useful, since it recycles raw materials and gets rid of waste at the same time.

Decay is the decomposition of organic matter by decomposer micro-organisms. Bacteria and fungi feed on the organic matter to provide themselves with energy. During the decay process both carbon and nitrogen are recycled. The carbon from dead or waste materials is made into carbon dioxide which plants

need for photosynthesis. The nitrogen from proteins in dead or waste materials is converted to nitrates in

the soil which plants use to produce new proteins.

The Carbon Cycle

The Nitrogen Cycle

Nitrogen in the air is a very unreactive gas.

In nature plants in particular need nitrogen in the form of nitrates to make protein. Animals can then digest this plant protein to make animal protein for their own

growth. Bacteria are needed in the nitrogen cycle in nature.

Much of the world's carbon is combined in rocks:

This means that carbon is in short supply.

In nature it must be recycled.

Bacteria and fungi are needed in the carbon cycle in nature.

SUMMARY SHEETBIOTECHNOLOGY

SUB TOPIC (c) REPROGRAMMING MICROBES

GENERAL

State that normal control of bacterial activity depends on its chromosome material.

Genetic Engineering is very important to biotechnology. It directs microbes (bacteria) to make products they would not normally make. E.g. genes (pieces of chromosome) from human cells can be placed into microbes

to make substances useful to humans. The control of all the normal activities of a bacterium depends upon its single

chromosome and small rings of genes called plasmids.

State that pieces of chromosome can be transferred from a different organism and so allow bacteria to make new substances.

In genetic engineering pieces of chromosome from a different organism can be inserted into a plasmid.

The plasmids can multiply and instruct the cells to make products useful to humans.

Give some examples of the products of genetic engineering, and their applications, e.g. insulin.

Nitrogen inthe air

animal protein

dead plants & animalsurine & faeces

ammonia

nitrites

nitrates

plant madeprotein

decomposition by bacteria & fungi

bacteria

(nitrifying bacteria)

nitrates absorbed

denitrifyingbacteriaroot nodules

(containing nitrogen fixing bacteria)

nitrogen fixing planteg pea, clover

bacteria

PRODUCT APPLICATIONINSULIN TREATMENT OF DIABETESGROWTH HORMONE TREATMENT OF HORMONE

DEFICIENCY

Other important products of genetic engineering are antibiotics and vaccines. Antibiotics are chemicals that can kill certain microbes. Using the technique of

genetic engineering existing antibiotics can be made even more effective in the fight against disease.

Vaccines are used to prevent disease. Thanks to genetic engineering better vaccines can be produced more easily.

State that “biological” detergents contain enzymes produced by bacteria.

Biological detergents contain protein digesting enzymes produced by genetically engineered bacteria.

Many of the stains on clothes, like blood, sweat and food, are proteins.

State that an antibiotic is a chemical which prevents growth of micro-organisms.

In 1928 a Scotsman called Alexander Fleming discovered that a substance made by a fungus prevented growth of some bacteria.

This substance was named penicillin and was the first known antibiotic (a chemical which kills microorganisms).

Since then many other antibiotics have been discovered and used against diseases caused by bacteria.

In the past, one way to remove stains was to boil the fabric in water with a detergent.

Many modern man-made fabrics however, are damaged by high temperatures.

Also the heat energy used is expensive. Some detergents are called “Biological” and offer a solution to

these problems.

CREDIT

Explain genetic engineering in terms of manipulation of chromosomal material.

State that as a result of genetic engineering, bacteria may produce increased quantities of products and speed up processes.

Antibiotic

Zone of no growth : Antibiotic has stopped the bacteria from growing

Growth of Bacteria

1. An enzyme is used to cut the human gene out of the chromosome.

2. Plasmids are then removed from bacterial cells.

3. The plasmids are cut open with an enzyme.

4. A human gene is inserted into each plasmid.

5. Plasmids are inserted back into the bacteria.

6. Bacteria with the human gene are then multiplied.

7. Each bacterium will produce a tiny volume of insulin

8. By culturing the genetically engineered bacteria limitless supplies of the useful product may be produced.

If several copies of a desirable gene are made and put into the bacterial cell, even greater quantities of the desired gene will be produced.

Sometimes a bacterium’s own genes may be copied and increased to speed up a process carried out by a bacterium.

For example, some bacteria can break down oil spills. If several copies of the gene involved are inserted, the bacterium will be able to

clean up an oil spill much faster.

Explain some of the advantages of genetic engineering, compared with selective breeding, in producing mew genotypes to create the best organism for a particular function.

Genetic engineering is a way of producing organisms which have genotypes best suited for a particular function.

In the past man has used selective breeding to achieve this. This was done by choosing only his most suitable animals and plants for breeding. Genetic engineering has several advantages over selective breeding. Some are: particular single characteristics can be selected the selection may be quicker a desirable characteristic can be transferred from one species to another

  Genetic Engineering Selective BreedingNumber of Generations required for change

One Many

Time taken to produce improved variety Quick SlowChance that desired change will occur Very good PoorQuality and quantity of product Excellent Variable

There are dangers involved with genetic engineering since it involves creating completely new strains of bacteria.

There is a possibility of creating some which are harmful to animal or plant life.

Explain the ever increasing need for insulin produced by biotechnology.

Insulin is a “chemical messenger” (hormone) produced in the pancreas. It keeps the blood sugar at the correct level. Some people cannot produce insulin and suffer from the disease diabetes. The increase in world numbers of people suffering from diabetes and also

the fact that diabetics are living much longer, has increased the demand for insulin.

Animal insulin could therefore be in short supply, whereas genetically engineered insulin can be produced in any quantity required to meet the needs of diabetics.

Cattle and pig insulin are different in structure from human insulin and in some diabetics can bring about an allergic response.

This may have long-term side effects such as eye and liver damage. Genetically engineered insulin has almost exactly the same structure as human

insulin and therefore allergic responses are less likely to occur. Some diabetics do not like injecting themselves with insulin that comes from

animals and prefer the ‘human’ insulin produced by bacteria.

Describe the advantages of using the low temperature enzyme reactions of “biological” detergents.

Biological detergents have a number of advantages: The enzymes work at relatively low temperatures. They remove stains which would otherwise need high temperature washes. Energy and money are saved by allowing low temperature washes. They also help to get delicate fabrics, which would be damaged by a hot wash,

properly clean.

Explain the action of “biological” detergents in terms of digestion by enzymes.

The enzymes in the detergent help to break down (digest) stains caused by proteins.

The stains are digested by the enzymes into soluble substances, which can be washed away.

These enzymes are produced by bacteria and then added to the washing powder.

Explain why a range of antibiotics is needed in the treatment of bacterial diseases.

- .

Describe the advantages of using immobilization techniques.

Enzymes are used in many manufacturing processes to convert raw materials into a product.

Even with genetic engineering, enzymes may still be expensive to produce. To increase profit, the enzymes should be used may times if possible. In an industry using enzymes, separation of products and enzyme can be

expensive and the enzyme may not be re-usable. In most enzyme reactions the following takes place:

Antibiotic has not worked : Bacteria are RESISTANT to the antibiotic

A RANGE OF ANTIBIOTICS ARE NEEDED TO TREAT BACTERIAL DISEASES BECAUSE:-

- Each one is only effective against certain bacteria.

- Patients may be allergic to a particular antibiotic.

Bacteria can become resistant to a particular antibiotic.

Substrate + enzyme mixture product + enzyme mixture

It would be an advantage therefore, if the enzyme could be easily separated from the product and enzyme mixture.

This can be achieved by trapping the enzyme in jelly (or glass) beads. This allows the enzymes to be easily recovered and separated from the end

product. Enzymes, or even cells, which are treated in this way are said to be immobilised.

Advantages

- Products are easily separated.- No time wasted in setting up another system.- There is less waste.

Explain how continuous-flow processing is allowed by using immobilization and the advantages this has over batch processing.

Not only enzymes can be immobilised. Some whole cells can be trapped in the same way, e.g. yeast. This allows the alcohol and yeast to be easily separated at the end of the

fermentation process. Immobilised yeast can be used in a “continuous-flow” process rather than using

batch processing.

Process of Continuous Flow Processing1. Substrates (raw materials) are poured into the fermenter vessel at the bottom in a steady stream.2. The raw materials trickle over the enzymes which are held onto by jelly beads in the fermenter vessel.3. The enzymes act on the raw materials to produce the product which constantly trickles out at the top of the vessel.

Advantages over Batch Processing

Very large quantities of product are produced quickly and cheaply in a continuous process.

There is no need to separate the product from the enzyme that produced it.

The enzyme (which is probably expensive) gets used for a long time and is not lost in the process.

There is no need for frequent cleaning of the fermenter vessel as in a batch process, so there is less time lost during which no product is being made.