Living Factories
Identify yeast as a single-celled fungus which can use sugar as food
Yeast is a microscopic fungus found naturally
on many types of fruit such as grapes.
A yeast cell is made of a single cell. Yeast can
use sugar (glucose) as a food supply.
Using a word equation, state the process of fermentation of glucose by yeast
Yeast is used to make many useful products. Its usefulness comes from its ability to
use glucose as a source of energy. It does this in a process called fermentation.
The word equation for fermentation is:
Glucose  energy + carbon dioxide + ethanol
State that the raising of dough and the manufacture of beer and wine depend on the
activities of yeast
When yeast ferments, it makes two important products, ethanol
and carbon dioxide. In baking the carbon dioxide bubbles make
the dough rise. The ethanol is burned off during the baking
process.
State that the souring of milk is a fermentation process
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State that the manufacture of cheese and yoghurt depends on the activities of
bacteria
Cheese and yoghurt are made by curdling milk. Lactic acid is
needed to curdle the milk.
Manufacturers add certain strains of bacteria to the milk.
Different types of bacteria are used to give the different
types of cheese and yoghurt.
Problems and profit with Waste
Describe some examples of the damage caused to the environment by disposal of
untreated sewage
Sewage is mostly organic waste and it is produced in large amounts by humans. To avoid
disease, it must be dealt with safely and quickly.
The release of untreated sewage into waterways causes the pH of the water to
decrease and also causes a fall in the oxygen content of the water.
Give examples of diseases which may be spread by untreated sewage
In the first half of the 19th Century, disease and death in Britain
as a result of untreated sewage entering water. Even in modern
Britain, natural disasters like flooding could disrupt the sewage
treatment systems and the threat of such disease could return.
Some of the diseases which can be spread by untreated sewage
or failure to wash hands after a visit to the toilet are:
typhoid
diptheria
polio
food poisoning
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cholera
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
Describe how the oxygen required by micro-organisms can be provided during sewage
treatment
Oxygen is required by the micro-organisms and this is usually provided at the
treatment works using compressed air or by trickling the sewage over stones which
trap pockets of air.
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Describe the principle precautions to be taken during laboratory work with microorganisms
Microbes can help in the production of food and drink, the treatment of sewage or can
cause disease. Micro-organisms are found everywhere so precautions must be taken to
prevent unwanted microbes from growing (contamination).
Safe-practice
Petri dishes of agar jelly must be
kept closed until you are ready to
use them to stop microbes from
the air contaminating the plates.
you wash your hands before and
after the experiment to stop you
contaminating the agar plates and
then to stop you spreading the
microbes around.
Petri dishes are sealed with tape
after being inoculated to stop
microbes escaping.
After use the petri dishes are treated in an autoclave to kill the microbes.
Explain the importance of such precautions in biotechnological processes whenever
relevant
Contamination is the presence of unwanted, perhaps harmful, micro-organisms. Beer
production is one area where contamination may occur.
Between batches beer manufacturers’ sterilise their equipment.
State that alcohol and methane are products of fermentation
Methane and alcohol can be used as fuels and are known as fermentation on fuels.
Explain the advantages of deriving fuel through fermentation rather than from fossil
sources
There are advantages in using fermentation fuels rather than fossil fuels.
Fossil fuels are coal, oil and gas.
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Fermentation fuels
Fossil fuels
Harmless to the environment
Harmful to the environment
Easy to obtain
Difficult to obtain
Cheap to obtain
Expensive to obtain
Renewable
Non - renewable
Give 2 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 means of obtaining useful products from unwanted waste
material which would otherwise have to be disposed of and might harm the environment.
Two examples of useful products are:
1
Biogas
This can be made from the degradation of farm manure and household rubbish by
microbes. The biogas can then be used as a source of energy.
2
Whey and fruit pulp
Whey is the waste from cheese making and fruit pulp the waste from making fruit
juice.
Both of these food left-overs can be converted by micro-organisms to high quality
protein foods for e.g. cattle feed.
State that under suitable conditions, micro-organisms can reproduce very rapidly by
asexual means
Most micro-organisms can reproduce much faster than plant and animal cells can by
asexual reproduction.
State that micro-organisms may be harvested to provide protein rich food for animals
or man
Large quantities of micro-organisms can be used to provide protein rich food for
animals and man e.g. single cell protein or mycoprotein.
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Reprogramming Microbes
State that the normal control of bacterial activity depends on its chromosomal material
Bacterial cells are much smaller than animal cells. Both bacteria and animal cells have a
nucleus. Some bacterial cells have extra chromosome material called plasmids that can
be transferred from one bacterial cell to another. Just like other cells, the normal
control of the bacterial cell’s activities depend on its chromosomal material.
Bacterial cell
Chromosome
plasmid
State that pieces of chromosome can be transferred from a different organism and so
allow bacteria to make new substances
Genetic engineering alters microbes so that they will make products they would not
normally make.
A number of steps are involved:
1 The chromosomal material is removed from an animal cell
2 One gene is removed
3 A plasmid is carefully removed from a bacterial cell and the ring is carefully
opened
4 The gene from the animal cell is inserted into the plasmid
5 The altered plasmid is placed back into the bacterial cell
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Give some examples of the products of genetic engineering and their applications, e.g.
insulin
Growth hormone is given to children who would not otherwise grow properly.
Insulin is used to treat diabetics who cannot make their own.
State that “biological” detergents contain enzymes produced by bacteria
Some detergents are called biological detergents as they contain enzymes
Comparing non-biological and biological washing powders
Temperature (C)
20
40
100
Biological powder
Stain gone
Stain gone
Stain present
Non-biological powder
Stain partly present
Stain partly present
Stain gone
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 the growth of some bacteria. This substance was named penicillin
and was the first known antibiotic. Since then many other antibiotics have been
discovered and used against diseases caused by bacteria.
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