Topic 5 - Biotechnology

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23 Οκτ 2013 (πριν από 3 χρόνια και 10 μήνες)

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Topic 5
-

Biotechnology


Sub
-
Topic a
-

Living Factories


You should know that:




the raising of dough and the making of beer and wine depend on the activities
of



yeast



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



fermentation is another name for the release of energy from food without
using oxygen



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


GLUCOSE + YEAST


ETHANOL (ALCOHOL) + CARBON DIOXIDE + ENERGY




the term
"respiration" describes any chemical process which releases energy
from food



there are two types, depending upon whether oxygen is available or not.


AEROBIC RESPIRATION
-

which uses oxygen

ANAEROBIC RESPIRATION
-

which happens when no oxygen is
available




aerobic respiration produces much more energy from a given amount of food



anaerobic respiration (fermentation) produces much less energy



anaerobic respiration produces alcohol (ethanol) as a waste product/by
-
product when it happens in plants or
fungi such as yeast
o
anaerobic
respiration produces lactic acid as a by
-
product when it happens in animals
and bacteria



commercial brewers make sure that beer production is as efficient as
possible by providing the best possible conditions for yeast to gr
ow and
ferment



this means that the temperature, oxygen supply and amount of glucose must
be carefully controlled, and unwanted

micro
-
organisms must be kept out.



the easiest way to make sure that this happens throughout the fermentation
is to set up all the

conditions at the start, together with the raw materials,
and then to leave the whole system closed and untouched until the
fermentation is complete



this has the disadvantage that production is only possible in batches rather
than a continuous process



a

production process like this is called "batch processing"



the brewing industry uses barley as the source of the food which the yeast
ferments to make the alcohol in beer



however barley stores food in the form of starch
-

which is a type of food
that
yeast cannot use



in order to solve this, the brewer allows the barley grains (seeds) to
germinate



enzymes in the barley then convert the starch into maltose sugar, which the
yeast can ferment



this process is called malting




making cheese and yoghurt are al
so processes which depend upon micro
-
organisms
-

in this case, bacteria.



the souring of milk
is a fermentation process



fresh
milk
contains sugars and some bacteria

the bacteria feed on the sugars in the milk

the main sugar in milk is called lactose

lactose

is converted into lactic acid by bacterial fermentation,


the increased acidity makes the milk turn sour


Sub
-
Topic b
-

Problems and Profit with Waste.


You should know
that:




the disposal of untreated sewage causes several types of damage to the
environment; for example;

it lowers the oxygen concentrations of rivers due to bacterial
action,

and lowers their pH (i.e. makes them more acidic)

untreated sewage can also spread diseases caused by poisons
and harmful micro
-
organisms
.
such diseases inclu
de:
-

typhoid,
food poisoning, polio, dysentery and cholera.



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



some of the main precautions are:

use of lab coats, overalls, gloves and masks as necessary

c
areful washing of hands

sterilising lab benches and use of sterilised equipment

no food or drinks in the lab

careful disposal of microbes using high temperatures



these precautions are needed in all biotechnological processes

to
prevent the escape

of harmful organisms
to the surroundings





to
avoid contamination

of pure cultures of microbes by





unwanted other types entering
from the surroundings



precautions during manufacturing processes are just as important



a particular danger in these case
s are spores of bacteria and fungi
which
are
resistant to normal hygiene measures.



careful and regular checks must be made for contamination



very high temperatures and
/
or suitable chemical methods are often used for
sterilisation.



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 micro
-
organisms



the micro
-
organisms feed on the organic matter to provide themselves with
energy



some bacteria [and some fun
gi) are involved in the process of decay



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 mat
erials
is
made into nitrates in
the soil which plants use as nutrient to
produce new proteins.




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.



the
micro
-
organisms need lots of oxygen to do their job properly, and this is
provided both by stirring the waste mechanically, or by injecting jets of
compressed air



the reason for the need to provide lots of oxygen to the bacteria in sewage
treatment works
i
s
that:


anaerobic respiration by bacteria only partly breaks down the waste.

plentiful oxygen means that the bacteria use aerobic respiration

aerobic respiration makes the breaking down process complete




sewage contains a wide variety of waste materials



different types of micro
-
organism feed on different waste materials



this means that a range of different micro
-
organisms must be provided so
that all the waste can be broken down.



examples of useful products which can be gained from waste materials
through

the action of micro
-
organisms are:

biogas (mainly methane) which is produced from organic waste such as
sewage sludge and domestic refuse

high quality protein foods from waste such as whey (from cheese
making) or fruit pulps (after juice extraction)




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 invo
lves raising the levels of protein, or increasing the
energy content of the waste.




alcohol and methane are both valuable fuels



each of them can he produced by fermentation of suitable plant crops



the production of fuel in this way has certain advantages o
ver the production
and use of fuels from fossil sources such as coal and oil




some of the advantages are:


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

in many cases 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 and/or
difficult to dispose of

burning them produces less atmospheric pollution than fossil
fuel




under

suitable conditions micro
-
organisms can reproduce very rapidly by
asexual methods.



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


Sub
-
Topic
c
-

Reprogramming Microbes


You should know that:




the control of all the

normal activities of a bacterium depends upon its
chromosome



in genetic engineering pieces of chromosome can be transferred from a
different organism



this allows the bacteria to make new substances



this process involves several steps



identifying useful g
enes in other organisms



separating the required gene from the rest of its chromosome



inserting the gene into a "host" cell (usually bacterial)



reproducing the cell which now contains the new chromosomal material



as a result of genetic engineering it is pos
sible to use bacteria to produce
increased quantities of many products
o
genetic engineering also speeds up
the process of producing many substances



genetic engineering
is
a way of producing organisms
which
have genotypes
best suited for a particular funct
ion.
o
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 from



genetic engineering has several advantages over selective breeding as a
method:


particular

single characteristics can be selected

the selection may be quicker

a desirable characteristic can be transferred from one species to
another




genetic engineering is used for the production of substances which used to be
both expensive and difficult to pr
oduce, examples include:


insulin for the control of diabetes

antibiotics such as penicillin

various vaccines for the control of disease




insulin
is
a particularly successful example of the benefits of biotechnology



the need for it
is
rapidly increasing fo
r many reasons;


diabetes often doesn't occur until old age and more people are now
living to old age

it is now also becoming more common in young people

people live longer, and better treatment means many more patients
survive to old age

purifying insuli
n from the pancreas of slaughtered cattle and pigs was
slow and expensive

animal insulin was not as effective as human insulin

some patients were allergic to animal insulin

some patients did not like using a product form slaughtered animals

the

insulin produced by bacteria as a result of genetic engineering is
pure human insulin
.

its production is both quick and relatively cheap

it has none of the problems associated with the use of cattle or pig
insulin.




there are dangers involved with genet
ic engineering since it involves creating
completely new strains of bacteria.



the possibility therefore exists of creating some which might be harmful to
animal or plant life.




biological detergents contain enzymes produced by bacteria.



many

of the stains on clothes are proteins [blood, grass, gravy etc. etc.]



the enzymes [such as proteases} break down and digest proteins



this allows easier removal of the stains.



the enzymes work at relatively low temperatures


they remove stains which would
otherwise need high temperature
washes

this saves energy and money by allowing low temperature washes.

it also helps to get delicate fabrics, which would be damaged by a very
hot wash, properly clean.




an antibiotic is a chemical which prevents the growth
of micro
-
organisms




there are many diseases, each caused by different bacteria



different bacteria are affected by different antibiotics



one antibiotic may only work against certain types of bacteria



this means that a range of different antibiotics is neede
d for the treatment
of bacterial diseases.




immobilisation techniques restrict the movement of enzymes or cells.



this is usually done by attaching them to beads of jelly or other carrier
substances



immobilisation techniques allow continuous flow processing

by effectively
keeping the enzymes or cells separate from the product.



the product formed is exactly the same as it would be without immobilisation



the time & costs of purifying the product by separating it from the enzymes
is greatly reduced since the en
zymes/cells are unable to spread through the
product



the enzyme
/
cell remains inside the fermenter, whilst the end product flows
out



this results in increased productivity and reduced costs compared to batch
processing.



continuous

flow processing usually works out faster, cheaper and more
efficient than batch processing.