Transcript GM Food

Product of biotechnology
GM food
Wan Hing Lung(26)
What are GM foods?

The food produced by genetically
modified organisms,which were
produced by the transfer of genes
from one organism to another ,was
called GM food(Genetically Modified
food).
Examples of GM food.
Chymosin
During the production of
cheese,an enzyme from the
rennet is needed.However,it is
expensive to obtain such
enzyme and the quantity was
too low.
However, Microorganisms have
been modified genetically to
yield chymosin that is identical
to the enzyme obtained from
animals.
Today about 90% of the hard
cheese in the UK is made using
chymosin from geneticallymodified microbes.
How to make GM food?
(example:pest resistant GM
plant)
a)A bacterium
produces a toxic
protein which kills
caterpillars and
other pest larvae.
b)The gene coded for
the toxin was
isolated
c)The gene for the
toxin is introduced
into a bacterial
vector which is ring
of DNA which has
been cut open by
enzymes.
d)The vector is put
into another
bacterium.
e)The bacterium
divides
repeatedly,producin
g many
bacteria.Gene in
vector is replicated.
f)The bacteria are
incubated with plant
cells and the vector
will be transferred
from the bacterial
cells to the plant
cells.
g)The plant cells
develop to a plantlet.
h)The plantlet
develops to a plant
that carries the
gene for making the
toxin.
What are the potential benefits of
GM food?
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Increase crop yields
Increase the tolerance of crops to adverse growing
conditions, e.g. drought
Improve the nutrient composition of crops, e.g.
increase the protein content of rice
Provide resistance to crop pests and reduce the use
of pesticides
Improve sensory attributes of food, e.g. flavor,
texture
Improve processing characteristics so as to reduce
wastage and costs
Eliminate allergy-causing properties in some foods
a.Providing resistance to pests

GM corn can
produce a toxin
against insects,thus
reducing the need
for application of
chemical pesticides.
b.Increasing tolerance to poor
environmental conditions

Antifreeze genes
are inserted to
potatoes with the
result that the
potatoes with the
result that the
potatoes can
tolerate cold
temperatures.
c.Improving nutritional content
of crops
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People in third world
countries rely on a
single crop for their
diet.GM rice
contains additional
vitamins and
minerals.This solves
the problem of
malnutrition.
d.Reducing wastage and costs
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GM tomatoes have a
longer shelf-life
e.Increasing crop yields

Larger tomatoes can
be produced.
f.Eliminating allergy-causing
properties in some foods
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A protein in peanuts
causes allergy.GM
peanut has the
protein removed.
Are GM food safe?

World Health Organization (WHO) has
pointed out that GM foods currently
available on the international market have
passed risk assessments and are not likely to
present risks for human health. In addition,
no effects on human health have been shown
as a result of the consumption of such foods
by the general population in the countries
where they have been approved.
Criticisms against GM food
Development of super germs
 disturbing the balance of ecosystems
 Domination of world market for food
products by a few large countries
 Ethical problems

a.Development of super germs
GM food result in
transfer of some
antibiotic-resistant
genes to germs.
As a result,the
germs became
stronger and more
difficult to kill.
b.Disturbing the balance of
ecosystem
If GM organisms
are leased to the
ecosystem,what will
happen?
c.Domination of world market for food
products by a few large countries
Most GM food are produced by
industrialized countries.Thus the
income of farmers in developing
countries may be greatly reduced.
What will happen if GM organisms were
released to the ecosystem?
Will the food chain be changed by the
GM organisms?
d.Ethical problems
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Is it logical to
produce GM
organisms?
Do we have the
right to change the
genotype of other
organisms?
Will these be produced?
Discussion
Today,many environmental groups
oppose the production of GM
foods.Their major concern is the
possible environmental impacts caused
by GM food.Do you think that GM foods
should be banned?
Reference
Scope GM food
 National Centre for Biotechnology
education
 Genetically Modified Food
 Howstuffworks” What are genetically
modified (GM) foods?”
 基因改造食物教材套參考手冊
 改造基因生物
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END