Chapter 16.4- Use of recombinant DNA technology
Genetic modification
The genetic make- up of organisms can be changed by transferring genes between individuals of the
same species of between organisms of different species. These modifications can benefit humans in
many ways, some of these are:
Increasing the yield from animals or plant crops
Improving the nutrient content of food
Increasing resistance to disease and pests
Making crop plants tolerant to herbicides
Developing tolerance to environmental conditions (e.g. extremes of temperature and
drought)
Making vaccines
Producing medicines for treating disease
Examples of genetically modified microorganisms
There are three main groups of substances produced using genetically modified bacteria:
Antibiotics – These are produced naturally by the bacteria. Genetic engineering has not
significantly improved quality of antibiotics, it has created bacteria that produce the
antibiotics in greater quantities and at faster rates.
Hormones – more than 2 million diabetics need insulin daily. In the past, insulin from cows
or pigs was used but it could stimulate side-effects because of the immune system’s reaction
to it. Genetic engineering has seen bacteria produced that have the gene to produce human
insulin – this has no adverse side effects on the patient. This method does not need animals
to be killed and also eliminates the need to modify the insulin before it is injected. Other
hormones produced using this method include human growth hormone, cortisone and the
sex hormones, testosterone and oestrogen.
Enzymes – lots of enzymes used in the food industry are manufactured by genetically
modified bacteria. These include amylases (used to break down starch during the production
of beer), lipases (used to improve the flavour of cheeses) and proteases (used to make meet
more tender)
Examples of genetically modified plants
Genetically modified tomatoes – these are developed by insertion of a gene. This gene has a
base sequence complementary to that of the gene producing the enzyme that causes
tomatoes to soften. The mRNA transcribed from this inserted gene is complementary to the
mRNA of the original gene. Therefore, the two combine to form a double strand – this
prevents the mRNA of the original gene from being translated. This means the softening
enzyme is not produced. This allows the tomatoes to develop flavour without the problems
with harvesting, storing and transporting the softer fruit.
Herbicide- resistant crops – These have a gene introduced that makes them resistant to a
specific herbicide. The weeds that are competing with the crop for water, light and minerals
are killed, but the crop plant is unharmed.
Disease- resistant crops – These have genes introduced that give resistance to specific
diseases. GM rice, for example can withstand infection from a particular virus.
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Genetic modification
The genetic make- up of organisms can be changed by transferring genes between individuals of the
same species of between organisms of different species. These modifications can benefit humans in
many ways, some of these are:
Increasing the yield from animals or plant crops
Improving the nutrient content of food
Increasing resistance to disease and pests
Making crop plants tolerant to herbicides
Developing tolerance to environmental conditions (e.g. extremes of temperature and
drought)
Making vaccines
Producing medicines for treating disease
Examples of genetically modified microorganisms
There are three main groups of substances produced using genetically modified bacteria:
Antibiotics – These are produced naturally by the bacteria. Genetic engineering has not
significantly improved quality of antibiotics, it has created bacteria that produce the
antibiotics in greater quantities and at faster rates.
Hormones – more than 2 million diabetics need insulin daily. In the past, insulin from cows
or pigs was used but it could stimulate side-effects because of the immune system’s reaction
to it. Genetic engineering has seen bacteria produced that have the gene to produce human
insulin – this has no adverse side effects on the patient. This method does not need animals
to be killed and also eliminates the need to modify the insulin before it is injected. Other
hormones produced using this method include human growth hormone, cortisone and the
sex hormones, testosterone and oestrogen.
Enzymes – lots of enzymes used in the food industry are manufactured by genetically
modified bacteria. These include amylases (used to break down starch during the production
of beer), lipases (used to improve the flavour of cheeses) and proteases (used to make meet
more tender)
Examples of genetically modified plants
Genetically modified tomatoes – these are developed by insertion of a gene. This gene has a
base sequence complementary to that of the gene producing the enzyme that causes
tomatoes to soften. The mRNA transcribed from this inserted gene is complementary to the
mRNA of the original gene. Therefore, the two combine to form a double strand – this
prevents the mRNA of the original gene from being translated. This means the softening
enzyme is not produced. This allows the tomatoes to develop flavour without the problems
with harvesting, storing and transporting the softer fruit.
Herbicide- resistant crops – These have a gene introduced that makes them resistant to a
specific herbicide. The weeds that are competing with the crop for water, light and minerals
are killed, but the crop plant is unharmed.
Disease- resistant crops – These have genes introduced that give resistance to specific
diseases. GM rice, for example can withstand infection from a particular virus.
Page 1 of 4
