Lesson 20: Benefits of Transgenic Organisms

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Dec 11, 2012 (4 years and 4 months ago)

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Lesson 20: Benefits of Transgenic Organisms (3.3.2)


Many scientists and researchers believe that recombinant technology holds great potential
for improvements in agricultural products. There have already been many successes with
the technology. Accord
ing to scientific reports, 95% of our vegetables are genetically
altered and records on animal products from countries around the world have not been
verified.


A ring of DNA called a
plasmid
is removed from a bacterial cell. Restriction enzymes
are used
to cut a segment of the DNA out of the ring.

A segment of DNA called a
gene
,
for example, the human insulin gene is cut out (removed) from a specific sequence of
DNA that code for a specific gene. The insulin gene is inserted into the bacterial plasmid.
T
he result of inserting the gene into the bacterial plasmid is called
recombinant DNA.

The plasmid is then placed back into the bacterial cell and allowed to reproduce.

Bacterial cells carry on binary fission and therefore produce numerous copies of the
in
sulin gene each time the bacterium divides.

The value of these technologies is great for improving the health of individuals and save
lives. Biotechnologies or genetic engineering can be used to make insulin, growth
hormone replace abnormal genes during ge
ne therapy.



TRANSGENIC ORGANISMS


A
transgenic organism

is a genetically modified organism (GMO) that has genes from a
different species.
There are many questions about the possible long term effects of these
genetic technologies. One concern is that ge
netically modified foods may be detrimental
to human health.
Genetically engineered
foods may cause unexpected allergic reactions
in people, since proteins not naturally found in the product have been inserted. Without
labeling, a person will allergies m
ay find it difficult to avoid a known food allergen if
part of the food causing the allergy is genetically added into another food product. In
many European and Asian countries, modified foods most be labeled as such, but in the
United States, the FDA has

not yet required consumer information labeling.


Genetically modified crops could pose some threat to the environment. Since herbicide
-
tolerant crop plants do not die when exposed to the weed
-
killing chemicals, some crops
might be sprayed more heavily to

ensure greater weed control. Some studies have
indicated that the destruction of plant life naturally surrounding the crops reduces the
habitats and food supplies o
f birds and beneficial insects.


These modified crops and animals allow farms to produce h
igher quality and more
bountiful products, which in turn give the farmers a greater earning potential. For
centuries, traditional methods of plant hybridization have been widely used to improve
the genetic characteristics of various agricultural products.

Recombinant technology

takes this to an improved level by allowing scientists to transfer specific genetic material
in a very precise and controlled manner and in a shorter period of time than traditional
methods. For example, in plant crops the charact
eristics of pest resistance and improved
product quality are highly desirable.





CLONING


Cloning

is the creation of genetically identical organisms
.
The
process includes removing the nucleus of the recipient cell and
replacing it with the nucleus of

the donor cell, and then the altered
cell is implanted into the host organism.

The cloning of Dolly the
sheep from a somatic cell of an adult sheep created great debate
about the possibility of cloning humans. The possible benefits of
human cloning incl
ude allowing a childless couple to have a
child, creating tissues for transplantation that would not be
rejected by their host and using genetically altered cells to treat
people with Alzheimer’s or Parkinson’s, both diseases caused by
the death of specifi
c cells within the brain. Another application is
to create therapeutic proteins, like




OTHER MODIFIED ORGANISMS


These modified crops and animals allow farms to produce higher quality and more
bountiful products, which in turn give the farmers a greate
r earning potential. For
centuries, traditional methods of plant hybridization have been widely used to improve
the genetic characteristics of various agricultural products. Recombinant technology
takes this to an improved level by allowing scientists to

transfer specific genetic material
in a very precise and controlled manner and in a shorter period of time than traditional
methods. For example, in plant crops the characteristics of pest resistance and improved
product quality are highly desirable.


Re
combinant technology has already resulted in improved strains of corn, soybeans and
cotton. The desirable genes inserted into the plant’s DNA enable crops to resist certain
insects or tolerate herbicides used to kill weeds. These improvements also enable

farmers
to reduce the use of chemicals, which reduces costs for the farmers, as well as helping to
reduce environmental damage and runoff pollution. Rot
-
resistant tomatoes have been
made possible by agricultural biotechnology. This improved variety allo
ws grocery
stores to offer naturally vine
-
ripened tomatoes instead of tomatoes that were picked green
and artificially ripened on their way to the store.


Some improved products show promise for global impact on the problem of malnutrition.
Researchers wo
rking in cooperation with the International Rice Research Institute have
used
genetic engineering
to develop an improved variety of rice. This hybrid “golden
rice” has been designed to overcome Vitamin A deficiency and to combat iron
-
deficiency
anemia. A

diet containing this improved rice could prevent blindness in millions of
children in Third World countries. Another product in development is a variety of rice
that will grow in the 33 million acres of land in China that have salty soil.


The term,
gene
tic pollution or uncontrolled hybridization
, is used to describe when, in
nature, a genetically modified and non
-
genetically modified plant cross pollinate via by
wind, birds and insects. Also, farmers who want to grow non
-
genetically modified crops
may h
ave a hard time avoiding genetic pollution if their farms are located near fields with
genetically modified plants.


Lesson 20 Review: Benefits of Transgenic Organisms (3.3.2)


A. Define the following terms.


plasmid



cloning


genetically modified or
ganism
(GMO)


transgenic organism

recombinant DNA

uncontrolled hybridization










B. Choose the best answer


1. What is a circular piece of DNA used to clone a desired gene?

A.

plasmid






C. GMO

B.

DNA fingerprint




D. protein injections


2. Wha
t technologies are used to genetically modified organisms?

A.

plasmid






C. biotechnology

B.

DNA fingerprinting




D. restriction analysis


3. Which organism has been genetically modified?

A.

bacterium with an inserted insulin gene

C. “Dolly”

B.

extremely large gr
apefruit



D. small blueberries


4. Which is a benefit of genetically modified organisms that is currently used?

A.

to make natural human insulin



C. to make corn grow taller

B.

to restore cell damaged by UV rays


D. to test man’s ability to alter nature


C. C
omplete the following exercises

1
. Give an example of an advance in biotechnology that you have heard about in the news
or



read about in this chapter. Explain the benefits of the application of biotechnology
.