3.5 GMOS

3.5 – Genetic modification and  biotechnology

Lesson 1 – Making a transgenic organism


  • Genetic engineering – Altering the genome of an organism using technology
  • transgenic organism- An organism that has had genes from a different species incorporated into its genome by genetic engineering
  • Enzymes – biological catalysts (eg. restriction enzymes and dna ligases)
  • GMO –  Genettically modified organism. an organism that has been genetically altered  in some way .

A GMO, or Genetically Modified Organism is a species that has had it’s DNA altered using the techniques of genetic engineering.

A classic example is the production of human insulin by bacteria. This bacteria is a GMO that has been achieved by transferring the human insulin gene into the plasmid of an E.Coli bacteria.

Essential enzymes:

  • DNA restriction enzymes – cut the DNA, so that the required gene can be removed.
  • DNA ligases – joint fragments of DNA together, allowing the transferred gene to be joined with the genetic material of a plasmid (this is called annealing, and the cut ends are called ‘sticky ends’ because they include unpaired DNA bases).

Figure: Steps of Gene transfer for creating the GMO ‘human insulin producing E.Coli’

image credit: biology discussions.com

image credit: biology discussions.com


Task: Make a summary handout illustrating the stages in genetic engineering, and emphasising the role of the enzymes. Use another example of genetic engineering from your research, but following the same steps as in recombinant insulin in E. Coli.

Genetically modified organisms are a highly controversial topic not just in Brazil, but worldwide. Claims and risks about GMOs can be divided into environmental, agricultural, and health issues.

1) GMOs and environmental issues:

for the positive

  • Pest resistant crops would allow us to reduce the use pesticides
  • Food products last longer, reducing wastage

but the risks are

  • The toxins made in pest resistant GMO crops will poison non-target species
  • The spread of pest resistant genes to wild plants will create super-weeds
  • Biodiversity could be threatened as ‘escaped genes’ affect wild populations

2) GMOs and health issues

for the positive

  • nutritional value can be improved eg. extra vitamins
  • edible vaccines can be created
  • the allergenic effects of crops could be reduced

but the risks are

  • pest-resistant GMOs could stimulate allergies
  • GMOs may have unexpected long-term effects on human health which have not been adequately tested
  • mutations may cause transferred genes to have unexpected effects.

3) GMOs and agricultural issues:


for the positive

  • crops resistant to cold, drought, salinity can allow crops to grow in previously unsuitable land
  • herbicide resistant genes can allow weeds to be killed easily
  • disease resistance genes can prevent infections and failed crops
  • pest-resistant plants can be developed which resist insect or fungal attacks

but the risks are

  • toxic GMO plants will stimulate resistance to these toxins in pests, and could create new pests
  • patent laws prevent re-sowing so the GMO plants can never become adapted to local conditions

Lesson 2


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image credit: missingfactor.weebly.com

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