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12.4. Biotechnology



Biotechnology can be defined as the set of techniques that use living organisms or their components to obtain products, goods and useful services for people. 


The bioremediation (or bioremediation) is any biotechnological process using microorganisms, fungi, plants or enzymes derived therefrom for recovering means altered environment by polluting their natural state.

Bioremediation can have many uses:

  • Use of microorganisms in the elimination of oil slicks, herbicides or pesticides.
  • Wastewater purification and composting.
  • Microbial leaching or bioleaching. In ores with low metal concentration, bacteria such as Thiobacillus ferrooxidans are used to solubilize the metals and precipitate them elsewhere.
  • Bioaccumulation (lichensmosses, etc ...)
  • Pest control.

Microorganisms in industry

The microorganisms are used in different industrial processes:

  • Pharmaceutical industry:
    • Synthesis of antibiotics. Antibiotics are substances produced by fungi and bacteria that kill or prevent other microorganisms from growing. They were discovered when in 1929, Alexander Fleming observed that in a plate in which there was a culture of the bacterium Staphylococcus aureus that had been contaminated by a fungus (Penicillium notattum) these bacteria did not grow.
    • Hormone synthesis. Escherichia coli bacteria are used for the production of insulin.
    • Synthesis of interferon. Interferons are proteins that intervene in the immune system and that can be produced by bacteria at an industrial level.
    • Synthesis of vaccines and antibodies.
    • Synthesis of vitamins, amino acids and enzymes.
      • Vitamins Some vitamins, such as vitamin B12, are produced industrially from the bacteria Pseudomonas and Propioniobacterium.
      • Amino acids. Amino acids such as glutamic acid, lysine, glycine, methionine and alanine, useful in the food industry, are produced by bacteria of the genera Corynebacterium and Brevibacterium.
      • Enzymes. Various fungi and bacteria produce enzymes such as proteases, amylases, renin, etc.
  • Food industry.
  • Energetic industry. Synthesis of bioalcohols, biogas or natural gas and bio-oils.

Genetic engineering

The genetic engineering is the direct manipulation of genes in an organism using biotechnology for modifying genes, delete or duplicate to alter the genetic composition of an organism.

Advances in gene manipulation have made it possible to obtain microorganisms that produce molecules important to humans, such as protein hormones, non-hormonal proteins, vaccines, interferon, and interleukins.

The genetic engineering of microorganisms is based on introducing the gene responsible for the production of a certain molecule that is intended to be obtained, from the donor DNA, into the genetic material of a bacterium, normally plasmids. The bacteria can then produce the molecule. 

The endonuclease restriction enzymes are responsible for breaking the link between nucleotides for the specific site. The donor DNA fragments are joined with the broken plasmids to form recombinant plasmids that contain the donor DNA.

Some important concepts:

  • Recombinant DNA: Recombinant DNA is an artificial DNA molecule created in the laboratory by joining DNA sequences from two different organisms. By introducing this recombinant DNA into an organism, its genetic information is modified and existing traits are altered or new characteristics appear. The production of a protein not present in a given organism and produced from recombinant DNA, are called recombinant proteins .
  • Restriction enzymes: Restriction enzymes (or restriction endonuclease) are enzymes capable of recognizing a specific sequence of nucleotides within a DNA molecule and cutting at that specific point. This cut-off point is called a restriction site or target. The cleavage occurs by hydrolysis of the phosphodiester bond between nucleotides. Next, DNA ligases are the enzymes that will join the ends of DNA fragments generated by restriction endonucleases.
  • Vectors: A gene vector is an agent that transfers genetic information, by some means, from one organism to another, usually a virus or plasmid. In biotechnology, a cloning vector is used to carry recombinant DNA from a donor cell to another recipient cell into which the gene to be transferred is inserted. Then, the host cell is infected with that recombinant vector, obtaining the transgenic cell.
  • PCR or Polymerase Chain Reaction: mechanism by which it is possible to obtain a large number of copies of a gene or DNA fragment.

GMOs, genetically modified organisms

Organisms that have been genetically engineered to modify their genetic material are called “genetically modified organisms”, known by its acronym in English, GMOs. The transgenic organisms are manipulated OMG but whose genes derived from other organism.

Genetically modified organisms have properties that allow them to be useful in many fields:

  • In medicine (use of genetically modified animals as models of human diseases, development of therapies).
  • In the pharmaceutical industry (use of recombinant microorganisms for the synthesis of antibiotics, hormones such as insulin or growth hormone, recombinant vaccines).
  • In the environment (bacteria, cyanobacteria and modified plants capable of eliminating hydrocarbons and pesticides ...).
  • In agriculture (production of biological insecticides through genetically modified bacteria).
  • In agriculture (use of transgenic plants to create resistance to insects, microbial diseases, herbicides, improve the final product).

Gene therapy

The gene therapy is the process whereby the genetic material of affected cells is modified to replace defective genes and correct the damage they cause in the organism. It tries to eliminate the causes of the disease to eliminate or reduce the symptoms it produces.

Questions that have come out in University entrance exams (Selectividad, EBAU, EvAU)

Aragon, July 2020, question 5

5. Answer the following questions: (2 marks)

a) Define bioremediation. Give two examples. (0.8 points)
b) Define restriction enzyme, genetically modified organism (GMO) and gene therapy (1.2 points)

La Rioja, July 2020, question 18

Explain what recombinant DNA is. What is the role of restriction enzymes? What is a PCR? What about a stem cell?

Basque Country, July 2020, question 1B

Genetic Engineering.

a) (0.5 points) Explain what a recombinant DNA is.

b) (1 point) Explain how a gene is cloned and how recombinant DNA is obtained.

c) (1 point) What are restriction enzymes and what role do they have in genetic engineering?


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