Unit4 biotechnology


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Unit4 biotechnology

  2. 2. - DNA is the molecule that stores genetic information. - It is a chain (polymer) of smaller molecules (monomers) called NUCLEOTIDES. - Each nucleotide is formed by a sugar (deoxyribose), a nitrogenous base (A, T, C, G), and phosphoric acid. - There are four different types of nucleotides, depending on the base.
  3. 3. - DNA is a DOUBLE HELIX of two nucleotide chains. - The two chains are linked thanks to the bonds formed between the bases: A is always paired to T we say they are G is always paired to C COMPLEMENTARY
  4. 4. James Watson and Francis Crick discovered the double helix structure of the DNA in 1953, and won the Noble Prize in 1962.
  5. 5. Genetic information is stored in the SEQUENCE OF NUCLEOTIDES of the DNA (that is, their order in the chain)
  6. 6. DNA REPLICATION: making two exact copies of a DNA molecule 1.- The helix uncoils and the two strands separate. 2.- The free nucleotides in the nucleus pair with the nucleotides of each chain, according to the complementary rules (A-T, G-C). 3.- The new nucleotides join to form the new strands. 4.- In the end, two identical molecules of DNA are obtained: each of them has an old strand and a newly-formed strand. That is why we say that DNA replication is semi-conservative.
  7. 7. How is genetic information used in the cell?: GENES AND PROTEINS: TRANSCRIPTION AND TRANSLATION REMEMBER: - Genes are fragments of DNA that have the information needed to produce a protein. Genes are sequences of bases (ATTGCCTAG...) and they form a person's genotype. - Proteins are the molecules that do the different jobs in the cells. They are made of 20 different types of amino-acids joined in chains. Two proteins are different depending on the composition and order of their amino-acids (sequence of amino-acids) They are responsible of a person's phenotype. - So, the sequence of bases of DNA will be used as a template to build proteins (sequence of amino-acids).
  8. 8. Transcription: the genetic information stored in the DNA is copied to a RNA molecule called mRNA (messenger RNA). This goes out of the nucleus into the cytoplasm. RNA is a single-strand molecule of polinucleotides. It has ribose instead of deoxy-ribose, and U instead of T.
  9. 9. Translation: the genetic information that the RNA carries (in the sequence of bases) is read in the cytoplasm by the ribosomes, which use it as a template to synthesise proteins. A group of 3 nucleotides (CODON or TRIPLET) codifies an amino-acid Ala
  10. 10. GENETIC CODE: - A 3 letters (codon) code. - UNIVERSAL: shared by all living beings. - DEGENERATE: one amino-acid is codified by more than one codon (= the genetic code is redundant) - 3 stop codons mark the end of protein synthesis.
  11. 11. MUTATIONS are changes in the DNA: These changes happen RANDOMLY and naturally, although there are some MUTAGENIC AGENTS or MUTAGENS that increase their frequency: - RADIATIONS (X-rays, gamma-rays, UV-rays) - some chemicals like mustard gas and many chemicals in tobacco - pollutants in the environment Mutations in somatic cells cause alterations, diseases (cancer...) but ONLY MUTATIONS IN GERMINAL CELLS (GAMETES) MAY BE TRANSMITTED TO THE NEXT GENERATION (INHERITED)
  12. 12. Most mutations are harmful, or even deletereal for the individuals that carry them. But some may be beneficial and give them an advantage to survive and reproduce. Mutations increase genetic diversity, which allows the EVOLUTION of species.
  13. 13. TYPES OF MUTATIONS: Point mutations (change in a single base): - insertion - deletion - substitution
  14. 14. Silent mutations don't change the sequence of amino-acids in the protein. This is possible thanks to the degeneracy of the genetic code.
  15. 15. AN EXAMPLE OF MUTATION: SICKLE CELL ANAEMIA A mutation in the gene of haemoglobin produces an abnormal protein that makes red blood cells stiff and sickle-shaped instead of flexible and discshaped. This sickle cells can block the bloodflow in the capilaries.
  16. 16. Mutations can also happen with fragments of chromosomes. Or even whole chromosomes or whole sets of chromosomes Humans have 23 pairs of chromosomes, while all the other apes have 24. Human chromosome 2 is thought to have resulted from the fusion of two ancestral chromosomes.
  17. 17. What is Biotechnology? Biotechnology is the use of living organisms or molecules obtained from them to develop products that are useful for the people, the industry or the environment.
  18. 18. RED BIOTECHNOLOGY: Applied to HEALTHCARE e.g. treating diseases, designing organisms to produce antibiotics gene therapy, etc BLUE BIOTECHNOLOGY: And others: BIOINFORMATICS, etc Applied to MARINE and FRESHWATER ORGANISMS e.g. increasing food supplies, WHITE BIOTECHNOLOGY: BIOTECHNOLOGY controlling proliferation, etc Applied to INDUSTRIAL PROCESSES e.g. producing enzymes and other chemicals GREEN BIOTECHNOLOGY: Applied to AGRICULTURE e.g. transgenic plants resistant to pests and diseases, with increased nutritional value, and other improvements
  19. 19. BIOTECHNOLOGY IN HISTORY: - For ten thousand years fermentation has been used to produce wine, beer and bread. - Selective breeding of animals such as horses and dogs has been going on for centuries. - Selective breeding of essential foods such as rice, corn and wheat have created thousands of local varieties with improved yield compared to their wild ancestors.
  20. 20. Nowadays, biotechnology uses GENETIC ENGINEERING techniques to transfer genes from one organism to another, in order to improve its properties or produce useful products. Genetic engineering has some important advantages: - Genetic engineering allows us to transfer only the precise isolated gene we are interested in, and not the whole genome. - Also, it allows us to transfer genes between organisms of different species. The gene that is transferred from one organism to the other is called a TRANSGENE. The organism that are obtained with this technique are GENETICALLY MODIFIED ORGANISMS (GMO), and the DNA that contains fragments of different origins is RECOMBINANT DNA.
  21. 21. Cloning a Gene: isolating a gene and producing many copies of it in another organism. A plasmid from a bacterium can be used to clone a gene of interest from another organism
  22. 22. After cloning it in a host cell, multiple copies of a gene of interest can be harvested. The cloned genes are useful for basic research, and their proteins can be applied to many uses. - Pest resistance in plants. - Cleaning up toxic waste. - Proteins that dissolve blood clots. - Human growth hormone (HGH).
  24. 24. 2.- GENE THERAPY
  25. 25. 3.- BIOSENSORS: Analytical devices that give us information about our organism with a non-invasive procedure.
  26. 26. The enzymatic oxidation of glucose produces hydrogen peroxide, which in turn generates electrons by electrode reaction. The current density is used as a measure of glucose in the sample.
  27. 27. 4.- AGRICULTURE AND FOOD PRODUCTION: Genetic Engineering allows us to introduce one or a few known genes into a plant, giving it the desired qualities that traditionally we would obtain by random crossing.
  28. 28. Through these techniques we can obtain new crops (ie. rice, cotton, corn, soy, tobacco, tomatoes, sugar beet) with new features such as: - plague or herbicide resistances - higher tolerance to adverse conditions (droughts, temperatures, salinity) - faster growth, higher efficiency - new industrial applications: biodegradable plastics, bioplastics – plastics made of vegetables-, edible vaccines; Euro notes are made of transgenic cotton.
  29. 29. Bt corn incorporates a gene of a soil bacterium called Bacillus thuringiensis and so it is able to produce a protein “Bt toxin” that kills Lepidoptera larvae, in particular, European corn borer. Growers use Bt corn as an alternative to spraying insecticides for control of this plague.
  30. 30. Biotechnology may be applied to any of the steps in the food production chain: - improvements in the foods: golden rice (genetically modified to contain betacarotene, a source of vitamin A that may prevent blindness caused by malnutrition) - new products with new scents and additives - enriched foods (in vitamins, fibre...) - detection of pathogens - detection of alimentary frauds
  31. 31. 5.- BIOTECHNOLOGY IN VETERINARY - Transgenic animals are more difficult to develop than plants. - To obtain GM animals, we inject the desired genes in the ovule, so alll the cells in the animal will inherit it. - We can produce drugs (ie. Factor IX in sheep milk) or animal models to study human diseases. .
  32. 32. - We can also clone a whole animal by injecting the nucleus of a cell from an individual in the previously enucleated zygote of another. Dolly the sheep was the first animal that was clonned in this way (1996-2003)
  33. 33. 6.- ENVIRONMENTAL BIOTECHNOLOGY - treatment of waste waters - degrading the hydrocarbons in black tides /oil spills - removal of heavy metals (As, Pb, Hg) from the soil
  34. 34. BIOFUELS - fuels obtained from living beings or organic matter that help reduce the use of fossil fuels - BIODIESEL: from oily seeds. It is used mixed with normal diesel. - BIOETANOL: an alcohol obtained from the fermentation of sugars (sugar cane, sugar beet, corn...) - BIOGAS: mixture of methane and carbon dioxide obtained from the bacterial decomposition of organic wastes.
  36. 36. What Do YOU Think?