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Unit7_MolecularGenetics

Powerpoint explaining DNA, replication and synthesis the proteins and genetic engineering

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Unit7_MolecularGenetics

  1. 1. UNIT7: MOLECULARGENETICS
  2. 2. INDEX 1. DNA 2. Replication 3. The Expression of GeneticInformation 4. The HumanGenome 5. Genetic Engineering 6. Biotechnology
  3. 3. 1. DNA Genes • Are located on chromosomes • Are the basic units of inheritance that carry genetic information • Consist of DNA (deoxyribonucleic acid)
  4. 4. In 1953 Watson and Crick proposed the double helix model of the DNA molecule. Their discovery was based in one X-ray picture taken by Rosalind Franklin. However, only Watson, Crick and Wilkins were awarded with the Nobel prize in 1962, when she had already died because of ovarian cancer. Rosalind Franklin. Picture 51
  5. 5. A molecule of DNA is formed from units called NUCLEOTIDES P nitrogenous Adenine Thymine Guanine Cytosine NUCLEOTIDE
  6. 6. Nucleotides join together through the phosphate building a strand (a chain of nucleotides)
  7. 7. DNA is made up of two chains of nucleotides. Both chains are joined together through the nitrogenous bases. Hydrogen bonds
  8. 8. The link between bases follows the next pattern: A and T are complementary G and C are complementary G-C A-T
  9. 9. The two strands are twisted around each other in the shape of a double helix. It is packed inside the nucleus. Video doble helix structure Watson and Crick: https://www.youtube.com/watch?v=VegLVn_1oCE Rap https://www.youtube.com/watch?v=35FwmiPE9tI
  10. 10. Phase G1 Cell growth (protein synthesis) Phase S Replication of DNA Phase G2 Preparation for cell division Mitosis Cytokinesis
  11. 11. 2. Replication of Genetic Information After mitosis every daughter cell receives an identical copy of the mother cell’s genetic information. For this to happen, the DNA needs to copy itself before mitosis begins (phase S). Replication is the process by which DNA duplicates itself. https://www.youtube.com/watch?v=5qSrmeiWsuc 3DNA Replication Cartoons https://www.youtube.com/watch?v=TNKWgcFPHqw 4DNA replication 3D
  12. 12. Replication must be very precise. Otherwise, mutations could appear. Different enzymes (like DNA-polymerase) perform the replication. Steps 1. The double helix opens up and the two strands separate.
  13. 13. 2. New complementary nucleotides are attached to each of the bases of both strands, forming two new strands. 3. At the end, there are 2 identical copies of DNA. Each one has a strand from the original DNA and a new strand. This is why it is called SEMICONSERVATIVE REPLICATION Page 127 activity 2, 3, 5, 6, 7, 9, 10
  14. 14. http://www.nobelprize.org/educational/medicine/dna_double_helix/dnahelix.html http://www.learningliftoff.com/high-school-science-dna-replication/#.VtxuWPnhDIU Games:
  15. 15. 3. The Expression of Genetic Information A. Proteins Proteins are made up of molecules called amino acids. There are 20 amino acids which make up all proteins. Proteins have structural and physiological functions and they are the molecules responsible for the characteristics of the body. A gene is a piece of DNA that contains the information to synthesize a specific protein.
  16. 16. B. RNA (ribonucleic acid) It is made up of nucleotides, but instead of thymine there is Uracil. Types Messenger RNA (mRNA) Copy of the information that is in a specific part of the DNA Ribosomal RNA (rRNA) Ribosomes are made up of RNA Transfer RNA (tRNA) It transports the amino acids to the ribosomes.
  17. 17. This process is performed in two stages:  Transcription (It takes place inside the nucleus) DNA cannot leave the nucleus. The specific piece of information needed is copied onto another molecule: Messenger RNA Stages The double helix of DNA opens up. Only one DNA strand is copied. A RNA strand is produced. The mRNA leaves the nucleus and arrives to the cytoplasm.
  18. 18. The double helix of DNA opens up. Only one DNA strand is copied. RNA polymerase synthetizes the RNA reading 3’ 5’ and creates the new RNA always 5’3’
  19. 19. T - A - C - G - G - C - T - A - C - A - T - G Example of transcription: DNA 3’ 5’ Activity: Write the corresponding RNA sequence T-A-C-T-T-T-G-G-C-G-A-T-A-C-A A-T-G-A-A-A-C-C-G-C-T-A-T-G-T 3’ 5’ 5’ 3’ TEMPLATE DNA 3’ mRNA A-U-G-A-A-A-C-C-G-C-U-A-U-G-U 5’ Transcription (by the RNA polymerase) A - U - G - C - C - G - A - U - G - U - A - CmRNA 5’ 3’
  20. 20. mRNA leaves the nucleus and arrives to the cytoplasm.
  21. 21.  Translation (It takes place in the cytoplasm, in the ribosomes) The ribosome translates the information carried on the mRNA into a chain of amino acids (protein). 1. mRNA positions itself on a ribosome, starting with its 5’ side . Stages: 5’
  22. 22. 2. tRNA transports free-floating amino acids in the cytoplasm to the ribosome, in the order indicated by the mRNA. It reads the nitrogenous bases in groups of three (codons). 3. Each tRNA is specific to an amino acid. 4. The ribosome moves along the mRNA and joins amino acids together in the appropiate order.
  23. 23. Each amino acid is coded by one or more codons. https://www.youtube.com/watch?v=gG7uCskUOrA 5 From DNA to Protein
  24. 24. It is the relationship between the sequence of nitrogenous bases in DNA and the amino acids in the corresponding protein. Characteristics • It is universal • Every living being uses the same mechanism. • The ribosomes can read every mRNA, although it does not belong to this cell. • The same amino acid can be coded by more than one codon. • All proteins start with Metionine, this means every specific mRNA has a starting point which is AUG. • There are some codons which code for “stop”. Activities 11-20 (all) page 131
  25. 25. Write the sequence of the protein synthesized from the next DNA: T-A-C-C-C-T-C-G-G-G-C-A-T-A-A-T-A-G-A-T-T A-T-G-G-G-A-G-C-C-C-G-T-A-T-T-A-T-C-T-A-A 3’ 3’5’ 5’ 1st step: transcription  mRNA A-U-G-G-G-A-G-C-C-C-G-U-A-U-U-A-U-C-U-A-A 5’ 3’ 2nd step: translation protein Met-Gly-Ala-Arg-Ile-Ile
  26. 26. 4. The Human Genome The genome is the organism’s complete set of genes. In order to know someone’s genome we have to know: The whole sequence of nitrogenous bases in DNA Location and function of all the genes Relationship between genes In 2003 the sequence of nucleotides in the human genome was located.
  27. 27. • Diagnosis of genetic disease • Gene therapy (modify genes) • Medicines which can be personalised Applications of mapping the human genome
  28. 28. 5. Genetic Engineering It consists of techniques to manipulate genetic material in order to change an organism’s traits. General technique 1. Location of the gene. 2. Isolation of the gene using restriction enzymes, which cut the DNA in specific places.
  29. 29. 3. Introduction of the gene in a vector (bacterium or virus) to transport it. Vector’s DNA + the gene = RECOMBINANT DNA 4. Insertion of the recombinant DNA into a cell in order to be expressed.
  30. 30. Vector: bacterium Vector: virus
  31. 31. Uses of genetic ingeneering Biological research Researching diseases Police investigations Suspects and victims of crimes Paternity tests Historical and archaeological studies
  32. 32. Gel electrophoresis Suspects and victims of crimes
  33. 33. Risks of genetic engineering • Modified organisms could spread and reach the nature and human beings • Seed control by multinationals (patents) • Possible allergies to new genes
  34. 34. 6. Biotechnology It is the technology which uses living beings to create improved products. Making bread, dairy products, alcoholic drinks Making vaccines and antibiotics Treating rubbish or polluted water
  35. 35. A. Agriculture and farming  Cloning: obtaining genetically identical organisms Dolly was the first mammal to be cloned(1996) https://www.youtube.com/watch?v=-Qry1gYYDCA Dolly the Sheep
  36. 36.  Genetically modified organisms:organism (animal, plant…) which has a gene from another organism so that it can express a new trait. Bt gene is a gene belonging to a bacteria which produces resistance to some insects. It the plant carries it it cannot be eaten by insects.
  37. 37. B. Biomedical Uses  Production of insuline, antibiotics, vitamins… https://www.youtube.com/watch?v=_ob1c-n_oNY&list=PL4473936D327B7C69 Genetic Engineering 7 Wonders of the Microbes
  38. 38.  prevention of genetic diseases  substitution of defective genes before they are transmitted to the gametes.  gene therapy  curing genetic diseases, like cystic fibrosis
  39. 39. Glossary Recombinant DNA Plasmid Restriction enzyme Vector DNA polymerase Page 137, activities 21, 24, 25, 28, 29 Page 138 activities 1, 3, 4, 5

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