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Chapter 13 Lecture- Biotech

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Chapter 13 Lecture- Biotech

  1. 1. Copyright Pearson Prentice Hall Biology Biology
  2. 2. Copyright Pearson Prentice Hall 13-1 Changing the Living World
  3. 3. Copyright Pearson Prentice Hall Selective Breeding Selective Breeding Selective breeding allows only those organisms with desired characteristics to produce the next generation. Nearly all domestic animals and most crop plants have been produced by selective breeding.
  4. 4. Humans use selective breeding to pass desired traits on to the next generation of organisms.
  5. 5. Copyright Pearson Prentice Hall Hybridization Hybridization is the crossing of dissimilar individuals to bring together the best of both organisms. Hybrids, the individuals produced by such crosses, are often hardier than either of the parents.
  6. 6. Inbreeding Inbreeding is the continued breeding of individuals with similar characteristics. Inbreeding helps to ensure that the characteristics that make each breed unique will be preserved. Serious genetic problems can result from excessive inbreeding.
  7. 7. Copyright Pearson Prentice Hall Breeders increase the genetic variation in a population by inducing mutations.
  8. 8. Mutations occur spontaneously, but breeders can increase the mutation rate by using radiation and chemicals. Breeders can often produce a few mutants with desirable characteristics that are not found in the original population.
  9. 9. Copyright Pearson Prentice Hall Increasing Variation Producing New Kinds of Bacteria Introducing mutations has allowed scientists to develop hundreds of useful bacterial strains, including bacteria that can clean up oil spills.
  10. 10. Copyright Pearson Prentice Hall Producing New Kinds of Plants Polyploidy produces new species of plants because the chromosome number changes. Polyploids are often larger and stronger than their diploid relatives.. Polyploidy in animals is usually fatal.
  11. 11. Copyright Pearson Prentice Hall 13-2 Manipulating DNA
  12. 12. Copyright Pearson Prentice Hall Scientists use their knowledge of the structure of DNA and its chemical properties to study and change DNA molecules.
  13. 13. Copyright Pearson Prentice Hall Scientists use different techniques to: extract DNA from cells cut DNA into smaller pieces identify the sequence of bases in a DNA molecule make unlimited copies of DNA
  14. 14. Copyright Pearson Prentice Hall In genetic engineering, biologists make changes in the DNA code of a living organism.
  15. 15. Copyright Pearson Prentice Hall DNA Extraction DNA can be extracted from most cells by a simple chemical procedure. The cells are opened and the DNA is separated from the other cell parts.
  16. 16. Copyright Pearson Prentice Hall The Tools of Molecular Biology Cutting DNA Most DNA molecules are too large to be analyzed, so biologists cut them into smaller fragments using restriction enzymes.
  17. 17. Copyright Pearson Prentice Hall Each restriction enzyme cuts DNA at a specific sequence of nucleotides. Restriction enzyme EcoR I cuts the DNA into fragments Sticky end Recognition sequences DNA sequence
  18. 18. Copyright Pearson Prentice Hall Recognition sequences DNA sequence Restriction enzyme EcoR I cuts the DNA into fragments Sticky end A restriction enzyme will cut a DNA sequence only if it matches the sequence precisely.
  19. 19. In gel electrophoresis, DNA fragments are placed at one end of a porous gel, and an electric voltage is applied to the gel. The negatively-charged DNA molecules move toward the positive end of the gel.
  20. 20. Gel electrophoresis can be used to compare the genomes of different organisms or different individuals. It can also be used to locate and identify one particular gene in an individual's genome.
  21. 21. DNA plus restriction enzyme Mixture of DNA fragments Gel Power source Gel Electrophoresis Longer fragments Shorter frag ments Active art
  22. 22. Copyright Pearson Prentice Hall 1. restriction enzymes cut DNA into fragments. 2. DNA fragments are poured into wells on a gel. DNA plus restriction enzyme Mixture of DNA fragments Gel
  23. 23. Copyright Pearson Prentice Hall The Tools of Molecular Biology 3. An electric voltage moves the DNA fragments across the gel. The smaller the DNA fragment, the faster and farther it will travel. Power source
  24. 24. Copyright Pearson Prentice Hall The Tools of Molecular Biology 4. The pattern of bands can be compared with other samples of DNA. Longer fragments Shorter frag ments
  25. 25. Copyright Pearson Prentice Hall Using the DNA Sequence Knowing the sequence of an organism’s DNA allows researchers to study specific genes, to compare them with the genes of other organisms, and to try to discover the functions of different genes and gene combinations.
  26. 26. Copyright Pearson Prentice Hall Reading the Sequence In DNA sequencing, a complementary DNA strand is made using a small proportion of fluorescently labeled nucleotides.
  27. 27. Copyright Pearson Prentice Hall Using the DNA Sequence DNA Sequencing DNA strand with unknown base sequence DNA fragments synthesized using unknown strand as a template Dye molecules
  28. 28. Copyright Pearson Prentice Hall Each time a labeled nucleotide is added, it stops the process of replication, producing a short color-coded DNA fragment. When the mixture of fragments is separated on a gel, the DNA sequence can be read.
  29. 29. Base sequence as “read” from the order of the dye bands on the gel from bottom to top: T G C A C Electrophoresis gel
  30. 30. Cutting and Pasting Short sequences of DNA can be assembled using DNA synthesizers. “Synthetic” sequences can be joined to “natural” sequences using enzymes that splice DNA together.
  31. 31. Copyright Pearson Prentice Hall These enzymes also make it possible to take a gene from one organism and attach it to the DNA of another organism. DNA molecules that contain genes from more than one organism are sometimes called recombinant DNA.
  32. 32. Copyright Pearson Prentice Hall Making Copies Polymerase chain reaction (PCR) is a technique that allows biologists to make copies of genes. A biologist adds short pieces of DNA that are complementary to portions of the sequence.
  33. 33. DNA heated to separate strands PCR cycles DNA copies 1 2 3 4 5 etc. 1 2 4 8 16 etc. Polymerase Chain Reaction (PCR) DNA polymerase adds complementary strand DNA fragment to be copied
  34. 34. Copyright Pearson Prentice Hall DNA is heated to separate its two strands, then cooled to allow the primers to bind to single-stranded DNA. DNA polymerase starts making copies of the region between the primers.
  35. 35. Copyright Pearson Prentice Hall 13-3 Cell Transformation Recombinant DNA Host Cell DNA Target gene Modified Host Cell DNA
  36. 36. Copyright Pearson Prentice Hall During transformation, a bacteria cell takes in DNA from outside the cell. The foreign DNA becomes inserted in the cell’s own DNA.
  37. 37. Copyright Pearson Prentice Hall Foreign DNA is first joined to a small, circular DNA molecule known as a plasmid. Plasmids are found naturally in some bacteria and have been very useful for DNA transfer.
  38. 38. Copyright Pearson Prentice Hall The plasmid has a genetic marker —a gene that “marks” cells that have successfully incorporated the foreign DNA. Ex. Production of identifiable protein, antibiotic resistance.
  39. 39. Copyright Pearson Prentice Hall Recombinant DNA Gene for human growth hormone Gene for human growth hormone Human Cell Bacteria cell Bacterial chromosome Plasmid Sticky ends DNA recombination Bacteria cell containing gene for human growth hormone DNA insertion Movie
  40. 40. Copyright Pearson Prentice Hall Transformation in Plants In nature, a bacterium exists that produces tumors in plant cells. Researchers can inactivate the tumor- producing gene found in this bacterium and insert a piece of foreign DNA into the plasmid. Recombinant plasmids are used to infect plant cells.
  41. 41. Copyright Pearson Prentice Hall When their cell walls are removed, plant cells in culture will sometimes take up DNA on their own. DNA can also be injected directly into some cells. Cells transformed by either procedure can be cultured to produce adult plants. TRANSFORMATION = taking in foreign DNA
  42. 42. Complete plant generated from transformed cell. Inside plant cell, Agrobacterium inserts part of its DNA into host cell chromosome. Plant cell colonies Transformed bacteria introduce plasmids into plant cells. Agrobacterium tumefaciens Cellular DNA Gene to be transferred Recombinant plasmid Transformation
  43. 43. Transforming Animal Cells Many egg cells are large enough that DNA can be directly injected into the nucleus. Enzymes may help to insert the foreign DNA into the chromosomes of the injected cell. DNA molecules used for transformation of animal and plant cells contain marker genes.
  44. 44. Copyright Pearson Prentice Hall 13–4 Applications of Genetic Engineering
  45. 45. Copyright Pearson Prentice Hall Transgenic Organisms An organism described as transgenic, contains genes from other species.
  46. 46. Copyright Pearson Prentice Hall Genetic engineering has spurred the growth of biotechnology.
  47. 47. Copyright Pearson Prentice Hall Transgenic bacteria can produce large quantities of important substances useful for health and industry, including human proteins: •insulin •growth hormone •clotting factor
  48. 48. Copyright Pearson Prentice Hall Transgenic animals have been used to study genes and to improve the food supply. Mice have been produced with human genes that make their immune systems act similarly to those of humans. This allows scientists to study the effects of diseases on the human immune system.
  49. 49. Copyright Pearson Prentice Hall Researchers are trying to produce transgenic chickens that will be resistant to the bacterial infections that can cause food poisoning.
  50. 50. Copyright Pearson Prentice Hall Transgenic plants are now an important part of our food supply. Many food plants contain a gene that produces a natural insecticide, so plants don’t have to be sprayed with pesticides.
  51. 51. Copyright Pearson Prentice Hall A clone is a member of a population of genetically identical cells produced from a single cell. In 1997, Ian Wilmut cloned a sheep called Dolly. Dolly and Bonnie
  52. 52. Donor Nucleus Fused cell Embryo Egg Cell Foster Mother Cloned Lamb Cloning Dolly
  53. 53. Copyright Pearson Prentice Hall Cloning Cloning Dolly
  54. 54. Copyright Pearson Prentice Hall Cloning Dolly
  55. 55. Copyright Pearson Prentice Hall Cloning Dolly
  56. 56. Copyright Pearson Prentice Hall Cloning Dolly
  57. 57. Copyright Pearson Prentice Hall Cloning Dolly
  58. 58. Copyright Pearson Prentice Hall Cloning Dolly
  59. 59. Copyright Pearson Prentice Hall Researchers hope cloning will enable them to make copies of transgenic animals and help save endangered species. Studies suggest that cloned animals may suffer from a number of genetic defects and health problems.
  60. 60. Copyright Pearson Prentice Hall 13-1 The usual function of selective breeding is to produce organisms that a. are better suited to their natural environment. b. have characteristics useful to humans. c. can compete with other members of the species that are not selected. d. are genetically identical.
  61. 61. Copyright Pearson Prentice Hall 13-1 Crossing a plant that has good disease- resistance with a plant that has a good food- producing capacity is an example of a. inbreeding. b. hybridization. c. polyploidy. d. crossing over.
  62. 62. Copyright Pearson Prentice Hall 13-1 New species of plants that are larger and stronger are a result of a. monoploidy. b. diploidy. c. polyploidy. d. triploidy.
  63. 63. Copyright Pearson Prentice Hall 13-1 The function of inbreeding is to produce organisms that a. are more genetically diverse. b. are much healthier. c. are genetically similar. d. will not have mutations.
  64. 64. Copyright Pearson Prentice Hall 13-1 Increasing variation by inducing mutations is particularly useful with a. animals. b. bacteria. c. plants. d. fungi.
  65. 65. Copyright Pearson Prentice Hall 13-2 Restriction enzymes are used to a. extract DNA. b. cut DNA. c. separate DNA. d. replicate DNA.
  66. 66. Copyright Pearson Prentice Hall 13-2 During gel electrophoresis, the smaller the DNA fragment is, the a. more slowly it moves. b. heavier it is. c. more quickly it moves. d. darker it stains.
  67. 67. Copyright Pearson Prentice Hall 13-2 The DNA polymerase enzyme Kary Mullis found in bacteria living in the hot springs of Yellowstone National Park illustrates a. genetic engineering. b. the importance of biodiversity to biotechnology. c. the polymerase chain reaction. d. selective breeding.
  68. 68. Copyright Pearson Prentice Hall 13-2 A particular restriction enzyme is used to a. cut up DNA in random locations. b. cut DNA at a specific nucleotide sequence. c. extract DNA from cells. d. separate negatively charged DNA molecules.
  69. 69. Copyright Pearson Prentice Hall 13-2 During gel electrophoresis, DNA fragments become separated because a. multiple copies of DNA are made. b. recombinant DNA is formed. c. DNA molecules are negatively charged. d. smaller DNA molecules move faster than larger fragments.
  70. 70. Copyright Pearson Prentice Hall 13-3 Plasmids can be used to transform a. bacteria only. b. plant cells only. c. plant, animal, and bacterial cells. d. animal cells only.
  71. 71. Copyright Pearson Prentice Hall 13-3 An unknowing pioneer in the concept of cell transformation was a. Luther Burbank. b. Frederick Griffith. c. Oswald Avery. d. James Watson.
  72. 72. Copyright Pearson Prentice Hall 13-3 One reason plasmids are useful in cell transformation is that they a. are found in all types of cells. b. prevent gene replication. c. counteract the presence of foreign DNA. d. have genetic markers indicating their presence.
  73. 73. Copyright Pearson Prentice Hall 13-3 A common method of determining whether bacteria have taken in a recombinant plasmid is to a. introduce them into plant cells. b. introduce them into animal cells. c. treat them with an antibiotic. d. mix them with other bacteria that do not have the plasmid.
  74. 74. Copyright Pearson Prentice Hall 13-3 Successful transformation of an animal or a plant cell involves a. the integration of recombinant DNA into the cell’s chromosome. b. changing the cell’s chromosomes into plasmids. c. treating the cell with antibiotics. d. destroying the cell wall in advance.
  75. 75. Copyright Pearson Prentice Hall 13–4 Insulin-dependent diabetes can now be treated with insulin produced through the use of a. transgenic plants. b. transgenic animals. c. transgenic microorganisms. d. transgenic fungi.
  76. 76. Copyright Pearson Prentice Hall 13–4 Transgenic tobacco plants that glow in the dark were produced by transferring the gene for luciferase from a a. clone. b. bacterium. c. firefly. d. jellyfish.
  77. 77. Copyright Pearson Prentice Hall 13–4 The first mammal to be cloned was a a. sheep. b. horse. c. dog. d. cat.
  78. 78. Copyright Pearson Prentice Hall 13–4 In producing a cloned animal, an egg cell is taken from a female and its nucleus is removed. A body cell is taken from a male. The clone from this experiment will a. look just like the female. b. be genetically identical to the male. c. have a mixture of characteristics from both animals. d. resemble neither the male nor the female.
  79. 79. Copyright Pearson Prentice Hall 13–4 Animals produced by cloning have been shown to a. all be perfectly healthy. b. suffer from a number of health problems. c. live longer than uncloned animals. d. be less intelligent than uncloned animals.

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