Agriculture: Genetically Modified Organisms

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Agriculture: Genetically Modified Organisms
2013-01-20 14:23:55

Advanced Higher Biology - Unit One - Agriculture: Genetically Modified Organisms
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  1. What effect does Bovine Somatotrophin have on cows?
    It makes them produce more milk (~10%)
  2. What are the steps involved in producing BST using genetically engineered bacteria?
    • Identify the section of DNA that contains the gene of interest (eg gene encoding BST) and extract it from the source chromosome
    • Remove the gene that codes for BST (using restriction enzymes)
    • Extract some bacteria DNA from a bacteria cell
    • Put the gene that codes for BST into the bacterial plasmid (Cut open bacterial plasmid with same restriction enzyme to create 'sticky ends' and use ligase enzymes to seal plasmid)
    • Put the bacterial DNA with the BST gene into bacteria
    • Bacteria replicate
    • BST is made by the bactera and this is collected by scientists
    • BST is given to the farmers who inject the cows or add it to their food
  3. Why do humans produce genetically modified plants?
    • Bigger yield
    • Disease resistance
    • Saline tolerant
    • Pest resistance
    • Nutritionally improved
  4. What type of bacteria is commonly used in the production of transgenic plants?
  5. What property does Agrobacterium have that makes it suitable to produce transgenic plants?
    It has a tumor inducing (Ti) plasmid.  This plasmid is injected naturally into plant cells to make them reproduce their cells and replicate the Ti plasmid (like a tumor).
  6. How are transgenic plants made?
    • The gene of interest is identified and removed from the DNA of the organism using restriction enzymes
    • The Ti plasmid is cut open using restriction enzymes
    • The gene of interest and an antibiotic resistance gene are put into the Ti plasmid (which is sealed using ligase enzymes)
    • The Ti plasmid is then inserted into the bacteria
    • Bacteria with altered Ti plasmids is put in solution with plant protoplasts OR placed on plant material eg plant embryo
    • Ti plasmid will infect the plant and introduce the desired gene into the plant cell causing tumor formation
    • The plant cells are grown on a medium with nutrients and an antibiotic (the same antibiotic that the resistance gene was introduced into the Ti plasmid)
    • The antibiotic resistance gene is attached to the gene of interest.  If the plant has not taken up the gene of interest then it will not have antibiotic resistance and therefore the antibiotic in the growth medium will kill it.  The ones who survive contain the gene of interest.