Recombinant DNA in Bacteria by dffhrtcv3


									Recombinant DNA in Bacteria

             Restriction Enzymes,
                Cloning DNA,
              Genetic Libraries,
And Useful Products Created By Microorganisms
• Plasmids- a small, circular DNA molecule
  separate from the much larger bacterial
• Plasmids are
  double stranded
           Plasmids (cont.)
• Plasmids can replicate, just like normal
• When plasmids replicate, one copy can be
  passed from one bacteria cell to another
• When Plasmids are shared, important
  information, such as an immunity to
  antibiotics, can be passed from a bacteria
  to any other species of bacteria
  Plasmids Can Help Humans
• Scientists can use plasmids to move
  pieces of DNA into bacteria
• These pieces of DNA can instruct bacteria
  to make important substances for humans,
  such as insulin
    Putting DNA into Plasmids
• To place DNA in the plasmids, a plasmid
  is first removed from the bacteria cell
• Next, a desired gene from any kind of cell,
  is inserted into the plasmid
• This creates a recombinant plasmid, or a
  plasmid that contains original and new
• The recombinant plasmid is placed back
  into the bacteria cell, which copies it in a
  process called DNA Cloning
Putting DNA into Plasmids (cont.)
        Restriction Enzymes
• Restriction Enzymes- Enzymes that are used to
  cut DNA
• Restriction Enzymes chop DNA into small pieces
• Restriction Enzymes are found in bacteria,
  where they are used to chop up foreign DNA
• Restriction Enzymes work by finding specific
  nucleotide segments and cutting the sugar
  phosphate backbone at certain places within
  those segments
   Restriction Enzymes (cont.)
• Restriction Enzymes usually make
  staggered cuts
• These staggered cuts leave single
  stranded areas called Sticky Ends, since
  they will bind to any complimentary
• An enzyme called DNA Ligase attaches
  the DNA fragments together
Cutting and Pasting DNA
   Cloning Recombinant DNA
• Biologists can place recombinant DNA in
  bacteria cells which can use the DNA to
  make large quantities of proteins that are
  useful to humans
• Making enough DNA to be useful takes
  several steps
    Libraries of Cloned Genes
• Genomic Library- a complete collection of
  cloned DNA fragments from an organism
• The procedure of cloning DNA creates
  many different clones, each containing a
  different portion of the source DNA
• The different recombinant plasmids
  contain the entire genome of the organism
  from which the DNA was derived
  Identifying Specific Genes With
• One way to find a specific gene is to use a
  radioactive probe, that is complementary
  to a piece of DNA with a known genotype
• A biologist can use nucleotides labeled
  with a radioactive isotope to build a
  complementary single strand of DNA
• The biologist uses chemicals or heat to
  separate the two strands, and the
  radioactive probe is mixed in
  Identifying Specific Genes With
            Probes (cont.)
• Next, the probe tags the correct DNA
  portion by pairing with the complementary
• This way, the biologists can tell which
  bacteria cells contain the gene, and they
  allow those bacteria cells to multiply,
  producing the genes in large amounts
  Useful Products from Genetically
    Engineered Microorganisms
• Bacteria can be given DNA to produce
  chemicals to clean up toxic waste sights
• Bacteria can be used to mass produce useful
• Bacteria can be used to make human insulin
• It is also being used to create vaccines. Genes
  from viruses can be cloned in cells, which allows
  the cells to create large amounts of viral protein,
  which can be used to make the vaccines.

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