Biotechnology:

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Biotechnology

• How Do We Use What We Know about Life?

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Role of bacteria in technology

• Advantage to using bacteria
• Possess plasmids
• Small extra loops of DNA
• Experience transformation
• Bacteria take up plasmids from surroundings

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Role of bacteria in technology

• Advantage to using bacteria
• Scientists can genetically engineer plasmids by
  inserting gene of interest into bacterial
  plasmid.

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Gene Cloning

• Definition using bacteria to make multiple
  identical copies of a single stretch of DNA.
• Useful in understanding eukaryotic genome.
• Cloning Vector
• Any vehicle that inserts a fragment of foreign
  DNA into the genome of a host cell.
• Example virus or genetically engineered plasmid.
• Used in gene therapy.

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Genetic Engineering

• Definition Ability to precisely manipulate DNA
  sequences from widely different organisms.
• Process requires
• Ability to cut DNA
• To insert foreign DNA segment
• Glue DNA sequences together

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Molecular Scissors

• Restriction enzymes
• Cut DNA at specific places called recognition
  sites.
• Form sticky ends.

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Restriction Sites
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Molecular Paste

• DNA Ligase
• Form bonds between the sugar and phosphate
  backbone of the DNA molecule.
• Restriction enzymes and DNA ligase make possible
  the combination of DNA from different organisms
  into one DNA molecule
• Called recombinant DNA

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Making Recombinant DNA
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How do we know what size DNA fragments we have?

• Agarose gel electrophoresis
• Allows separation of DNA on the basis of size.
• Can visualize DNA to determine exactly how large
  it is.

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Making a DNA library

• Need the following
• A gene of interest
• Restriction enzymes
• Plasmids
• DNA ligase
• Can create a cloning vector using these tools
  which can be inserted in a bacteria
• Allow bacteria to reproduce
• DNA library entire collection of bacterial
  cells which contain cloned gene

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Screening a DNA Library

• Need to find the gene of interest in the bacteria
  or bacterial cells that possess the gene of
  interest.
• Use nucleic acid hybridization to find the gene
  of interest.

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Nucleic Acid Hybridization

• Requires a molecular probe
• Probe is made of a synthetic single-stranded DNA
  whose sequence is complementary to the gene of
  interest.
• Also has a built-in marker so scientists can find
  it.
• When probe binds to denatured gene of interest, a
  hybrid is formed.

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Polymerase Chain Reaction

• Allows scientists to make copies of a small
  sample of DNA.
• Requires
• Primers two synthetic short strands of DNA that
  are complementary to each of the two DNA
  sequences that flank the gene or DNA to be
  copied.
• Heat-resistant DNA polymerase
• Nucleotides

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DNA Sequencing

• Determining the base-by-base order of the
  nucleotides in a stretch of DNA.
• Can help us identify regions of DNA that contain
  genes.

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DNA Sequencing

• Makes possible comparisons of DNA sequences
• between individuals to teach us about our
  susceptibility to disease.
• between species to teach us about how we evolved.
• Also, DNA sequences teach us about the regulation
  of gene expression.

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Human Genome Project (HGP)

• Overall goal
• decipher the full set of genetic instructions in
  human DNA.
• Develop a set of instructions as a research tool
  for scientists.

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Human Genome Project (HGP)

• Several genomes of model organisms have been
  sequenced as a part of the project.

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What We Have Learned From Human Genome

• First lessonHuman DNA consists of 3 billion base
  pairs
• Contain 20,000-25,000 genes
• 2-3 times as many genes as a worm or fruit fly.
• Approximately 3 of DNA contains the information
  to make proteins.

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What We Have Learned From Human Genome

• Second lesson a greater understanding of genes
  themselves.
• Has important implications to understanding human
  biology and what goes wrong in disease states.
• Help us define disease states and predict
  possible candidates who are likely to suffer from
  a disease based on their nucleotide sequences.

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What We Have Learned From Human Genome

• Third lesson lessons about the human family
  both our diversity and evolution.
• Compare base-by-base sequences of DNA
• Any group of individuals have DNA sequences that
  are 99.9 identical regardless or origin or
  ethnicity.
• Points in DNA sequence where the sequences are
  not identical between two or more individuals are
  called single nucleotide polymorphisms (SNPs)

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HPG has Raised Ethical, Social and Legal Issues

• Who owns genetic information?
• Should people be tested for genetic disorders if
  there is no possibility of treatment?

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How Do We Use Biotechnology?

• Gene therapy treatment of a genetic disease by
  alteration of the affected persons genotype, or
  the genotype of the affected cells.

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Stem Cells

• Definition undifferentiated cells in either an
  adult or embryo that can undergo unlimited
  number of cell divisions.
• Are totipotent
• Could be used to produce complex human tissues or
  replacement organs for people suffering from
  disease.

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Designer Drugs

• Biotechnology has made it possible to predict the
  precise shape of molecules.
• Makes it possible to develop drugs for
  therapeutic use.

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DNA in The Courtroom

• Can be use to determine paternity
• Identifying individuals in criminal and civil
  proceedings.
• Use variable number tandem repeats (VNTR) as
  markers.

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DNA in The Courtroom
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Biotechnology on The Farm

• Goal To increase the worlds food production
  while decreasing the costs and environmental
  damage due to insecticide and pesticide use.

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Biotechnology on The Farm

• Scientists have focused efforts on three areas
• Developing crops capable of fending off insect
  pests without the use of insecticides
• Engineering plants with a greater yield that grow
  in a wider ranges of climates
• Make crops that are resistant to herbicides , so
  that fields can be treated for weeds without
  damaging crops
• Opponents wondering if we are disturbing
  ecological balance in the environment

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Can Biotechnology Save The Environment?

• Bioremediation Use of microorganisms to
  decompose toxic pollutants into less harmful
  compounds.

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Risks of Biotechnology

• Two categories of risks
• Risks to human health
• Risks to the environment

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Questioning The Ethics of Biotechnology

• Privacy and ownership of genetic information.
• Argue altering genes is unnatural.
• Breaches fundamental boundaries between species.
• Are scientists interfering with the order of life?

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Where Are We Now?