Biotechnology
Altering an organism's genetic code
so that it produces desired protein
B. Techniques to Locate and
Identify DNA
1. DNA Extraction
2. Restriction Enzymes- enzymes that cut
DNA at a specific base sequence
Restriction Enzymes
Contributions of Salvador Luria
Early biochemistry work was conducted on organisms with
small genomes like E. coli and viruses that prey upon them
A plate with nutrient agar would
be inoculated with bacteria and
they would be allowed to grow
until they covered the plate
Later, phages were added and they
would attack and kill the bacteria
leaving empty spots on the plate called
plaques
Salvador Luria’s Observation and
Hypothesis
• Luria observed some bacteria that were
unaffected when exposed to phages
• Luria hypothesized that these bacteria had
some type of primitive immune system that
restricted phage growth
• Contributions of Daniel Nathans He realized
because DNA has a negative charge, restriction
fragments could be separated using an electric
current
Bacteria Evolved Restriction Enzymes
In order to reproduce,
viruses must attach to a
host cell
Phage
Viral DNA
Host Cell
Restriction Enzyme
Host Cell DNA
The virus then injects
it’s DNA into the host
cell
How Restriction Enzymes Protect Bacteria
Restriction enzymes bind
with the viral DNA at
specific base sequences
called recognition sites
The viral DNA is cut at specific
sites called restriction sites
which destroys it and protects
the bacteria from infection
Naming Restriction Enzymes
EcoR I
E
BamH I
genus
Echericia
B
genus
Co species
coli
am species
amyloliquefaciens
R
Strain
R
H
Strain
H
I
Order found 1st
I
Order found 1st
Hind III
H
genus
Haemophilous
in species
influenzea
d
d
Strain
III Order found 3rd
Bacillus
3. Gel Electrophoresis- separating cut
DNA fragments by size using an electric
current
4. PCR- Polymerase Chain Reactionallows specific DNA fragments to be
copied millions of times
5. RFLPs- Restriction Fragment
Length Polymorphism
a) Used to identify DNA when a mutation
adds or deletes a restriction site
b) Gel electrophoresis separates the DNA
fragments and mutations are identified by
an abnormal number of fragments
6. VNTRs & STRPs- similar to RFLP
analysis, but uses highly variable, noncoding sequences of DNA
C. Techniques for Inserting DNA
1. Heat Shock Transformation- rapid
temperature fluctuation of cell walls that
pushes DNA into a bacterial cell
2. Microinjection- thin needles
insert DNA into cells
D. Uses of Recombinant DNA
Technology
1) Pharmaceuticals- Humilin, TPA, interferon,
TNF, Artificial hemoglobin, human growth
hormone
2) Agriculture- incide, Flavr-saver tomatoes, frost
resistance, salt resistance, insect resistance,
herbicide resistance, nitrogen fixation
3) Forensics- DNA finger printing
4) Medical- gene therapy
E. Dangers of Genetic Engineering
1. Pathogens- disease causing organisms
2. Eugenics- should we control
or alter our own genome?
3. Stem Cells- growing new human
tissues from cell derived from fertilized
eggs
4. Legal Questions- can/should
we patent life?
5. Genetic Screening- who would get
the results of the tests and how could test
results be used?
6. GMOs- Genetically modified organisms