Biotechnology
Unit 6
I. What is biotechnology?
• Biotechnology is a the use of living systems
and organisms to develop or make useful
products.
• Today we try to use biotechnology to find new
medical cures, to increase agricultural yields,
to find new fuel sources or solutions to
various environmental problems.
• We use DNA tools to modify the DNA of
organisms to produce useful products. These
organisms are called genetically modified
organisms (GMO’s).
• We can genetically modify organisms by:
– altering the DNA of existing genes to modify
proteins coded from the genes
– Adding a foreign gene to an organism – these are
called transgenic organisms
– Deleting or turning off existing genes.
http://www.radiolab.org/story/91607-intelligent-design/ -- biotechnology
http://www.radiolab.org/story/91602-genes-on-the-move/ -- MIT students at 9:15
II. Important Research Methods Used
by Biotechnology
A. DNA Sequencing
• Used to determine the nucleotide sequence of a given
gene or an entire organism.
• During sequencing, DNA molecules are cut into
fragments. Than these fragments are copied many
times. These copied are separated to single-strand
DNA molecules and the complementary nucleotides
are added one at a time while electronic monitors
detect which nucleotide was added at each time.
• This method could be used to study the DNA of entire
organisms, paternity cases, genetic testing,
evolutionary research, etc.
https://www.youtube.com/watch?v=nudG0r9zL2M
B. Restriction Enzymes
• These are special enzymes originally found in
bacteria that cut DNA at certain sequences
(recognition sites).
• Some enzymes cut between the base pairs of the
DNA and create sticky ends, that can be attached
to new parts of a DNA molecule.
• Other enzymes cut across the double helix and
create blunt ends.
• This method can be used to cut “gaps” in a large
DNA molecule and than insert a new gene into
the DNA.
http://highered.mheducation.com/sites/0072437316/st
udent_view0/chapter16/animations.html#
C. Ligation
• The process of reassembling DNA fragments by
using DNA ligase enzyme is called ligation.
• When DNA from different sources (different
organisms) is assembled by this process, we call
it recombinant DNA.
http://www.dnalc.org/view/15487-DNAligation-3D-animation-with-no-audio.html
D. Gel Electrophoresis
• Gel electrophoresis is a method that separates large
molecules (like nucleic acids and proteins) on the
basis of their size, electric charge and other
properties.
• The DNA for this is usually cut into smaller pieces by
restriction enzymes, than injected into a gel. Electric
current is run through the gel and the molecules are
dragged along in the gel by the current.
• Smaller molecules run further than larger ones, than
they are compared to a standard.
• This method is used to identify and separate
segments of DNA molecules for further study,
copying or sequencing, used to purify DNA, to detect
mutations, to identify individuals etc.
http://www.dnalc.org/resources/animations/g
elelectrophoresis.html
E. Polymerase Chain Reaction (PCR)
• This method is used to amplify (copy) segments
of DNA molecules (genes) that scientists are
interested in studying. Within hours PCR can
generate millions of copies of DNA from very
small amounts.
• The copied segments can be used for a wide
range of purposes. For example to insert a gene
into an organism, to sequence the DNA, to be
used for crime scene investigations, etc.
•
•
http://highered.mheducation.com/sites/0072437316/student_view0/chapter16/animations.html
http://www.cnpg.com/video/flatfiles/539/ -- PCR song
III. How Can Biotechnology Benefit Us?
This list is just a short one on how biotechnology
can benefit us today:
• We can insert genes into bacteria to make useful
enzymes and hormones for us. Such as insulin for
diabetics, enzymes to make cheese and other
food products, antibiotics and other drugs.
• Golden rice is genetically modified to provide
vitamin A to people who would have low levels of
this vitamin because of rice centered diet.
• Soy, cotton and other plants are genetically
modified to be herbicide resistant.
• Plants can be genetically modified to be
undigestable or unedible for insects
• Plants can be genetically modified to grow
faster and yield more food for us
• Bacteria or other organisms can be modified to
produce vaccines for us against harmful
pathogens
• Bacteria can be genetically modified to digest
spilled oil or other toxins to clean up the
environment.
• Immunglobulins can be modified to specifically
act against certain cancer cells etc.
IV. What Are The Threats?
• Biotechnology has to be applied carefully and
every new product needs to be tested out
thoroughly before it is introduced into use.
• There are some dangers:
– Superbugs, pathogens may be produced
– Disruptions in the food chains
– We may create undigestable or dangerous chemicals
in crops or livestock
– Ethical issues, like who should know your genetic
makeup, your mutations, should we alter other
organisms