This unit focused on biotechnology, which is the use and
manipulation of living things and their parts for human benefit. There
are 4 main applications of biotech: industrial and environmental,
agricultural, medical/ pharmaceutical, and diagnostic research. In the
industrial and environmental field, there is fermentation as well as biofuels
(using cellulase to break down cellulose into simple sugars as well as
fermentation to produce alcohol for the fuel). Medical and
pharmaceutical biotechnology includes gene therapy. Gene therapy is inserting a copy of a
healthy gene into a person who has a defective copy of that gene. An
example of agricultural biotechnology is classical breeding, where
individuals with a certain desired trait are bred several times. GMO, or
transgenic organisms, have had recombinant DNA inserted into them. I
felt that I understood this overview of biotechnology fairly well. There
are also certain ethical questions that are asked of the field of
biotechnology, called bioethical questions. Bioethics is the study of
decision-making as it applies to certain advances in biology and
medicine.
One technology in the field of biotech is recombinant DNA (rDNA). It is
taking DNA from one organism and inserting it into another. The first
step in this is to identify the gene of interest and the location and
the sequence. Restriction enzymes are very specific enzymes which cut
DNA whenever they read a specific sequence. They make a jagged cut and
create two "sticky ends" that can bond with other DNA. Plasmids, which
are circular DNA in bacteria, are naturally resistant to a certain
antibiotic. I felt that this topic was one of my strengths, especially
after doing the Recombinant DNA Lab,
where we modeled inserting the insulin gene into a plasmid that was
resistant to tetracycline, and only the bacteria with the plasmid would
survive.
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Model of recombinant plasmid |
Another technology of biotech is PCR (Polymerase Chain Reaction), which
is a procedure that creates millions of copies of a sequence of DNA so
that that sequence can be analyzed. The DNA is denatured with heat,
primers are annealed to the single-stranded DNA above and below the
gene, DNA Polymerase are extended, and the process is repeated. Gel
electrophoresis uses electricity to separate DNA fragments based on
size, since the larger fragments travel more slowly than the smaller
fragments.
In the pGLO Lab
,
we added a plasmid which contained GFP (Glowing Fluorescent Protein) to
E.coli. There were 4 plates: -pGLO LB, -pGLO LB/amp, +pGLO LB/amp, and
+pGLO amp/ara. The bacteria on the -pGLO plate formed a carpet of
colonies. The -pGLO LB/amp plate had no growth. The +pGLO LB/amp plate
had roughly 130 colonies, and the +pGLO LB/amp/ara had 150 colonies and
glowed green under UV light. This lab helped me understand the process
We also did the Candy Electrophoresis Lab,
where we put four reference dyes (Blue 1, Red 40, Yellow 6, Yellow 5)
into four wells. Then we extracted dyes off of candies, such as purple
skittles, blue m&m's, red skittles...etc and inserted them into
remaining wells. We were able to compare the size of the fragments and
identify if any of the reference dyes were present in the candies. From
this lab, I was able to better understand how gel electrophoresis works
and how to analyze the results.
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Candy Electrophoresis Lab |
I want to learn more about gene therapy and the advances in this
technology that are being made today that are getting us closer to the
"GATTACA" world. I also wonder about the ethical questions that go along
with so many of these advances in gene therapy.
This year, one of my new year's goals was to
actively study for tests in biology. And so far, I have done exactly that. I have studies a few weeks ahead of time, made note cards, and I studied what I had difficulty with first. This has really hepled me prepare for this test, and I will continue doing so!
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