Answers to Chapter 1 and 2 Questions
Chapter 1
2.
The difference between molecular biotechnology and traditional biotechnology
comes with the fact that molecular biotechnology requires a knowledge of genes and the
ability to manipulate genes to produce useful goods and services from living organisms.
Molecular biotechnology only truly became possible when techniques for recombinant
DNA technology became available. Prior to that biotransformation was tedious and
difficult but with the dawn of recombinant technologies genetic engineering became
possible and a new age of molecular biotechnology was born. In molecular biotechnology
biotransformation has become the focus.
5.
The work by Cohen and Boyer was extremely relevant because it led to the
establishment of true molecular biotechnology by paving the way for recombinant DNA
technology. Cohen realized that it was possible to introduce genes from one organism into
another. It was this idea that has made it possible to produce human insulin via E. Coli
bacterial hosts. They had developed a method for cloning genes and their success was
readily observable in the tremendous financial gains of their molecular biotechnology
corporation.
6.
Recombinant DNA technologies enabled the production of human insulin because
they made it possible for scientists to synthesize the necessary strands of DNA to produce
insulin, to insert these strands into the DNA of plasmids and finally to inject the plasmids
into the bacterial host E. Coli where the plasmids are maintained. The recombinant DNA
codes for the peptide chains of human insulin and after some purification and modification
the product can be administered to individuals with diabetes that may be allergic to the
alternatively available pig insulin.
10.
The first article that I chose was entitled “Novel Blood Treatment Lures Athletes to
Germany.” It was about a new procedure that was developed by a German doctor, Peter
Wehling. First the doctor takes blood. Next it is incubated and centrifuged to encourage
the production of proteins that fight inflammation and stimulate cell growth. Finally, the
cells are injected into the injured site. The rest of the article spoke about how successful
the treatment has been and other athletes that have sought out the treatment. I am amused
by the idea of manipulating cells to produce compounds that will be conducive to speedy
recovery. It is also interesting that the article mentions that the treatment seems to have
been effective in rejuvenating an aging Kobe Bryant. It is exciting to think that long term
maladies such as bad backs or weak ankles may be a thing of the past as biomedicine
becomes more popular. Perhaps we will see the return of Brett Favre?
http://www.nytimes.com/2012/07/11/sports/athletes-with-chronic-pain-turn-to-novelblood-treatment.html?_r=1&ref=biotechnology
The second article that I read in the biotechnology section was entitled “ Craig
Venter’s Bugs Might Save the World.” This article was about Craig Venter and his ideas for
the creation of artificial life. Venter is experimenting with the possibility of creating an
organism entirely from synthetic DNA. Venter claims that using this technology we could
design functional organisms whose lives would be dedicated to whatever we designed
them for. This possibility is extraordinarily exciting because organisms would naturally
reproduce and produce even more factories. The rest of the article goes into more specific
detail about some of the practical applications of the bugs including medicine, fuel, food,
and pollution. I think that this is a really interesting idea and I agree with Venter that this
is likely one major direction that science will move towards in the future. I am intrigued by
the possibilities that this technology may open up. Honestly, this is something that I would
enjoy researching.
http://www.nytimes.com/2012/06/03/magazine/craig-venters-bugs-might-save-theworld.html?ref=biotechnology
The third article that I read was entitled “Pay Only for Drugs That Help You.” The
article was discussing the fact that consumers pay for drugs that fail to produce results and
that this waste is the reason that we are currently spending far more annually on
healthcare than any other country (2.6 trillion/year). The “pay-for-response” model would
make it so that pharmaceutical companies only received compensation for their drugs if the
doctor could confirm that the drug had done what it is intended to do. Proponents of the
model hope that this would encourage pharmaceutical companies to do more research into
the effectiveness of their drug on different portions of the population. I do not agree with
this proposal. I am all for trying to cut back on waste within healthcare but I do not think
that this is an effective way to do it. Pharmaceutical companies would suffer financially
which would inevitably just necessitate higher prices on drugs that do work.
http://www.nytimes.com/2012/03/07/opinion/pay-only-for-drugs-that-helpyou.html?ref=biotechnology
Chapter 2
1.
In DNA replication each pre-existing strand of DNA acts as a template for the
formation of a new, complementary strand. The phosphate group of each new nucleotide is
joined to the three prime hydroxyl group of the previous nucleotide. Each nucleotide is
paired complementarily, A-T;C-G. In eukaryotes the fact that there are multiple origins of
replication as well as the formation of okazaki fragments due to the limitations of DNA
polymerase necessitates the presence of proteins to join (ligate) the strands. In addition
telomerase is needed to add telomeres to the end of each chromosome to protect the DNA.
The DNA is unwound by helicase and DNA polymerase comes in to bind the strands. The
polymerase adds nucleotides in a three prime to five prime direction to synthesize the new
complementary strand. Binding proteins help to relieve the mechanical stress created by
the unwinding of the helical DNA strand. Other transcription factors assist in the process.
2.
DNA and RNA differ in three important ways. First of all the sugar backbone of the
bases is different. In DNA the sugar is deoxyribose and in RNA it is ribose. Functionally
DNA is missing the O substituent on the 2 carbon of the sugar ring. The second major
difference comes with the fact that RNA is generally single stranded whereas DNA naturally
assumes a complementary double helical structure. The third major difference comes with
the specific bases present in each material. RNA has uracil in place of thymine. The bases
used in DNA are adenine, cytosine, guanine, and thymine. In RNA they are adenine,
cytosine, guanine and uracil.
3.
There are a couple of important differences between prokaryotic and eukaryotic
genes. Firstly, prokaryotic genes are commonly arranged as operons or groups of genes
arranged by function whereas Eukaryotic genes that are functionally related are often
several thousands of bases apart. While both classes of genes have a promoter region,
where the machninery for transcription will bind, in prokaryotes the characteristics of the
region are the -35 and -10 region whereas in eukaryotes there are the TATA, CAT and GC
boxes. Eukaryotic genes also vary in that they have intron sequences that break up the
coding genetic material. These introns will be spliced out from a mature mRNA.
5.
The human protein MAGGTWYQLFPRKMWNDSTLHPFILPMNVAG would
correspond to a DNA coding sequence of:
ATG-GCC-GGC-GGC-ACC-TGG-TAC-CAG-CTG-TTC-CCC-AGG-AAG-ATG-TGG-AAC-GAC-AGCACC-CTG-CAC-CCC-TTC-ATT-CTG-CCC-ATG-AAC-GTC-GCC-GGC.
*I used the table on page 31 that gave the frequency of use for each codon and selected the
three digit code that had the highest frequency for each amino acid.
12.
In eukaryotic cells secretory proteins are processed in many complex ways before
they are released. The signal sequence of the protein is bound by a signal recognition
particle that directs the protein to a receptor on the surface of the membrane of the
endoplasmic reticulum. The secretory protein is passed through the translocon and the
signal sequence is removed by a signal peptidase. The protein is released into the ER
where it can be folded, glycosylated, and otherwise modified. Eventually the protein leaves
the ER in a vesicle via a budding event. The protein is transported to the cis side of the
golgi apparatus where additional glycosylation and other modifications occur. The protein
emerges from the trans face of the golgi in a vesicle destined for the plasma membrane. In
eukaryotes some proteins are constituitively released from the cell while others are
packaged and stored near the plasma membrane and are only released in response to
external stimuli.