Liberty
University BIOL 101 Individual Assignment 3 solutions answers
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The global community is plagued by
increasing incidence of lung cancer, colorectal cancer, breast cancer, pancreatic
cancer, prostate cancer, leukemia, non-Hodgkin lymphoma, liver cancer, ovarian
cancer, and esophageal cancer. Other types of cancer exist but are less
frequent. What is the scientific community doing to attempt to eliminate the
most common forms of cancer that are ravaging society?
1. Be certain that you have read your
textbook’s chapter on cell division, specifically the last section on how cells
become cancerous. This is context for completing this assignment.
2.
Watch
the presentation (found in the Reading & Study folder of Module/Week 4)
entitled “Ways to Fight Cancer.” Notice that the presentation outlines
essentially 3 approaches to fighting cancer: a) reduction of cancer risks, b) correction
of cancer genes, and c) destruction of cancerous tissue.
3.
In
the “Individual Assignment 3: 10 Discoveries in the War on Cancer” document is
a set of 10 scientists’ discoveries. Scan the discoveries briefly. Then open
the assignment submission link in Module/Week 4. In the text box, number from 1
to 10 for the 10 discoveries listed in the document.
4.
Reflect
carefully on the first discovery (#1). Would this discovery be more useful for
(a) reducing cancer risks, (b) correcting/restoring cancer cells to normal, or
(c) destroying cancerous tissue? After #1 in your list, place in parentheses
the letter representing the approach to fighting cancer that will best be served by this new discovery. (More
than one approach may be served, but which is most likely to be helped most
significantly?)
5.
Repeat
this analysis for each of the remaining 9 discoveries. Return to the “Ways to
Fight Cancer” presentation as needed for additional perspective. When finished,
your entire text box must be simple: a numbered (1–10) list of letters a, b, or
c.
6.
Seven
points are granted for each correct association, up to 8 correct. If you get
any 9 correct out of 10, you get a perfect score (60 points) on the assignment.
Individual Assignment 3: 10 Discoveries in the War on Cancer
1. Malignant
brain tumors in adults are fast-growing cancers with median survival rates of 15 months, even with aggressive
treatment. Researchers have been searching for genetic “signatures”
(characteristic groups of cancer-causing genes) that could help in defining the
kind of brain tumor the patient has. They hope to be better able to predict
the course of the disease and the
patient’s response to treatment.
2.
Tobacco
smoking is the leading cause of preventable deaths worldwide. It is a risk
factor for lung cancer and several other types of cancer. Results of analysis
of the entire human gene collection (the “genome”) support some previous
findings that a region of human chromosome number 15 contains one or more genes that are associated with smoking intensity (the
number of cigarettes smoked per day) and the closely related trait of nicotine dependency.
3.
Immunologists are
investigating ways to destroy lymphocytes (white blood cells of the immune
system) that have become cancerous (lymphomas). A current drug, Rituxamab,
contains antibodies that bind to the surfaces of these lymphocytes, setting
them up for destruction by the cancer patient’s own immune system. They are
currently seeking ways to modify the antibody’s structure so that it will
attract the cancer patient’s “natural killer” (NK) cells to the lymphocytes.
Success of this project will bring a multifaceted immune response against
lymphomas and hasten their destruction.
4.
Virologists are modifying lentiviruses
as vectors for carrying proto-oncogenes into cancer-transformed cells in
culture. They are developing this virus for inserting the ras proto-oncogene directly into its correct location in the
genome. The correct ras gene will
already be linked to human DNA to either side of it and complexed with a
recombination enzyme that will insert it into its correct location within the
human genome. At the same time, the recombination enzyme will excise the
defective oncogenic form of ras. The
cells in culture should again come under normal hormonal control and require
extra-cellular signals in order to continue dividing.
5.
Immunologists are working with a
mutation (HER2) that is expressed on the surface of many breast, bladder, pancreatic,
and ovarian cancer cells. They have made antibodies against this mutant surface
protein. These antibodies have been covalently bonded to a “gene expression
vector” that makes cells light up when incubated with luciferin from fireflies.
The vector takes the gene for luciferin into the cancer cells. The researchers
have shown that their antibody can accurately find and light up cancer cells.
Their next step is to bond the antibody to an expression vector that carries
the normal HER2 gene into mutant cancer cells.
6.
Biochemists have discovered a protein
kinase enzyme named BRAF that is an important link in a molecular pathway that
causes a cell to divide. Normally BRAF responds to signals coming from outside
the cell—signals calling for the cell to divide normally under normal
conditions. But there is a mutation in BRAF enzymes that causes it to activate
the cell toward division continually. In this way it results in melanomas,
thyroid, and ovarian cancers. Biochemists have also found a drug, vemurafenib,
that binds selectively to mutant BRAF, totally inactivating it. Cells that have
inactivated BRAF undergo apoptosis, a process that leads to cell death.
7.
Organic chemists are exploring
structural variations of the organic compound avobenzone (1-(4-Methoxyphenyl)-3-(4-tert-butylphenyl)
propane-1,3-dione) for inclusion in sunblock products. Avobenzone is known for
its ability to absorb a broad spectrum of ultraviolet radiations, including UVB
light (known to enhance the frequency of basal cell and squamous cell
carcinomas [skin cancers]) and UVA rays (thought to increase the frequency of
melanoma cancers). New variations in the structure of avobenzone are hoped to
retain the ability to absorb harmful UV radiation while having an increased
stability in the presence of that radiation.
8. Molecular
biologists have taken nanoparticle-sized
spheres and used them to deliver a cell-killing toxin from bee venom to tumors in mice,
substantially reducing tumor growth without harming normal body tissues.
Nanoparticles are known to concentrate in solid tumors because blood vessels in
tumors show “enhanced permeability and retention effect,” or EPR. Hence,
substances such as nanoparticles escape more readily from the bloodstream into
tumors and the generally poor drainage of lymph from tumors further helps trap the
particles in tumor tissue.
9. Biochemists are analyzing the many,
many components of red meat (beef, pork) to determine which component, if any,
will cause increased colorectal cancer rates in mice when the component is
administered orally. Studies have shown that higher colorectal cancer rates in
humans are associated with higher consumption rates of red meat.
10. Molecular biologists have developed a new sequence of human genes called
an ankyrin
insulator sequence. You place a new, corrected, or therapeutic gene within this
sequence. Its role is to create an active area on a human chromosome where the
new gene can work efficiently no matter what chromosome it lands on.
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