Fall 1998 Biology 111 Exam #4 - Cancer, HIV and Transgenics

There is no time limit on this test, though I have tried to design one that you should be able to complete within 2.5 hours, except for typing. You are not allowed to use your notes, old tests, any electronic sources, any books, nor are you allowed to discuss the test with anyone until all exams are turned in by noon on Friday December 18. EXAMS ARE DUE BY NOON ON FRIDAY DECEMBER 18. Remember that I will be out of town Dec. 12-17 but will be in my office all day Dec. 18th. You may use a calculator and/or ruler. The answers to the questions must be typed on a separate sheet of paper unless the question specifically says to write the answer in the space provided. If you do not write your answers on the appropriate pages, I may not find them unless you have indicated where the answers are. There are 4 pages to this exam, including this cover sheet.

If you want to turn in your final December 12 - 17, give your test to the Biology secretary in Watson. I will be back Dec. 18th to start grading the exams at 12:01 pm Dec. 18th.

- 3 pts if you do not follow this direction.

Please do not write or type your name on any page other than this cover page. Staple all your pages (INCLUDING THE TEST PAGES) together when finished with the exam.

Name (please print):


Write out the full pledge and sign:

Here is the honor code

"On my honor I have neither given nor received unauthorized information regarding this work, I have followed and will continue to observe all regulations regarding it, and I am unaware of any violation of the Honor Code by others."


How long did this exam take you to complete (excluding typing)?


Lab Questions:

6 pts.
1 a. Using the graph paper provided below, calculate the molecular weight of the band below the question mark. You must draw a graph here to get credit for your answer. The black arrows on the side of the gel point to the bottoms of the wells. The molecular weights (in kilobase pairs) of bands in the marker lane are indicated next to the appropriate bands.
b. This band of DNA represents a locus that contains a VNTR. If there were zero repeat units (each repeat unit is 32 base pairs long) in this target sequence, it would have been 111 base pairs long. How many repeat units are present in this VNTR alllele? Show your work.

The DNA band is _______ base pairs long.

This band has _________ repeat units in it.


4 pts.
2) DNA fingerprints are very helpful in legal cases. Tell me why it is used more successfully to find a person innocent rather than guilty.

Lecture Questions:

7 pts.3) a) Describe the structure of MPF.
b) Describe the mechanism that permits MPF activity to rise and fall through the cell cycle.
c) Which phase of the cell cycle has the highest MPF activity?

6 pts.
4) How do carcinogenic mutations differ from other mutations? Give a specific example of a cancer-causing mutation as a part of your answer.

6 pts.
5) What are tumor suppressors and what genetic changes must be present in them in order for a person to develop cancer?

4 pts.
6) Describe the intracellular antibody binding studies that linked c-ras to the response of a cell to growth factors.

8 pts.
7) a) By what mechanism does HIV become latent?
b) Name one drug used to block this phase of infection and describe how the drug works.

9 pts.
8) a) Describe the genome of HIV.
b) List 4 different proteins your cells supply for HIV.
c) List 3 proteins HIV supplies.

6 pts.
9) Describe the relationship between gp160 and CD4.

4 pts.
10) Why do strategies for producing anti-viral agents differ dramatically from those used against bacteria?

8 pts.
11) a) Draw a pedigree for a family that has two parents, and four children (two girls and two boys). In this family, indicate that the mother and any two of the children have developed cancer.
b) Would a family that has inherited an oncogene or a family that has inherited lack of tumor suppressors be more likely to develop cancer? Explain your answer.

6 pts.
12) When a person is determined to be HIV+, what does that mean and how is that determined?

4 pts.
13) Describe how gene therapy might be used to generate a T-cell mediated vaccine for HIV.

6 pts.
14) Briefly describe how Dolly the sheep was cloned.

8 pts.
15) Explain the significance in signal transduction why it is important to turn off the signal. Use a specific example in your answer that ties in with cancer.

8 pts.
16) a) What is produced in the light reaction that is consumed in the dark reaction?
b) What is produced in the light reaction that is NOT consumed in the dark reaction?
c) What would the problem be if humans could NOT perform glycolysis or the citric acid cycle, but we could perform the light reactions?

+2 pts.
For extra credit
p53 is a very well known tumor suppressor that is involved in surveying DNA to make sure there are no mutations that need repair. Explain why it is advantageous to have p53 block exit from G1 rather than exit from any other step in the cell cycle.

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© Copyright 2001 Department of Biology, Davidson College, Davidson, NC 28036
Send comments, questions, and suggestions to: macampbell@davidson.edu