The purpose of this exam is to test your knowledge and understanding of key concepts. Answer the following questions in your own words. Type or write legibly. Answers with more than 20% of the sentences and phrasing copied directly from a book or handout or from another student do not demonstrate understanding and will receive zero credit. The exam is due back by 5:30 pm, Tuesday, April 13th.

1. Explain the principles of the polymerase chain reaction (PCR). Include the importance of primers, thermocycling, thermus aquaticus. Explain why the number of DNA molecules goes up so quickly as the number of cycles increases. Explain how PCR can be used in a criminal investigation.

2. Regarding molecular biology techniques:

Explain gel electrophoresis, autoradiography, avidin-biotin detection techniques and FISH. Explain the difference between Southern, Northern, and Western Blots and how the names were derived.

3. Explain the molecular biology and genetics of cystic fibrosis. On a molecular level, why is a defect in the cystic fibrosis gene harmful? Explain how genetic engineering can be used to treat the disease.

4. Regarding your immune system:

Explain briefly the function of T-cells versus B-cells. Details of the molecular biology of B-cells are not necessary in your explanation. Explain the function of killer T-cells versus helper T-cells. Explain the MHC and CD4 proteins and their role in the binding of T-cells to other cells.

5. Regarding viruses and plasmids:

Define what is a virus and define what is a plasmid. Explain how a virus can take over your cellular machinery. What are the possible different types of viral genome? Explain how plasmids could be used to help convert waste paper into alcohol as an energy source.