Unit #2 Review – Cells and Viruses

1. Retroviruses, although not considered to be alive, attack host cells and cause disease. The attack of a host cell is necessary for the virus to survive for what reasons?

2. List the characteristics of a virus and a bacteria?

3. Label the diagram

4. Draw the two cycles for viral reproduction

5. What is the difference between antibiotic and a vaccine? 6. Analyze the graph to the right.

7. List the viruses associated with this shape and what do the spikes on the outside do?

8. What is the type of non-living material that is enclosed in a protein coat and the coat has spike-like projections all over its surface?

9. What would be the MOST promising method of developing a new type of drug to attack invading viruses? 10. Cell theory states: all living things are composed of one or more cells; a cell is the smallest unit that still retains the properties of life; and new cells only come from cells that already exist. Based on cell theory, why is a virus considered non-living?

11. Smallpox is a virus with a fatality rate of about 30%, and those that survive, the disease causes terrible scarring and lingering problems. Edward Jenner is famous for a now notorious experiment, in which he developed the first vaccine for smallpox. In the experiment, Jenner first exposed a small boy to cowpox, which is relatively harmless. The boy got cowpox and then recovered. Jenner then exposed the boy to smallpox by walking him through a hospital ward. The boy lived. What would be a good conclusion for this experiment?

12. The virus that causes mumps in humans is composed of a protein outer shell containing a core of DNA. The virus that causes the flu in humans is composed of a protein outer shell containing a core of RNA. Vaccines that are effective against mumps work efficiently year after year. Vaccines that work against the flu must be revised and changed every year. What accounts for the difference in the effectiveness of these two vaccines?

13. How are the lytic viruses different from the lysogenic viruses?