Unit 4 (25 points)

Read each question carefully and answer them. you are expected to do your own work and for the short answer questions write the answers using your own words (points will be deducted for answers quoted or copied from the modules, textbook, or other sources).

You must provide complete citations in APA format (you don’t need to double space) for the sources of information you used to support your answers for the questions in Part B. If you include them at the end, then include in-text citations.  The topic title should be included in citations from the course modules and other multi-topic sources. No credit for questions without citations. Some unacceptable sources: Wikipedia, Yahoo Answers and similar type websites

Part A. Multiple Choice and Fill in the Blank (1 point each)

  1. What can you conclude about a virus that can still cause disease after it has been exposed to DNase (an enzyme that destroys DNA)?
  2. The virus has a DNA genome
  3. The virus has an RNA genome
  4. The virus has a double stranded RNA genome
  5. The virus has both a DNA and an RNA genome


  1. Which of the following structures is responsible for the changes in influenza viruses that requires the development of a new vaccine each season?


  1. changes in the envelope phospholipids
  2. changes in the surface spike proteins
  3. changes in the internal capsid proteins
  4. all of the above


  1. Retroviruses are named because their reverse transcriptase
  2. reverses the action of drugs on viruses.
  3. reverses the ability of viruses to associate with cells.
  4. reverses the response to antibiotics.
  5. reverses the flow of genetic information from RNA to DNA.
  6. all of the above.
  7. A virus obtains its envelope during which of the following phases?


  1. Attachment
  2. Uncoating
  3. Penetration
  4. Release
  5. Assembly
  6. How can an individual end up with spongiform disease?
  7. Eating meat with PrPSc (infectious PrP-res)
  8. Inherited a mutation in the gene coding for PrPc (PrP-sen)
  9. A spontaneous mutation that changes the PrPc form to the PrPSc form
  10. All of the above
  11. Which of the following components is brought into a cell by HIV?
  12. a DNA-dependent DNA polymerase
  1. RNA polymerase
  2. ribosome
  3. reverse transcriptase
  1. Which of the following leads to emergence of a new infectious disease in humans?
  1. a mutation that allows it to infect humans
  2. a period of decline in vaccination rates
  3. a change in disease reporting procedures
  4. better education on the signs and symptoms of the disease

Part B. Short Answers

Answer the questions below as completely and as thoroughly as possible and where appropriate include a specific example to illustrate. Answer the questions in essay form (not as an outline or bullets) using complete sentences. You may use a diagram or table to supplement your answers, but a diagram or table alone without appropriate discussion will not be adequate for full credit.

Reminder: All answers must be written in your own words and include complete and accurate citations for the sources you used or that support your answer. No points will be earned for answers without citations or with incorrect citations. Citations for the course modules must include the section topic.

  1. (4 points) What are the mechanisms by which mature enveloped and non-enveloped viruses enter and leave a host cell? Briefly describe the processes and name an animal virus for each.


  1. (4 points) Describe the steps from viral attachment to the host cells and translation of the HIV genome in the host cell and the role of the viral enzyme reverse transcriptase in the process. Include the names of the stages of the life (replication) cycle.


  1. (3 points) How do viruses cause disease (the effect(s) on host cells or tissues that cause disease)? Name a specific virus and the disease it causes and how it causes the disease. This is not about the stages of the virus life cycle.


  1. (4 points) Name the structural components common to viruses and describe the function of each. Describe at least three structural characteristics that contribute to the high diversity in types of animal viruses and give examples to illustrate the differences.


  1. (3 points) State the normal function of proto-oncogenes and describe how some viruses may contribute to the development of tumors by altering proto-oncogenes. Name two oncogenic viruses and the type of cancer they cause.