Monday, November 4, 2013

November 4, 2013:
Lecture Topic(s):
Chapter 44: Viral Classification, Structure and Replication,


Reading Assignments from:

Medical Microbiology, 7th edition
Patrick R. Murray, Ken S. Rosenthal, Michael A. Pfaller
Elsevier Saunders, Philadelphia, PA


Homework Assignment: (based upon the reading assignment)
To assist your understanding of the assigned readings, please answer the following questions in the space below:

1. How do viruses reproduce? Describe the basic components of a virion (see Figures 44-1 and 44-2 on p.394). Describe how viruses are classified and named (see Box 44-3, p. 394).

2. What is the difference between capsid viruses (Box 44-4, p. 396) and enveloped ones (Box 44-5, p.396)?

3. What common sports ball represents the icosadeltahedron shape?

4. What are the major steps in viral replication (See Figure 44-9 and Box 44-6 on p.399)? What in particular happens in the early phase of infection? In the late phase? What is the burst size and why are defective particles sometimes formed?

5. Describe how viruses recognize and attach to target cells. What kind of molecules serve as virus receptors? What is meant by terms such as, “host range” and “tissue tropism”?

6. In terms of viral penetration, what is the difference between endocytosis and viropexis?

7. How can the pH of the cell affect the uncoating of virus from its capsid or envelope?

8. Describe the steps in viral macromolecular synthesis (See Figure 44-11, p. 401).

9. List several properties of DNA viruses (See Box 44-7 on p.403).

10. What kind of virus is herpes simplex virus? Describe the replication of this virus (see Figure 44-12, p. 402).

10. List several properties of RNA viruses (See Box 44-8 on p.404).

11. What kind of virus are picornaviruses? Describe the replication of this virus (see Figure 44-13, p. 404). What kind of virus are rhabdoviruses? Describe the replication of this virus (See Figure 44-14, p.405).

12. Describe several ways by which genetic exchange between viral particles can give rise to new viral types (See Figure 44-15, p. 407).