Study Guide for Exam 3 addendum

Viruses

1. What does it mean to be an obligate intracellular parasite? How could you grow a virus in the lab? How could you NOT grow a virus in the lab? How big is a virus? What shapes do they come in?

2. What are the essential parts that a virus is made of?  What are additional parts that certain viruses are made of? What is a viral envelope made of? Where does it come from?

3. If you have a cold virus and sneeze on your dog, why would you NOT expect your dog to come down with hepatitis? Give two reasons.

4. We have seen that the taxonomy of bacteria, Protists, and fungi is difficult. The classification of viruses is even worse. Why? What is the Baltimore scheme for trying to classify viruses?

5. Be able to describe the life cycle of a virus. How do you count how many viruses are in a sample? Some viruses grow in eggs. What is a practical consequence of developing vaccines by growing viruses in eggs?

6. What is the difference between a lytic cycle and a lysogenic cycle? What is a prophage? How does a virus benefit from becoming a prophage?

7. What is cell culture? How is growing a virus in cell culture often more useful than growing it in a whole organism?