1. Why are viruses dangerous?

2. Viruses Host Parasitic Relationships Shapes of Viruses Lytic Cycle Lysogenic Cycle

3. Viruses Not cells b/c no cytoplasm or organelles. Basic structure is some form of genetic material in a protein coat. Invades a cell and destroys it

4. Viruses Cont. Found everywhere Ex. 5 billion in 1 drop of blood. Ever changing Ex. Colds, flu, and AIDS

5. What do viruses look like?

6. Virus Shapes Crystals Ex. Polio virus Spheres Ex. Influenza and HIV virus

7. Virus Shapes Cont. Cylinders Tobacco Mosaic virus Spacecraft Attacks only bacteria.

8. How do viruses survive in the environment?

9. Host Viruses don’t eat, grow, breathe, or perform biological functions. Viruses reproduce inside a host cell. Viruses have parasitic relationships. They reprogram the cell.

10. So, how does the virus get inside the host? And, what does it do there? Reproduce!

11. The Lytic Cycle 1.The virus finds a host. 2.Enters the cell or genes are injected. 3.Genes reprogram the host cell into a virus “factory”. 4.New viruses break out to find a new host cell.

13. Lysogenic Cycle Inactive virus genes that wait inside the cell until after the host cell divides. Changes in environment and stress can cause the virus to become active.

14. How do we treat virus?

15. Immune System White blood cells attack and engulf anything that is not suppose to be in the body. A “plan of attack” is kept in the body in case you get the same virus again. Ex. Killer T Cells and Helper B Cells

16. Vaccines Edward Jenner developed the first vaccine in the late 1700’s. It was for small pox. A vaccine is a weakened or inactive virus used to develop immunity against viruses.

17. Explain why virus are so dangerous. Use terms and concepts we discussed in class today.