1. Viruses
“They Are Not Alive!”

2. Viruses

3. Non-Living? Metabolize on their own Reproduce Move Take in food Grow
Viruses DO NOT:
Metabolize on their own
Reproduce
Move
Take in food
Grow
Consist of cells

4. What they can do is take a host cell “Hostage”

5. Bacteriophage Consist of a protein coat called a Capsid
Contain Viral DNA
Special Ligands allow the virus to attach to the cell receptors of a host cell.

6. Viral Infection
A virus can reproduce in two ways:
1.The Lytic Cycle: infects and affects the host cell very quickly. Flu, Ebola, Cold
2. The Lysogenic Cycle: infects but does not affect immediately HIV, Herpes

7. The Lytic Cycle

8. The Lysogenic Cycle INCUBATION PERIOD Explain Lyogenic Cycle
Click and compare to lytic cycle.

9. Lytic Cycle Animation Lytic Cycle #2 Virus Attack H1N1
Lytic Infection PH

10. Viral Infections Small Pox Chicken Pox Herpes Hanta Mumps Measles
Polio
Hepatitis
West Nile
Corona
Encephalitis
Influenza
Meningitis
Ebola
HIV
Lassa Fever
Mononucleosis
Rabies
Dengue Fever
Yellow Fever
H1N1 (Swine Flu)

11. Vaccines Vaccines are used to establish immunity.
They can be made of weakened viruses or “dead” viruses.
The body recognizes and destroys the viruses. It will “remember” them so that the next time they are in the body, they will be destroyed.
Ex. The H1N1 Shot

12. More Human Viral Diseases
Chicken Pox
Mumps
Herpes
Hepatitis
Warts
How big are Viruses?

13. Viroids and Prions Viroids
Infections agents composed of a single, circular strand of RNA. They are not protected with a protein coat.
Viroid RNA does not code for any known protein.
Mostly affect plants but recently have been found to affect humans.

14. Viroids and Prions Prions An infectious particle made of protein
Affect the brain or neural tissue.
All are untreatable and fatal
Ex. Mad Cow Disease