1. The Nature of Viruses
Chapter 27

2. Structure of Viruses

3. Types of Viruses
DNA
RNA
Retroviruses

4. Main Shapes
Helical
Icosahedral

5. Sizes of Viruses

6. How Viruses Replicate 1. Attach to and Enter Host Cell
2. Take over Protein synthesis machinery inside of cell- Lysogenic Cycle
3. Lytic Cycle- Lyse out of cell to go make more Virus Babies

7. Retroviruses
Use Reverse Transcriptase to make Viral RNA into DNA – HIV is a Retrovirus

9. Who can get a virus? Just about every kind of organism
Obligate intracellular parasites
Host Range and Tissue Tropism
Hep- liver
Rabies-neurons
Chickenpox…..can you ever really get rid of it?

10. HIV AIDS first reported in the US in 1981
Originated in Africa in the 1950’s based on the rate of mutation
Closely related to a chimpanzee virus

11. Some people are resistant to HIV How?
Recent research suggests that people who were immuned to smallpox may also be immuned to AIDS
Due to a mutation in CCR5 receptor
Makes virus unable to bind to cells and enter.

12. How the HIV Infection Works

13. Treatments Combination Drug Therapy Vaccine Therapy Chemokines and CAF
AZT and Protease inhibitors
Vaccine Therapy
Chemokines and CAF
Blocking CCR5

14. Other Viruses Flu Emerging viruses Viruses can cause cancer
Recombination vs mutation
Emerging viruses
Ebola
Sars
Hantavirus
Viruses can cause cancer

15. Prions and Viroids Prions- misfolded protein
TSE’s are caused by prions
Why is this controvericial?
Viroids- infections RNA with no protein coat.