1. D7 - Antivirals Differences between bacteria and viruses How does antiviral drugs work? The AIDS problem

2. D.7.1 How do viruses differ from bacteria?

3. List the differences you know of between bacteria and viruses. BacteriaViruses

4. List the differences you know of between bacteria and viruses. Bacteria Microscopic Has single, circular strand of DNA—is able to manufacture RNA from the DNA. Cell wall Can reproduce on its own. Viruses Submicroscopic Has either a section of DNA or RNA surrounded by a coat of packed protein units called capsomeres. No cell wall Can’t reproduce without a living host. Takes over cell’s machinery to produce more viruses.

5. D.7.2 Describe the different ways in which antiviral drugs work

6. Describe the different ways in which antiviral drugs work. Well known viral infections Common cold Influenza (Including H1N1) HIV/AIDS Chicken Pox Herpes/warts What is the body’s natural defense to viral infections?

7. The body’s natural defense to viral infections Fever Coughing Sneezing Runny nose Diarrhea Vomiting

8. Different ways in which antiviral drugs work Viruses multiply very quickly, so antiviral drugs will often have little effect by the time symptoms appear. Goal of antiviral drugs is to stop virus replication DNA/RNA modification Stop viruses to leave infected cells

9. Acyclovir and ganciclovir Acyclovir is used as a cream or orally to fight herpes viruses. Gancyclovir is used for genital herpes or when viruses has become resistant to acyclovir Shortens the time of the outbreak, but does not prevent recurrences It stops replication of viral DNA, and prevents virus from multiplying Acyclovir Gancyclovir

10. Amantadine and rimantidine Prevent new viruses from leaving the cell Used to treat influenza. It inhibits the active site of neuraminidase, an enzyme which helps the virus to stick to the cell wall Amantadine Rimantidine

11. D.7.3 Discuss the difficulties associated with solving the AIDS problem

12. HIV (Human Immunodeficiency Virus) A retrovirus (contains RNA) Is acquired by sharing bodily fluids with someone whos is infected with HIV Can lead to AIDS (Acquired Immune Deficiency Syndrome). Attacks white blood cells called T helper cells (T4-cells) T helper cells activate the immune system- the body is rendered unable to fight infections When invading a cell it starts making DNA from it’s RNA with an enzyme called reverse transcriptase HIV

13. HIV, cont. One of the problems with antiviral drugs for HIV is the virus is constantly mutating A drug called AZT (zidovudine) has been used to inhibit the reverse transcriptase, and this does not affect normal cells AZT has been effective in prolonging the period until AIDS develops AIDS medicins consist of a coctail of antivirals

14. Structurally similar? AZT (zidovudine)Acyclovir

15. Solving the AIDS problem… What can we do today?

16. Solving the AIDS problem… Develop new antivirals Develop vaccins Prevent people from getting HIV, e.g. by using condoms