Medicines and Drugs

1. Medicines and Drugs Anti-virals Julia Barnes Anna Cruickshank

2. Objectives • D.7.1 State how viruses differ from bacteria. • D.7.2 Describe the different ways in which antiviral drugs work. • D.7.3 Discuss the difficulties associated with solving the AIDS problem.

3. Acellular Not living Don’t metabolize energy or produce ATP Cannot reproduce independently Usually surrounded by a protein capsid as well as a cell membrane No nucleus or cytoplasm Have DNA or RNA 100 nm (nanometers) Cellular Living Do metabolize energy and produce ATP Do reproduce independently Maintain a cell membrane but not a protein capsid Nucleus and cytoplasm Have DNA or RNA 1000 nm Virus vs. Bacteria

4. Virus vs. BacteriaStructure

5. Click on Picture

6. How the virus works Invades host cell Using enzymatic processes the virus stimulates the host cell to produce viral nucleic acid Viral nucleic acid is coated with protein and released from host cell How antivirals work Chemically block enzyme activity in host cell This stops the virus from replicating Altering the host cell’s ribosomes, making them useless to the virus Antiviral Drugs

7. More Specifically… Possiblities for Intervention • Alteration of host binding site • Alteration of cell wall • Prevention of virus losing its protein coat • Blocking reverse transcriptase • HIV and AZT • Altering genetics of virus • Prevention of virus exit from cell • Influenza and amantadine YA! MOVIE! http://www.csb.yale.edu/userguides/graphics/ribbons/help/dna_rgb.gif http://www.youtube.com/watch?v=RO8MP3wMvqg&feature=related&safety_mode=true&persist_safety_mode=1

8. HIV Retrovirus (RNA instead of DNA) Attacks white blood cells – disables immune system Uses reverse transcriptase to make DNA copies off of the virus’ RNA AIDSAcquired Immune Deficiency Syndrome

9. HIV Invasion Process Click on Picture

10. Chemical group - nucleoside analog reverse transcriptase inhibitors AZT (3'-azido-3'-deoxythymidine) sold under Retrovir or Retrovis Inhibits reverse transcriptase enzyme Does not inhibit normal cell activity Possible AIDS Drugs

11. Difficulties With Treatment Generally • Speedy reproduction • Fast evolution and mutation • Thousands of reproduced viruses by the appearance of symptoms • Difficult to entirely eliminate viruses • Oral herpes treated with acyclovir

12. For 5 Points… • What is one difference between bacteria and a virus? • Cellular • Living • Do metabolize energy and produce ATP • Do reproduce independently • Maintain a cell membrane but not a protein capsid • Nucleus and cytoplasm • Have DNA or RNA • larger • Acellular • Not living • Don’t metabolize energy or produce ATP • Cannot reproduce independently • Usually surrounded by a protein capsid as well as a cell membrane • No nucleus or cytoplasm • Have DNA or RNA • smaller

13. For 10 Points… • What must a virus have before it can replicate or reproduce? A host cell

14. For 15 Points… • What are TWO ways antivirals alter the host cell? Blocking enzyme activity or altering the ribosomes

15. For 20 Points… • What is the name of the capsule containing the viral RNA? The Capsid

16. For 25 Points… • Name a possible AIDS medicine and what it does in the cell. AZT blocks reverse transcriptase enzyme