Medicines and Drugs Anti-virals Julia Barnes Anna Cruickshank

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.

Virus vs. Bacteria 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 Structure

Click on Picture

Antiviral Drugs 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

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! phics/ribbons/help/dna_rgb.gif ety_mode=true&persist_safety_mode=1

AIDS Acquired Immune Deficiency Syndrome 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

HIV Invasion Process Click on Picture

Possible AIDS Drugs 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

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

For 5 Points… What is one difference between bacteria and a virus? 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 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

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

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

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

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