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D7 - Antivirals. Differences between bacteria and viruses How does antiviral drugs work ? The AIDS problem. D.7.1. How do viruses differ from bacteria?. List the differences you know of between bacteria and viruses. Viruses. Bacteria.
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D7 - Antivirals • Differencesbetweenbacteria and viruses • Howdoes antiviral drugswork? • The AIDS problem
D.7.1 • How do viruses differ from bacteria?
List the differences you know of between bacteria and viruses. Viruses Bacteria
List the differences you know of between bacteria and viruses. 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. Bacteria • Microscopic • Has single, circular strand of DNA—is able to manufacture RNA from the DNA. • Cell wall • Can reproduce on its own.
D.7.2 • Describe the different ways in which antiviral drugs work
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?
The body’s natural defense to viral infections • Fever • Coughing • Sneezing • Runnynose • Diarrhea • Vomiting
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
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 Gancyclovir Acyclovir
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 Rimantidine Amantadine
D.7.3 • Discuss the difficulties associated with solving the AIDS problem
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
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
Structurallysimilar? AZT (zidovudine) Acyclovir
Solving the AIDS problem… • Whatcanwe do today?
Solving the AIDS problem… • Develop new antivirals • Develop vaccins • Preventpeople from getting HIV, e.g. by usingcondoms