Viruses121_OLS

Viruses121_OLS - Viruses 101 Viruses are obligatory...

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Viruses 101 Viruses are obligatory intracellular parasites: They absolutely require a host’s cellular machinery to replicate (multiply) 1890s: Dmitri Iwanowski and Martinus Beijerinck characterized the cause of tobacco mosaic disease as a “filterable virus” or “contagious living fluid” because the cause of the disease passed through filters that trapped bacteria 1930s: Wendell Stanley made crystals of this “filterable virus” suggesting that the cause of tobacco mosaic disease was not a living microbe but a chemical molecule 1930s: Scientists found that viruses could be “grown” in fertilized eggs and cells from living tissues 1940s: Tobacco Mosaic Virus finally visualized by electron microscopy Viral Structure 1. Genetic material (present in all viruses) A. May be either DNA (like bacteria and eukaryotes) or RNA, be linear or circular, occur in one segment or many 2. Capsid (present in all viruses) A. Protects the genetic material B. Provides attachment sites for host cells for naked (non-enveloped) viruses 3. Envelope (present in some viruses) A. Membrane surrounding the capsid
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This note was uploaded on 02/13/2012 for the course MBI 121 taught by Professor Balish during the Fall '08 term at Miami University.

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Viruses121_OLS - Viruses 101 Viruses are obligatory...

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