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Viruses1 - We have Single stranded DNA type Strand can be...

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Viruses: I. Taxonomy--We use the same scheme eg. Class, Order, Family, Genus, Species. We don't need to go higher than Family for all common viruses. A. Examples of families: Picornaviridae, Poxviridae, Retroviridae. B. Genera have the suffix "virus" after them. For Picornaviridae Enterovirus (alimentary tract) species e.g. poliovirus 1, 2, 3 cardiovirus (neurotropic) species e.g. mengovirus ;rhinovirus (nasopharyngeal region) species e.g. Rhinovirus 1a apthovirus (cloven footed animals ) species e.g. FMDV-C hepatovirus (liver) species e.g. Hepatitits A virus C. Species is most difficult to assign. For example if we look at the immunodeficiency viruses we have: Retroviridae, lentiviruses, then HIV 1 HIV 2, SIV, BIV, Visna virus, FIV and so on. But there are many transitional genotypes in between, for example HIV 1 and HIV 2. Where do we put them. Strains? II. Virus types based on nucleic acid type and covering. We have: Double stranded DNA type example is T bacteriophage.
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Unformatted text preview: We have Single stranded DNA type. Strand can be sense strand or a negative sense strand. We have RNA Viruses: 1. Positive sense strand RNA = mRNA 2. We have negative sense strand RNA, which must make a + strand, or do reverse transcription = Retroviridae = HIV and cancer causing viruses. 3. RNA viruses mutate like crazy. They don't have the repair enzymes available to them for replication. Also, virus is so small that RNA would have to be significantly larger to make an enzyme. One 100 amu amino acid needs 1000 triplet to code for it. What restriction does that place on the virus? This is why protein coat is usually made of 2 or 3 proteins that are made by the genome over and over and then assemble into simple geometric shapes like a 3-D Jigsaw puzzle. Virus can use the same gene over and over instead of having more nucleic acid, which could not pack into a multiprotein coat....
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Viruses1 - We have Single stranded DNA type Strand can be...

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