Lecture 7 - Viruses, viroids and prions0

Lecture 7 - Viruses, viroids and prions0 - a. Single versus...

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Lecture Outline 7 – Viruses, Viroids and prions I. What is a Virus? A. Non-cellular; simply genes in a protein coat; lack metabolic machinery B. Need host to replicate; lack replication machinery C. Major cause of disease across all domains II. Discovery of Viruses A. Tobacco Mosaic Virus (TMV) – first virus isolated 1. Scientists deduced via experimentation that: a. TMV was a biological agent, smaller than bacteria, and needed host to replicate 2. Discovery of TMV highlights the logical deductive reasoning of science. III. Viral Structure A. Components 1. Capsid – outer shell of virus 2. Capsomer – functional unit of capsid 3. Membrane – host derived cell-membrane 4. Surface proteins B. Types 1. Helical 2. Icosohedral 3. Enveloped 4. Complex IV. Viral Classification (depends on genetic material and presence of an envelope) A. DNA (e.g. Herpes, pox, HPV) a. Single versus double stranded b. Enveloped versus non-enveloped c. Linear versus circular DNA B. RNA (e.g. SARS, hepatitis, rabies, measles, HIV)
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Unformatted text preview: a. Single versus double RNA b. enveloped versus non-enveloped V. Virus Life cycles A. General all viruses need host to replicate 1. virus enters cell 2. host cell replicates viral genome 3. viral genes transcribed 4. viral proteins / genes self-assemble 5. Completed virus departs cell B. Enveloped 1. Completed virus takes host membrane upon departure C. Retrovirus 1. transcriptase enzyme that reverse transcribes viral RNA to DNA 2. integrase enzyme that randomly inserts new DNA into cell genome Lecture Outline 7 Viruses, Viroids and prions D. Bacteriophage 1. Lytic (virulent; cell death via lysis eminent) 2. Lysogenic (temperate; cell death via lysis eventual) VI. Viroids A. No Protein coat; small circular genome; make no proteins B. Can be parasites of other viruses VIII. Prions A. Misfolded proteins B. Replicate by touching other normal proteins...
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Lecture 7 - Viruses, viroids and prions0 - a. Single versus...

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