BIOL240 Lecture Notes - Lecture 5: Lysogen, Plaque-Forming Unit, Prophage
4 Nov 2017
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Document Summary
Viral diseases have plagued humans since before we even knew what they were (e. g. , smallpox in egypt) Infectious tobacco mosaic virus isolated in ltered, bacteria-free uid. Felix d"heurelle discovered bacteriophages (coined term plaque) Walter reed and colleagues showed that yellow fever was a virus transmitted by mosquitoes, in 1901. Typically between 10 and 100nm, contains -> dna, protein, membrane. Genome typically a few thousand to 200,000 nucleotides long. There are exceptions to the small size of viruses. Megavirus chilensis (dsdna virus of amoebas) has a genome >1. 2 megabase pairs, encodes 1,200 proteins. Mimivirus (dsdna virus of amoebas) can be 400nm in diameter, with a 1. 2 mega base pair genome coding for 979 proteins (mimics bacteria, looks gram-positive) Pandoravirus (2013; dsdna virus of amoebas) with approx. 2. 5 megabase genome, 1 micron in diameter (size of many bacterial cells) Single or double-stranded dna or rna (linear or circular)
