BIOLOGY 2EE3 Lecture Notes - Lecture 5: Dmitri Ivanovsky, Tobacco Mosaic Virus, Aids
4 Feb 2018
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Document Summary
In the late 1800s, infectious disease tobacco mosaic virus (tmv) was isolated in a filter by dmitri ivanovsky, then beijerinck: he was co-discoverer of bacteriophages (viruses that infect bacteria) 1901: walter reed showed that yellow fever is caused by a filterable virus. Felix d(cid:495)(erelle (cid:523)april (cid:884)5, (cid:883)(cid:890)(cid:889)(cid:885)(cid:524) was a french-canadian microbiologist. Obligate intracellular parasites: (cid:498)take-over(cid:499) transcription, translation of machinery host, diameter between 10 and 100 nm (1nm = 10^-9 meter, polio virus 30 nm; pox virus 200 nm long, genomes between ~5000-200,000 nt in length. Enveloped viruses: have a lipid bilayer around the capsid. Genome single or double-stranded dna or rna. Most linear, or circular and a few where the genome is segmented. Nucleic acid and capsid are called nucleocapsids. Nucleocapsids can be icosahedral or helical in shape. Bacteriophages often have an icosahedral head and helical tail: e. g. , influenza a eight segments of ss rna 11 proteins. Dna and rna are enclosed in a protective shell the capsid.
