Chapter 19 Notes

Chapter 19 Notes - Chapter 19 Notes: Viruses 19.1 A virus...

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Chapter 19 Notes: Viruses 19.1 A virus consists of a nucleic acid surrounded by a protein coat 1. The Discovery of Viruses a. Adolf Mayer, a German scientist, discovered that he could transmit a disease from plant to plant by rubbing sap extracted from diseased leaves onto healthy plants. He suggested that the disease was caused by an unusually small bacteria that were invisible under a microscope. b. Dimitri Ivanowsky, a Russian biologist, clung to the hypothesis that bacteria cuased tobacco moasic disease. c. Martinus Beijerinck carried out a classic series of experiments that showed that the infectious agent in the filtered sap could reproduce. He also saw the mysterious agent of mosaic disease could not be cultivated or nutrient media in test tubes or petri dishes. d. Wendell Stanley crystallized the infectious particle, now known as tobacco mosaic virus (TMV). 2. Structure of Viruses a. Viruses are infectious particles consisting of nucleic acid enclosed in a protein coat and, in some cases, a membranous envelope. b. They contain double-stranded DNA, single-stranded DNA, double-stranded RNA, or single-stranded RNA. c. The protein shell enclosing the viral genome is called a capsid. Depending on the type of virus, the capsid may be rod-shaped, polyhedral, or more complex in shape. d. Capsids are built from a large number of protein subunits called capsomeres , but the number of different kinds of proteins in a capsid is usually small. e.
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This note was uploaded on 02/07/2012 for the course BIO 1711 taught by Professor Burleson during the Spring '11 term at North Texas.

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Chapter 19 Notes - Chapter 19 Notes: Viruses 19.1 A virus...

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