Lecture 08 Outline Chapter 19

Lecture 08 Outline Chapter 19 - Crampton Bio II Lecture 8...

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Crampton Bio II - Lecture 8 VIRUSES Slide 1: What Are Viruses? Among simplest of biological systems Very small (20 – 300) nm (nm = 10 -9 m) Slide 2: What Are Viruses? Not placed in the three domain system. Why? 2. They have a genome, and replicate – but can only do so within the cell of a HOST Viruses subvert host’s replicating systems to copy themselves Viruses are obligate intracellular parasites Slide 3: Are viruses alive? Exhibit some properties of life: 1. They replicate and undergo Darwinian evolution i. Structure of protein coat ii. Modification of host phenotype Slide 4: Are viruses alive? Some properties of life absent: No metabolism When alone viruses are completely DORMANT: no biological activity ACTIVE viruses manipulate host metabolism Slide 5:
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First isolated from tobacco plant… the tobacco mosaic virus Initial identification proved difficult. Could not be seen by microscopes of the time. Slide 6: EXPERIMENT: Disease caused by biological agent. Infectious agent contained in the sap Slide 7: EXPERIMENT: Must be a “very small” bacteria Slide 8: EXPERIMENT: Tobacco disease definitely caused by a replicating agent: (not a toxin). After several rounds of dilution: still able to cause disease Slide 9: EXPERIMENT: Will not grow in culture TMV needs the host to replicate! Slide 10: Summary: Tobacco disease was caused by: Biological agent , Smaller than bacteria, Needed host to replicate Slide 11: Stanley crystallized TMV and imaged it with electron microscopy Slide 12: Cells don’t crystallize Nucleic acids do So do viral proteins/nucleic acids- unusual property of viruses is that they will crystallize
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This note was uploaded on 11/08/2011 for the course BSC 2011C taught by Professor Klowden/crampton during the Fall '11 term at University of Central Florida.

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Lecture 08 Outline Chapter 19 - Crampton Bio II Lecture 8...

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