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Viruses
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Obligate intracellular parasites; requires a host cell to grow and replicate
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All viruses contain:
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Aremuch smaller than bacterial cells
DNA or RNA; protein coat (capsid)
Some are enclosed by an envelope (phospholipid bilayer)
Some have spikes (glycoproteins that bind to host)
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Specificity
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Viruses that infect only a specific type of cell in one host
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Host range
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Spectrum of host viruses can infect determined by the host attachment site
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Viral Species
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A group of viruses sharing the same genetic information and ecological niche (host)
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Viruses must be grown
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In living cells
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Bacteriophages
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(viruses that infect bacteria) form clearings (plaques) on a lawn of bacteria
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Animal viruses
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May be grown in living animals or in embryonated eggs
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Cell culture
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Animal and plant viruses are grown in this
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Primary cell line
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From human adult tissue; but die out quickly
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Diploid cell lines
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From embryonic tissue; lasts about 100 generations
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Continuous cell lines
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Immortal; from cancer tissue
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Cytopathic effects
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Physical changes to viral infected cells (rounded unattached)
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PCR
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Polymerase chain reaction - amplifies specific genes
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Multiplication of bacteriophages
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Attachment, penetration, biosynthesis, maturation, release, lytic cycle
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