BACTERIA_AND_VIRUSES_Jan_21 - o Many cell divisions Many...

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BACTERIA AND VIRUSES Viruses, though not considered alive, are often grouped with microscopic organisms under the general term “microbes” Viruses are parasites that can reproduce only in cells the host cell provides most of the components for replicating, transcribing, and translating the viral nucleic acid. Lytic cycle: results in the lysus (breaking open) of the host cell and releasing the viruses produced in the cell. Lsogenic cycle: viral DNA replication occurs without destroying the host cell Phage Reproductive Cycle (DNA) Possibility One o Phage attaches to cell o Phage injects dna o New phage Dna and proteins are synthesized o Phages assemble o Cell lysus releasing phages Phage Reproduction Cycle (DNA) Possibility Two o Phage attaches to cell o Phage injects DNA o Phage DNA inserts into the bacterial chromosome by recombination o Lysogenic bacterium normally replicating the pro-phage at each cell divide
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Unformatted text preview: o Many cell divisions Many animal viruses contain RNA rather tan DNA RNA viruses include: cold, measles, mumps, AIDS, Polio RNA Reproductive Cycle o Entry o Uncoating o Viral RNA (genome) o RNA synthesizes by viral enzyme o Protein synthesis or RNA synthesis o Assembly o Exit Emerging viruses: viruses that appear suddenly or are new to medical history Processes Contributing to emerging viruses o Mutating or existing viruses o Spread of one host species to another species (humans to animals, or animals to human) o Viroid: small, circular RNA molecules that infect plans Do not encode proteins but can replicate in host plant cells using cellular enzymes o Prions: cause degeneration brain disease in various animal species Enters the cell containing normal protein molecules and converts them into mis-folded protein versions...
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This note was uploaded on 12/21/2011 for the course BIO 202 taught by Professor Brooks during the Fall '11 term at UCSB.

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BACTERIA_AND_VIRUSES_Jan_21 - o Many cell divisions Many...

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