Genetics of Viruses and Prokaryotes - Genetics of Viruses...

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Genetics of Viruses and Prokaryotes 13.1 Viruses aren’t cells -nucleic acid + few proteins = virus -no metabolic functions, and no regulation of substances in and out Viruses reproduce only w/ help of living cells -must infect a host cell to reproduce -virion = virus particle -DNA or RNA covered w/ protein coat (capsid) -antibiotics for viral infection? - genome of DNA or RNA -nucleic acid is single or double stranded - membrane or no membrane Bacteriophage by lytic cycle or lysogenic cycle -viruses that only reproduce by lytic cycle is called virulent virus - viruses take control of molecular machinery -promoter sequence to attract RNA polymerase to be transcribed, viral genes code for proteins that shut down host transcription and stimulate genome replication; breakdown host’s chromosomes providing source of nucleotides -late genes code for viral capsid and lyseing of cell membrane - about ½ hr to complete -possible for 2 viruses to infect same cell, allows for crossing over and new strains of viruses Lysogenic Cycle - don’t always result in lysis of host cell - -bacteria harboring viral genome are lysogenic bacteria and viruses inside called temperate viruses - lysogenic bacteria contain prophages : molecules of phage DNA in bacterial chromosome - can be replicated to several genetations of bacteria - activation leads to lytic cycle Phage Therepy - can use phages to treat bacterial infections Animal Viruses -anthropod viruses only infect the bitten one, anthropod acts as a vector -3 ways to enter -naked viron (no membrane): taken up by endocytosis, attacks once free
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This note was uploaded on 09/15/2009 for the course MOLECULAR 20A taught by Professor Dalbey during the Winter '09 term at University of California, Santa Cruz.

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Genetics of Viruses and Prokaryotes - Genetics of Viruses...

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