UAB BY 123 Exam 4 Latest Questions With Passed Solutions!!

Virus - infectious particle consisting of genes packaged in a protein coat non-living obligate intracellular parasite A Virus is not living - True Viruses can't produce or carry out metabolism outside of a host cell - True Where do viruses reproduce? - In living cells Viruses=parasites - Obligate parasites - require a host cell for replication All living organisms have viruses: - prokaryotes and all varieties of eukaryotes Bacterial viruses - Bacteriophage; phages Virus Sizes - Small can't be seen with light microscope much smaller than bacteria or eukaryotic cell Virus structure can be studied with....? - Electron microscopes Capsid - protein shell that surrounds genome What is a capsid made up of? - Capsomeres; they dictate everythingViral envelope - membrane that surrounds capsid; comes from modified host membrane (after infection of host) contain a combination of viral and host cell molecules Capsid shapes - helical or polyhedral; or sometimes both Viral genetic material is.... - diverse RNA is _________ the genetic material in a cellular organism - NEVER Virus have ___________ that help them infect hosts - accessory structures A viral envelope can be used to disguise a virus to look normal to be able to invade immune system - True Bacteriophage; phages - viruses specific to bacteria; best understood of viruses 2 reproductive mechanisms of phages - lytic cycle lysogenic cycle Lytic cycle - host cell is lysed/destroyed Lysogenic cycle - become part of cell Virulent viruses - undergo lytic cycle; take over hos cell and replicate; typically destroy host cellTemperate viruses - undergo lysogenic cycle; virus genes remain dormant; can then undergo lytic cycle (destroy cell) 5 Stages Lytic Cycle - 1. Attachment 2. Penetration 3 and 4: Breakdown of host cell and self assembly 5: Release 1. Attachment Stage - Virus attaches to outside of host cell 2. Penetration Stage - Genetic material is injected into cell