BIOL 200B 1st Edition Lecture 8Chapter 35 DeuterostomesI. EchinodermsII. ChordatesIII. Vertebrate EvolutionIV. Origin of JawsV. Origin of Limbs and TetrapodsVI. Amniotic egg and mammalian placentaVII. Feathers and flightVIII. Mammals and primatesChapter 36 Viruses I. VirusII. Emerging diseasesIII. Lytic and Lysogenic CyclesIV. “life” cycle, 7 stepsV. Antiviral strategiesViruses•virus - intracellular parasite, uses host cell enzymes to replicate- consists of RNA or DNA genome within protein shell- all organisms examined are parasites by at least one virus- not made of cells- cannot metabolize on their ownThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy isbest used as a supplement to your own notes, not as a substitute.- not organisms- whether or not they are alive is an ongoing debate- lead “kind of borrowed life” Virus Morphology•tiny •host specific - specific to species they attack•made up of genome and capsid - non enveloped•genome, capsid, and envelope - envelopedEmerging Diseases - new illnesses that suddenly affect many in a host populationEx: Hantavirus, ebola, avian flu, HIV (all came from wildlife)Zoonotic pathogens switch from animal to human hostEpidemic - rapid and widespread disease outbreakPandemic - worldwide epidemic, requires human to animal transmission Ex: “Spanish flu” killed 20-50 million- strain of influenza virus was virulent (tending to cause severe disease) Viruses cause emergent and widespread diseaseInfluenza - serious threat to humans- global transport - human to animal contactRegulated by: Influenza hemoglutinin (HA) viral surface glycoprotein response for binding to host cellsViral neuraminidase (N) viral surface proteinLytic and Lysogenic cyclesLysogenic - viral DNA integrated into host genome- viruses in dormant state- viral DNA replicated each time host cell divides- cell stress activates the lytic cycleLytic - active stage, new viruses produced“Life Cycle”: 7 steps1. Attachment2. Entry into a host cell.3. Transcription of viral genomeand production andprocessing of viral proteins.4. Replication of the viralgenome.5. Assembly of a newgeneration of virions (maturevirus particles).6. Exit from infected cell(Lysis or by budding)7. Transmission new cells orhostAntiviral strategiesantivirals - drugs that interfere with viral infectionfuture strategies could include blocking replication or integration Viral Diversity•no phylogeny•grouped in 7 categories, know retroviruses and DNA virusesViral Origin Hypothesis•escaped genes•degenerated genes•RNA world-origin
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