Presentation on theme: "The Wonderful World of Microbes"— Presentation transcript:
1 The Wonderful World of Microbes Bacteria & VirusesChapter 19
2 By the end of this lesson, you wil be able to: Distinguish between the two Prokaryote DomainsDescribe the diversity among prokaryotesExplain the influence bacteria have on our worldDescribe viral composition and diversityExplain the two viral life cyclesAnswer if viruses should be considered living or not
3 Two Prokaryotic Domains: Bacteria - members of Eubacteria KingdomLive everywhere - saltwater, freshwater, land, inside other organismsSurrounded by a cell wall with peptidoglycanArchaea - members of the Archaebacteria KingdomDNA more similar to eukaryotes (eukaryotic ancestors)No peptidoglycan in their cell wallsLive in harsh environments -Oxygen free - methanogensHot - thermophilesSalty - halophiles
18 The Other Microbes.... VIRUSES But are they are really????What does it mean to be a microbe?
19 Viral Basics: Disease-causing particles Contain nucleic acids (DNA or RNA) surrounded by a protein coat (capsid)“Trick”s host cell in allowing it to bind to it, invade, and replicateUses the host cell’s system to replicate and then destroys it
20 Tobacco Mosaic Virus Well known Plant virus Uses the tobacco plant as its hostStudied in 1935, by Wendell Stanley
26 So should they be considered living???? CharacteristicYes or No???Reproduce?Contain nucleic acid?Grow and develop?Use energy?Respond to environment?Change over time???
27 Diseases & Humans Pathogens - disease causing; bacteria and viruses HOW DO THEY DO THIS???Viruses: Attack and destroy body cellsBacteria:Damages cells and tissues by breaking them down for foodRelease toxins into the body
28 What do we do??? Viruses - AIDS, cold, hepatitus, West Nile, flu… VaccinesAnitviral drugsBacteria - Tuberculosis, Strep throat, tooth decay…AntibioticsDisinfectants, sterilization or food processing
29 Viruses for thought….Do you think they evolved before or after cells? Why?How do they affect life?Viroids - Disease causing RNA moleculesPrions - Disease causing proteins