Powerpoint for AP Biology Chapter 19 on Viruses

1. VIRUSES Chapter 19

5. Fig. 19-2 RESULTS 1 2 3 Extracted sap from tobacco plant with tobacco mosaic disease Passed sap through a porcelain filter known to trap bacteria Rubbed filtered sap on healthy tobacco plants 4 Healthy plants became infected

7. Fig. 19-3 RNA Capsomere Capsomere of capsid DNA Glycoprotein 18  250 nm 70–90 nm (diameter) Glycoproteins 80–200 nm (diameter) 80  225 nm Membranous envelope RNA Capsid Head DNA Tail sheath Tail fiber 50 nm 50 nm 50 nm 20 nm (a) Tobacco mosaic virus (b) Adenoviruses (c) Influenza viruses (d) Bacteriophage T4

10. Transcription and manufacture of capsid proteins Self-assembly of new virus particles and their exit from the cell Entry and uncoating Fig. 19-4 VIRUS 1 2 3 DNA Capsid 4 Replication HOST CELL Viral DNA mRNA Capsid proteins Viral DNA

13. Fig. 19-5-5 Phage assembly Head Tail Tail fibers Assembly Release Synthesis of viral genomes and proteins Entry of phage DNA and degradation of host DNA Attachment 1 2 4 5 3

15. Fig. 19-6 Phage DNA Phage The phage injects its DNA. Bacterial chromosome Phage DNA circularizes. Daughter cell with prophage Occasionally, a prophage exits the bacterial chromosome, initiating a lytic cycle. Cell divisions produce population of bacteria infected with the prophage. The cell lyses, releasing phages. Lytic cycle Lytic cycle is induced or Lysogenic cycle is entered Lysogenic cycle Prophage The bacterium reproduces, copying the prophage and transmitting it to daughter cells. Phage DNA integrates into the bacterial chromosome, becoming a prophage. New phage DNA and proteins are synthesized and assembled into phages.

17. Fig. 19-7 Capsid RNA Envelope (with glycoproteins) Capsid and viral genome enter the cell HOST CELL Viral genome (RNA) Template mRNA ER Glyco- proteins Capsid proteins Copy of genome (RNA) New virus

18. Table 19-1a

19. Table 19-1b

21. Fig. 19-8a Glycoprotein Reverse transcriptase HIV RNA (two identical strands) Capsid Viral envelope HOST CELL Reverse transcriptase Viral RNA RNA-DNA hybrid DNA NUCLEUS Provirus Chromosomal DNA RNA genome for the next viral generation mRNA New virus

22. Fig. 19-8b HIV Membrane of white blood cell HIV entering a cell 0.25 µm New HIV leaving a cell

24. mimivirus Which came first, the cell or the mimivirus? The virus was first isolated in 1992 from amoebae growing in a water tower.

28. Fig. 19-9 (a) The 1918 flu pandemic (b) Influenza A H5N1 virus (c) Vaccinating ducks 0.5 µm

30. Fig. 19-10

32. Viroids in Plants

33. Misfolding of proteins to form prions Fig. 19-11 Prion Normal protein Original prion New prion Aggregates of prions

34. Scrapie in sheep