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Fig. 19-1

Fig. 19-1. 0.5 µm. RESULTS. Fig. 19-2. 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. 3. 1. 2. Healthy plants became infected. 4. RNA. Membranous

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Fig. 19-1

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  1. Fig. 19-1 0.5 µm

  2. RESULTS Fig. 19-2 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 3 1 2 Healthy plants became infected 4

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

  4. RNA Fig. 19-3a Capsomere of capsid 18  250 nm 20 nm (a) Tobacco mosaic virus

  5. DNA Capsomere Fig. 19-3b Glycoprotein 70–90 nm (diameter) 50 nm (b) Adenoviruses

  6. Membranous envelope RNA Capsid Fig. 19-3c Glycoproteins 80–200 nm (diameter) 50 nm (c) Influenza viruses

  7. Head DNA Fig. 19-3d Tail sheath Tail fiber 80  225 nm 50 nm (d) Bacteriophage T4

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

  9. Attachment 1 Fig. 19-5-1

  10. Attachment 1 2 Entry of phage DNA and degradation of host DNA Fig. 19-5-2

  11. Attachment 1 2 Entry of phage DNA and degradation of host DNA Fig. 19-5-3 3 Synthesis of viral genomes and proteins

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

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

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

  15. Table 19-1

  16. Table 19-1a

  17. Table 19-1b

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

  19. Viral envelope Glycoprotein Capsid RNA (two identical strands) Reverse transcriptase HIV Fig. 19-8 Membrane of white blood cell HIV HOST CELL Reverse transcriptase Viral RNA RNA-DNA hybrid 0.25 µm DNA HIV entering a cell NUCLEUS Provirus Chromosomal DNA RNA genome for the next viral generation mRNA New virus New HIV leaving a cell

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

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

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

  23. Fig. 19-9a (a) The 1918 flu pandemic

  24. Fig. 19-9b 0.5 µm (b) Influenza A H5N1 virus

  25. Fig. 19-9c (c) Vaccinating ducks

  26. Fig. 19-10

  27. Fig. 19-10a

  28. Fig. 19-10b

  29. Fig. 19-10c

  30. Fig. 19-11 Original prion Prion Aggregates of prions New prion Normal protein

  31. The phage attaches to a host cell and injects its DNA Phage DNA Fig. 19-UN1 Bacterial chromosome Prophage Lytic cycle Lysogenic cycle • Virulent or temperate phage • Destruction of host DNA • Production of new phages • Lysis of host cell causes release • of progeny phages • Temperate phage only • Genome integrates into bacterial • chromosome as prophage, which • (1) is replicated and passed on to • daughter cells and • (2) can be induced to leave the • chromosome and initiate a lytic cycle

  32. Fig. 19-UN2 B A Number of viruses Number of bacteria Time Time

  33. Fig. 19-UN3

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