1. VIRUSES CHAPTER 18 Part 1

2. Characteristics non-living particlesnon-living particles invade living cellsinvade living cells pathogenic - named after the disease they cause or organ they infectpathogenic - named after the disease they cause or organ they infect smallest of all organismssmallest of all organisms T-4 Virus - infects E. coli

4. VIRUS - an obligate intracellular parasite INFECTIOUS MONONUCLEOSIS

5. Origin of Viruses Viruses may have originated from host cellsViruses may have originated from host cells 1935 - first seen by an electron microscope1935 - first seen by an electron microscope Tobacco mosaic virus - first virus discovered - 1886Tobacco mosaic virus - first virus discovered - 1886 Wendell Stanley (1904 - 1971) first isolated TMV in 1935.

6. 1886 - “Living Fluid Infectant” - the virus passed through filters that held bacteria.

7. Viral Structure Inner core - contains viral DNA or RNA (never both) Capsid - outer coat of protein Envelope - outer layer on larger viruses

8. http://glencoe.mcgraw- hill.com/olcweb/cgi/pluginpop.cgi?it =mov::196::240::/sites/dl/free/00788 02849/181977/e21_1int.mov Click on the link above

9. Various Shapes of Viruses

10. Viral Replication Lytic Cycle 1. Attachment1. Attachment 2. Injection2. Injection 3. Replication3. Replication 4. Assembly4. Assembly 5. Lysis5. Lysis

11. LYTICLYTIC LYSOGENICLYSOGENIC

12. LYSOGENIC CYCLE 1. Attachment 2. Injection 3.Viral DNA integration (provirus) 4. Cell division 5. Replication 6. Assembly 7. Lysis

13. VIRUSES CHAPTER 18 Part 2

14. Edward Jenner - discovered a vaccine for smallpox

15. Smallpox Variola (Major & Minor) First virus to be studied in detail Edward Jenner - 1798 First vaccine - cowpox virus (vaccinia virus)

16. Child with smallpox

17. Last case of smallpox (Ali Maow of Merka, Somalia, contracted smallpox in 1977 at the age of 23. His was the last known case of smallpox in the world.)

18. Icosahedral Virus (many sides) Wart virus Polio - Naked, small, icosahedral virus

19. Enveloped Virus INFLUENZA VIRUS

20. Children with measles (uncommon today)

21. BACTERIOPHAGE E-Coli Bacteria

22. Attachment of a phage to the cell wall of E-Coli

23. Temperate vs. Virulent Viruses

24. HERPES ZOSTER (“Shingles”)

25. HERPES VIRUS HERPES

26. Retroviruses RNA virusesRNA viruses Reverse transcriptase - makes DNA from its RNAReverse transcriptase - makes DNA from its RNA Includes HIV, polio & some cancersIncludes HIV, polio & some cancers HIV

27. Retrovirus Cycle

28. HIV / AIDS

30. Louis Pasteur - discovered a vaccine for rabies

32. Animal Rabies in U. S. 1999