1. Chapter 18.2 Viruses and Prions “Viruses and prions are smaller and less complex than bacteria; they invade cells and can alter cellular functions.”

2. Chapter 18.2 Learning Targets Illustrate the general structure of viruses. Compare and contrast the sequence of events in viral replication by the lytic cycle, the lyosgenic cycle, and retroviral replication. Discuss the structure, replication, and action of prions in relationship to causing disease.

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

5. VIRUS - an obligate intracellular parasite INFECTIOUS MONONUCLEOSIS

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

7. 1886 - “Living Fluid Infectant” - the virus passed through filters that held bacteria.

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

9. Various Shapes of Viruses

10. Viral Replication Lytic Cycle 1. Attachment 2. Injection 3. Replication 4. Assembly 5. Lysis

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

12. LYTICLYTIC LYSOGENICLYSOGENIC

13. Viruses Bozeman Biology http://www.youtube.com/watch?v=L 8oHs7G_syI 8:06 min.

14. VIRUSES CHAPTER 18 Part 2

15. Edward Jenner - discovered a vaccine for smallpox

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

17. Child with smallpox

18. 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.)

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

20. Enveloped Virus INFLUENZA VIRUS

21. Children with measles (uncommon today)

22. BACTERIOPHAGE E-Coli Bacteria

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

24. Temperate vs. Virulent Viruses

25. HERPES ZOSTER (“Shingles”)

26. HERPES VIRUS HERPES

27. Retroviruses RNA viruses Reverse transcriptase - makes DNA from its RNA Includes HIV, polio & some cancers HIV

28. Retrovirus Cycle

29. The Immune System Bozeman Biology http://www.youtube.com/watch?v=L 8oHs7G_syI 13:47 min.

30. HIV / AIDS

32. When HIV Becomes AIDS (HIV #2) http://www.youtube.com/watch?v=6 8I7JlVhuhY 3:56 min

33. Louis Pasteur - discovered a vaccine for rabies

35. Animal Rabies in U. S. 1999