Bacteria & Viruses

1. Bacteria & Viruses SBI 3U

2. Remember - MRS. NERG • Movement • Reproduction • Sensitivity • Nutrition • Excretion • Respiration • Growth

3. 6 Kingdoms • Archaea • Eubacteria • Protista • Fungi • Plants • Animals No Viruses

6. Bacteria

9. Types of Bacteria • Coccus (cocci) - Round • Baccilus (baccili) – rod shaped • Spirochete – corkscrew shaped • Vibrios – comma shaped

11. Classification of Bacteria • Until recently classification has done on the basis of such traits as: • shape • bacilli: rod-shaped • cocci: spherical • spirilla: curved walls • ability to form spores • method of energy production (glycolysis for anaerobes, cellular respiration for aerobes • nutritional requirements • reaction to the Gram stain. • The Gram stain is named after the 19th century Danish bacteriologist who developed it. • The bacterial cells are first stained with a purple dye called crystal violet. • Then the preparation is treated with alcohol or acetone. • This washes the stain out of gram-negative cells. • To see them now requires the use of a counterstain of a different color (e.g., the pink of safranin). • Bacteria that are not decolorized by the alcohol/acetone wash are gram-positive.

12. Viruses • Viruses can’t metabolize nutrients, produce and excrete wastes, move around on their own, or even reproduce unless they are inside another organism’s cells. • They aren’t even cells.

15. Role of viruses… • “Viruses have played key roles in shaping the history of life on our planet by shuffling and redistributing genes in and among organisms and by causing diseases in animals and plants. Viruses have been the culprits in many human diseases, including smallpox, flu, AIDS, certain types of cancer, and the ever-present common cold.” http://www.microbeworld.org/microbes/virus/

16. When viruses come into contact with host cells, they trigger the cells to engulf them, or fuse themselves to the cell membrane so they can release their DNA into the cell.

17. Viruses “hijack” the cell

18. “Once inside a host cell, viruses take over its machinery to reproduce. • Viruses override the host cell’s normal functioning with their own set of instructions that shut down production of host proteins and direct the cell to produce viral proteins to make new virus particles. http://www.microbeworld.org/microbes/virus/

21. Lytic Cycle • Attachment • Penetration • Synthesis • Assembly • Lysis • Release Mnemonic: All Pirates Sail Around Looking for Riches

24. All Viruses are pathogenic • There are NO nice viruses……… • All viruses cause disease.

25. Diseases Caused by Virus To Human

27. http://library.thinkquest.org/23054/gather/index.shtml