1. BACTERIA (Ch. 24) AND VIRUSES (Ch. 25)

2. BACTERIA: Simplest & most primitive life forms (fossils from 3.5 bya)

3. 2 Kingdoms: ArchaebacteriaEubacteria

4. Archaebacteria: “ancient bacteria” live in extreme environments

5. Thermoacidophile Thermoacidophile: thrives in hot, acidicenvironments

6. Halophile Halophile: thrives in saltyenvironments

7. Methanogen Methanogen: thrives in methane-richenvironment

8. Eubacteria “true bacteria” live in “normal” environments

9. Simple Structure: PROKARYOTE no nucleus or membrane-boundorganelles

10. Chromosome is in one loop, not in pairs Chromosome # 1

11. Have ribosomes; needed to make structural proteins and enzymes

12. Cell Wall: Some cell walls have a thick layer of peptidoglycan, a carbohydrate

13. Gram Positive: stains purple; stain is held by peptididoglyganlayer

14. Gram Positive

15. Gram Negative Gram Negative: Stains pink; stain resistant since there is a layer over the peptididoglycanlayer

16. Gram Negative

17. Cell Parts:

18. Classified by Shapes 1.Bacillus: ovals

19. 2.Coccus: round

20. 3.Spirillus: wavy or bent or bent

21. Configurations: Diplo: in pairs Diplococcus

22. Strepto: in chains Streptococcus Streptobacillus

23. Staphylo: in clusters

24. Reproduction: Binary Fission

25. Rapid life cycle since there is no mitosis

26. Some genetic recombination by three different methods:

27. 1.Conjugation Two bacteria join up at the pili (conjugation bridge) and exchange a small loop of DNA that has detached from the main DNA (plasmid)

28. The plasmid is incor- porated into the DNA of the receiving cells conjugation conjugation bridge bridge

29. Transformation: Substitutes new DNA for a similar fragment in its original DNASubstitutes new DNA for a similar fragment in its original DNA

30. Transformation:

31. Transduction: A virus obtains a piece of DNA from host bacteriumA virus obtains a piece of DNA from host bacterium Virus transfers DNA to new cell that it infectsVirus transfers DNA to new cell that it infects

32. Transduction:

33. NUTRITION:AUTOTROPHIC by photosynthesis or chemosynthesis

34. Heterotrophic: many are saprophytic-- eat dead stuff

35. METABOLISM/ RESPIRATION: Obligate Aerobe Must have Oxygen to survive

36. Obligate Anaerobe: Can only survive in the absence of oxygen

37. Facultative Anaerobe: Can live with or withoutoxygen

38. Effects on Humans: DecomposersDecomposers Food & DrugFood & Drug industries industries

39. Clean up toxicClean up toxic waste naturally NaturalNaturalpesticides

40. Nitrogen fixation fixation Extract nitrogen from the environment for plants to use

41. Cause diseases by releasing toxins into host organism

42. Exotoxins: Produced by Gram positive cellsProduced by Gram positive cells Toxins constantly produced and steadily released by cellToxins constantly produced and steadily released by cell Protein-based toxinsProtein-based toxins

43. Endotoxins: Produced by Gram- negative cellsProduced by Gram- negative cells Toxins released when bacterium diesToxins released when bacterium dies Lipid or carbohydrate based toxinsLipid or carbohydrate based toxins

44. How can we control bacteria? Antibiotics! Wash hands! Good sanitation!Pasteurization Good sanitation!Pasteurization Immunizations! Safe sex!!! Immunizations! Safe sex!!!

45. Problem: ANTIBIOTIC RESISTANCE From overuse (antibiotics only From overuse (antibiotics only work on gram-positive work on gram-positive bacteria; doctors have bacteria; doctors have prescribed for any bacteria prescribed for any bacteria and also viruses and also viruses Patients don’t take all Patients don’t take all prescribed medication, as prescribed medication, as directed directed

46. Bacterial mutations occur that also result in resistance Bacterial mutations occur that also result in resistance Example: Tuberculosis used to respond to used to respond to penicillin but now it penicillin but now it doesn’t doesn’t