1. Bacteria, Viruses, Prions, and Protists

2. Bacteria Unicellular or Multicellular? Prokaryotic or Eukaryotic?
Cells Walls?

3. Bacteria
Unicellular
Prokaryotes
Cells walls containing peptidoglycan

4. Bacteria Extremely Abundant
Cover nearly every square centimeter of Earth

5. What are the differences between eubacteria and archaebacteria?

6. Eubacteria versus Archaebacteria
Cell walls of Eubacteria have peptidoglycans while those of Archaebacteria do not.
DNA sequences of archaebacteria is more similar to that of eukaryotes than to the DNA of eubacteria
Archaebacteria often live in very extreme environments (hot springs, digestive tracts, Great Salt Lake, etc.)

7. Bacterial Shapes Bacilli: rod shaped Cocci: spherical
Spirilla: spiral, corkscrew

8. Cell Walls
Gram positive: stain violet due to thick peptidoglycan walls
Gram negative: stain pink/red, have much thinner walls inside lipid layer

9. Metabolism Heterotrophs:
Chemoheterotrophs: must take in organic molecules and a supply of carbon
Photoheterotrophs: are photosynthetic but also need to take in organic molecules for carbon source

10. Metabolism Photoautotrophs: use light energy to make carbon compounds
Chemoautotrophs: use energy from chemical reactions to make carbon compounds
Where might each type of bacteria be found?

11. Binary Fission
When a bacteria grows so that it has doubled in size, it replicates its DNA and divides in half
Is this sexual or asexual?
Identical or different daughter cells?

12. Conjugation Some bacteria are able to exchange genetic information
A hollow bridge forms between two bacteria and genes move from one cell to the other
Increases genetic diversity of a population

13. Conjugation

14. Spore Formation
Spores are formed when the bacteria produces a thick internal wall that encloses the DNA and part of the cytoplasm
Why do you think this would be beneficial for bacteria?

15. Spore Formation Occurs when conditions are unfavorable for growth
Can remain dormant for years until conditions improve

16. Spore Formation

17. What are some benefits of bacteria?

18. Benefits of Bacteria Some are producers that undergo photosynthesis
Some are decomposers that break down dead matter to recycle the nutrients
Some convert nitrogen gas to a form that can be used by plants (nitrogen fixation)

19. What are some dangers of bacteria?

20. Dangers of Bacteria Break down cells and tissues for food
Example: Tuberculosis (destroys lung tissue)
Release toxins (poisons) that travel through the body
Example: Streptococcus releases toxins into the blood stream causes strep throat and scarlet fever

21. Vaccines
A vaccine is a preparation of weakened or killed pathogens that are injected into the body
This stimulates the body to produce immunity to the disease

22. Vaccines
Why do you think we don’t vaccinate everyone for all disease we have created vaccines for?

23. Antibiotics Antibiotics block the growth and reproduction of bacteria
Used to treat bacterial infections

24. Solve the Problem
What would you do to find out what causes the tobacco leaves to be diseased?

25. Viruses
A virus is a core of DNA or RNA surrounded by a protein coat (capsid)

26. Viruses They can only reproduce by infecting living cells
They enter a cell and use its cell machinery to produce more viruses

27. Retroviruses
Contain RNA as genetic information instead of DNA

28. Would you consider viruses living?

29. Are Viruses Living? Cannot reproduce alone, must have a host cell
Do not undergo growth or development
Do not obtain or use energy
Evolve

30. Prions
Diseases such as Scrapie (in sheep) and Mad Cow Disease are not caused by bacteria or viruses. What could cause them?

31. Prions Contain only protein
Cause disease by forming protein clumps which then induce normal proteins to become Prions
The build up eventually damages nerve tissue

32. Protists
Domain?
Kingdom?
Prokaryotic or Eukaryotic?

33. Protists
Domain: Eukarya
Kingdom: Protists
Eukaryotic

34. Protists Protists are defined by what they are not.
Protists are eukaryotes that are not animals, plants, or fungi.
They were the first eukaryotic organisms on earth.

35. Types of Protists Animal-Like Protists: heterotrophs
Plant-Like Protists: produce food through photosynthesis
Fungus-Like Protists: obtain food by external digestion

36. Animal-Like Protists Heterotrophs cilliate sporozoan zooflagellate
Sarcodine (amoeba)

37. Animal-Like Protists
Malaria
African Sleeping Sickness

38. Plant-Like Protists
Carry out photosynthesis

39. Fungus-Like Protists Grow in damp, nutrient rich environments
Absorb food through cell membranes

40. Review!