1. The Wonderful World of Microbes
Bacteria & Viruses
Chapter 19

2. By the end of this lesson, you wil be able to:
Distinguish between the two Prokaryote Domains
Describe the diversity among prokaryotes
Explain the influence bacteria have on our world
Describe viral composition and diversity
Explain the two viral life cycles
Answer if viruses should be considered living or not

3. Two Prokaryotic Domains:
Bacteria - members of Eubacteria Kingdom
Live everywhere - saltwater, freshwater, land, inside other organisms
Surrounded by a cell wall with peptidoglycan
Archaea - members of the Archaebacteria Kingdom
DNA more similar to eukaryotes (eukaryotic ancestors)
No peptidoglycan in their cell walls
Live in harsh environments -
Oxygen free - methanogens
Hot - thermophiles
Salty - halophiles

4. Basic Bacterial Structure:

5. But there are many different types…

6. Prokaryotic Diversity:
Shape
Spiral-shaped
Rod-shaped
Spherical-shaped

7. Prokaryotic Diversity:
Cell Walls
2 types of cell walls
Gram positive - Thick wall of peptidoglycan holds the stain
Gram negative - Inner, thin peptidoglycan does not hold the stain

8. Prokaryotic Diversity:
Movement Types
1) No movement
2) Flagella methods
3) Spiral forward
4) Slime secretions

9. Prokaryotic Diversity:
Energy Obtainment
Autotrophs
Photoautotroph
Chemoautotroph
Heterotrophs
Chemoheterotrophs
Photoheterotrophs

10. Prokaryotic Diversity:
Energy Release
Obligate aerobe
Require Oxygen
Obligate anaerobe
Poisoned by Oxygen
Facultative anaerobe
Survive either with or without Oxygen
E. coli

11. Prokaryotic Diversity
Growth and Reproduction Methods
Binary Fission
Conjugation
Spore formation

12. Conjugation & Spore formation:

13. Their role in our world:
Producers - base of food web
Decomposers - recycle nutrients
Nitrogen fixers - change gaseous Nitrogen (N2) into a form that plants can use and take up

14. Human Uses for bacteria
Sewage and petroleum (oil) breakdown
Produce fertilizers
Make drugs
Produce vitamins in our intestines
Make foods and beverages

15. What do you see? What do you think this is???

16. Does this view help? How do you think it works?

17. Homework:
19-1 worksheet
Read & vocab on 19-2

18. The Other Microbes.... VIRUSES
But are they are really????
What does it mean to be a microbe?

19. Viral Basics: Disease-causing particles
Contain nucleic acids (DNA or RNA) surrounded by a protein coat (capsid)
“Trick”s host cell in allowing it to bind to it, invade, and replicate
Uses the host cell’s system to replicate and then destroys it

20. Tobacco Mosaic Virus Well known Plant virus
Uses the tobacco plant as its host
Studied in 1935, by Wendell Stanley

21. Viral Structure

22. Lysogenic Infection

23. Lytic Infections

24. Retrovirus Contain RNA instead of DNA
Remain dormant for a length of time
Their RNA is copied into DNA in the host cell
Responsible for AIDS and some types of cancer

25. AIDS Virus

26. So should they be considered living????
Characteristic
Yes or No???
Reproduce?
Contain nucleic acid?
Grow and develop?
Use energy?
Respond to environment?
Change over time???

27. Diseases & Humans Pathogens - disease causing; bacteria and viruses
HOW DO THEY DO THIS???
Viruses: Attack and destroy body cells
Bacteria:
Damages cells and tissues by breaking them down for food
Release toxins into the body

28. What do we do??? Viruses - AIDS, cold, hepatitus, West Nile, flu…
Vaccines
Anitviral drugs
Bacteria - Tuberculosis, Strep throat, tooth decay…
Antibiotics
Disinfectants, sterilization or food processing

29. Viruses for thought….
Do you think they evolved before or after cells? Why?
How do they affect life?
Viroids - Disease causing RNA molecules
Prions - Disease causing proteins