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The Wonderful World of Microbes

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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

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