Download The Wonderful World of Microbes

The Wonderful
World of Microbes
Bacteria & Viruses
Chapter 19
By the end of this lesson, you
wil be able to:
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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
Two Prokaryotic Domains:
1)
Bacteria - members of Eubacteria Kingdom
o
o
2)
Live everywhere - saltwater, freshwater, land, inside
other organisms
Surrounded by a cell wall with peptidoglycan
Archaea - members of the Archaebacteria Kingdom
o
o
o
DNA more similar to eukaryotes (eukaryotic ancestors)
No peptidoglycan in their cell walls
Live in harsh environments o
o
o
Oxygen free - methanogens
Hot - thermophiles
Salty - halophiles
Basic Bacterial Structure:
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But there are many different
types…
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Prokaryotic Diversity:
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Shape
Spiral-shaped
 Rod-shaped
 Spherical-shaped
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Prokaryotic Diversity:
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Cell Walls
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2 types of cell walls
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Gram positive - Thick
wall of peptidoglycan
holds the stain
Gram negative - Inner,
thin peptidoglycan does
not hold the stain
Prokaryotic Diversity:
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Movement Types
1) No movement
2) Flagella methods
3) Spiral forward
4) Slime secretions
Prokaryotic Diversity:
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Energy Obtainment
1)
Autotrophs
1)
2)
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2)
Photoautotroph
Chemoautotroph
Heterotrophs
1)
2)
Chemoheterotrophs
Photoheterotrophs
Prokaryotic Diversity:
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Energy Release
1)
Obligate aerobe
1)
2)
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Obligate anaerobe
1)
3)
Poisoned by Oxygen
Facultative anaerobe
1)
E. coli
Require Oxygen
Survive either with or
without Oxygen
Prokaryotic Diversity
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Growth and
Reproduction Methods
Binary Fission
2) Conjugation
3) Spore formation
1)
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Conjugation & Spore formation:
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Their role in our world:
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Producers - base of food
web
Decomposers - recycle
nutrients
Nitrogen fixers - change
gaseous Nitrogen (N2)
into a form that plants can
use and take up
Human Uses for bacteria
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Sewage and petroleum
(oil) breakdown
Produce fertilizers
Make drugs
Produce vitamins in our
intestines
Make foods and
beverages
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What do you see? What do you
think this is???
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Does this view help? How do
you think it works?
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Homework:
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19-1 worksheet
Read & vocab on 19-2
The Other Microbes....
VIRUSES
But are they are really????
What does it mean to be a
microbe?
Viral Basics:
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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
Tobacco Mosaic Virus
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Well known Plant virus
Uses the tobacco plant as
its host
Studied in 1935, by
Wendell Stanley
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Viral Structure
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Lysogenic Infection
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Lytic Infections
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Retrovirus
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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
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AIDS Virus
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So should they be considered
living????
Characteristic
Reproduce?
Contain nucleic acid?
Grow and develop?
Use energy?
Respond to environment?
Change over time???
Yes or No???
Diseases & Humans
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Pathogens - disease causing; bacteria and
viruses
HOW DO THEY DO THIS???
1)
2)
Viruses: Attack and destroy body cells
Bacteria:
1)
2)
Damages cells and tissues by breaking them down for
food
Release toxins into the body
What do we do???
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Viruses - AIDS, cold, hepatitus, West Nile, flu…
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Vaccines
Anitviral drugs
Bacteria - Tuberculosis, Strep throat, tooth decay…
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Vaccines
Antibiotics
Disinfectants, sterilization or food processing
Viruses for thought….
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Do you think they evolved before or after cells?
Why?
How do they affect life?
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Viroids - Disease causing RNA molecules
Prions - Disease causing proteins