Transcript I. Bacteria

I. Bacteria
A.
B.
C.
D.
E.
F.
G.
Introduction
Various functions/roles of bacteria
Diseases caused by bacteria
Classification of bacteria
Metabolism
Structure of bacteria
Reproduction
A. Introduction
1.
2.
3.
Thought to cause
human and animal
disease
actinomycetes,
produce antibiotics
such as streptomycin
and nocardicin;
Some live
symbiotically in the
guts of animals
(including humansecoli
Leptospira-disease in livestock
Intro. Cont.
4.
5.
6.
7.
8.
9.
Bacteria put the tang in yogurt
Put the sour in sourdough bread
break down dead organic matter
bacteria make up the base of the food web in many
ecosystems
extreme flexibility, capacity for rapid growth and
reproduction, and great age-they have been around a
very long time!
nearly 3.5 billion years old-are fossils of bacterialike organisms.
B. Functions/Roles of Bacteria
1.
2.
3.
4.
5.
6.
Nitrogen fixation
a. convert nitrogen into a usable form on the roots of plants
Recycling of nutrients
a. break down dead organic matter
Foods
a. Used in food to put the tang in yogurt and the sour in
sourdough bread
Medicines
a. produce antibiotics
Cause disease
Genetic Engineering!!!!
C. Diseases Caused by Bacteria
D. Classification of Bacteria
1.
Kingdom
a.
2.
Monera
Phylums:
a. Archaebacteria
b.
Eubacteria
3. Archaebacteria
a)
b)
c)
Known as the
extremophiles
Live in extreme
environments that
would kill other
microbes
Also know as the
ancient bacteria
4. Extreme
Thermophiles
d)
Extreme
Thermophiles
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
e)
f)
g)
Hot pots
Hydrothermal vents
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1
High temperatures
Sulfur
Thermus Aquaticus
–taq polyermase
used in PCR
Hot spring (yellow patches are mats of microbial growth)
d. Examples of Extremophiles
i.
Thermophiles
1)
2)
3)
4)
high temperature (80 degrees to
105 degrees C) for growth
Sulfur-oxidizers grow at low pH
(less than pH 2) because they
acidify their own environment
by oxidizing S (sulfur) to H2SO4
(sulfuric acid).
inhabitants of hot, sulfur-rich
environments associated with
volcanism, such as hot springs,
geysers etc.
Yellowstone National Park, and
thermal vents ("smokers") and
cracks in the ocean floor
examples
e. Extreme Methanogens
Methanogens live
a)
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
marshes
lake sediments
digestive tracts
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
b)
mammals (cows)
sewage disposal
plants.
Natural Gas
e. Extreme Methanogens
c)
d)
e)
methanogens produce
methane (CH4)
metabolism created most
the natural gas (fossil fuel)
reserves that are tapped as
energy sources for
domestic or industrial use
can be exploited to produce
energy from waste
materials
f. Extreme Halophiles
locations
1)
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Dead Sea
Great Salt Lake
Evaporating Ponds
2)
Salt loving
3)
Halobacterium halobium
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Purple membrane
bacteriorhodopsin
heterotrophs
f. Extreme Halophiles
1)
Halobacterium
halobium, prevalent in
the Great Salt Lake,
adapts to the high-salt
environment by the
development of
"purple membrane",
2)
3)
4)
pigment in the plasma
membrane rhodopsin
called bacteriorhodopsin
reacts with light in a way
that forms a proton
gradient on the membrane
allowing the synthesis of
ATP.
Absorb green light and
reflect red and blue
Evolutionary link to
photosynthesis
Eubacteria-true
bacteria
E. Metabolism
1.
2.
3.
Obligate aerobes
a.
Require oxygen
b.
Mycobacterium
tubberculosis

tuberculosis
Obligate anaerobes
a.
Killed by oxygen
b.
Treponema pallidium

Syphilis
c.
Clostridium botulinum

Botulism
Both with or without oxygen
(facultative)
a.
cellular respiration
b.
fermentation

Syphilis

Botulism
E. Metabolism
4.
Heterotrophs
a)
b)
Use organic molecules as food source
Parasites
 Obtain nutrients from living organisms
a)
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
Saprophytes
Feed on dead organism
organic wastes
Recyclers or decomposers-contain
cellulase enzymes
E. Metabolism
Photosynthetic Autotrophs
5.
a.
Use Sunlight to make food

b.
c.
d.
Live in Ponds, streams, moist areas of land
Cyanobacteria
Blue-green, red or yellow
Chains of independent cells
Eubacteria Chemosynthetic Autotrophs
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Make food from chemosynthesis
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Sulfur
Nitrogen
Convert unusable atmospheric nitrogen into nitrogen containing
compounds plant can use.
nitrogen fixation by bacteria such as Rhizobium
Convert sulfur to sulfuric acid
Sulfur-oxidizers grow at low pH (less than pH 2) because they acidify their
own environment by oxidizing S (sulfur) to H2SO4 (sulfuric acid).
Why Yellowstone stinks!
F. Bacterial Structure
1.
2.
Very small cell
Lack membrane bound organelles

3.
Lack nuclear membrane
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4.
5.
Ribosomes
DNA circular
Nucleoid
Biochemical processes in cytoplasm
Plasmids –loops of DNA
Typical Bacteria Cell
Electron
Micrograph
of
E. Coli
Plamids
G. Reproduction
1.
2.
Asexual
sexual
1. Asexual
BINARY FISSION
Asexual Reproduction
a.
b.
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
c.
d.
Copies chromosome
Attach to cell’s plasma
membrane
DOUBLING THEIR
NUMBERS EVERY
20 MINUTES
**favored for genetic
engineering**
1928
1
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Fleming
discovers penicillin
the first antibiotic.
Inhibits cell wall
growth!
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