Download Bacteria

Domain Bacteria
Domain Archaea
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Domain Archaea
Prokaryotes
Single-celled
Most live in extreme
environments
(different species may
live in extreme cold,
hot, salty, acidic or
other extreme
conditions)
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Domain Bacteria
Prokaryotes
Single-celled
Live everywhere
(except extreme
environments)
Kingdom: Bacteria
Prokaryotic
Cell Walls made of
peptidoglycan
Bacterial DNA is not
associated with histone
proteins (“naked
DNA”)
Ribosome activity is
inhibited by the
antibiotics streptomycin
& chloramphenicol
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By their mode of
nutrition, or how they
metabolize resources
(what they eat)
By their ability (or
not) to produce
endospores
By their means of
motility
By their shape
By their cell walls
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Cyanobacteria
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Clostridium—causes
tetanus
Some bacteria are
photoautotrophs—
capable of
photosynthesis
Some are
chemoautotrophs
Some are
heterotrophs—these
may be decomposers,
parasites, or
pathogens.
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Some bacteria (mostly
Gram+) have the ability to
produce endospores.
These are resistant bodies
that contain the genetic
material and a small
amount of cytoplasm
surrounded by a cell wall.
Endospore formation
usually starts with a lack
Endospores can lie dormant for
of nutrients.
centuries, perhaps even millions of
years!
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Most bacteria are classified into one of three
shapes:
Cocci—spherical
shaped
Cocci
Bacilli
Spirilla
Spirilla
Bacilli—rod
shaped
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Gram-positive cell walls
have a layer of
peptidoglycan outside of
the cell membrane.
Gram-negative cell walls
have a layer of
peptidoglycan in between
two layers of cell
membranes. (The outer
layer is made of
lipopolysaccharides—
LPS)
Peptidoglycan is a
combination of a
monosaccharide and
amino acid chains.
Cyanobacteria:
Photosynthetic
Have chlorophyll to
capture light
energy
Split H2O and release
O2
They may also
contain accessory
pigments called
phycobilins
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Chemosynthetic
Bacteria
Autotrophs
(chemoautotrophs)
Make their own food
from inorganic
compounds such as
nitrogen, sulfur, or
hydrogen.
Some are called
nitrifying bacteria—
these convert nitrite
(NO2-) to nitrate (NO3-)
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Nitrogen-fixing Bacteria:
Heterotrophs that fix nitrogen.
They can convert N2 gas into
nitrate (NO3- ).This form of
Nitrogen can be taken up by
plants and other organisms.
Many of these have mutualistic
relationships with plants—both
the plant and the bacteria
benefit from an interdependent
relationship.
The bacteria live in nodules,
specialized structures in plant
roots.
Nitrogen-fixing bacteria live in
the roots of Legumes such as
soybeans and alfalfa.
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Spirochetes
Coiled bacteria that
move with a
corkscrew motion.
Their flagella are
internal, positioned
within the layers of
the cell wall.
A spirochete bacteria causes Lyme
Disease
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These differ from other
bacteria in several
important ways:
Archaea cell walls
contain various
polysaccharides, but not
peptidoglycan (as in
bacteria)
Archaea cell
membranes contain
different types of
phospholipids—(the
hydrocarbon chains are
branched)
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The DNA of both archaea
and eukaryotes are
associated with histone
proteins.
Bacterial DNA is
“naked”—it does not have
histones.
Ribosomal activity in both
archaea and eukaryotes
are not inhibited by the
antibiotics streptomycin
and chloramphenicol.
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Methanogens
These are obligate
anaerobes (cannot
survive in O2)
They produce methane
(CH4) as a by-product of
obtaining energy
They live in mud,
swamps, and the guts of
cows, humans, termites,
and other animals.
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Extremophiles:
Halophiles (“salt
lovers”) live in
environments with high
salt contents, such as
the Great Salt Lake and
the Dead Sea
Thermophiles (“heat
lovers”) live in hot (6080oC) environments
such as hot springs or
geysers. Most are
sulfur-bases
chemoautotrophs.
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In the deepest parts of
the ocean, where it is
extremely cold and
dark, there is an entire
ecosystem based on
chemosynthetic
archaea bacteria.
These thrive on the
H2S gases from
hydrothermal vents.
Other organisms feed
on the bacteria.
Yeti Crab feed on bacteria by filtering
them with their feathery gills.