Download The Prokaroytes

“The Kingdom Formerly
Known as Monera”
Single celled
Prokaryotic bacteria and blue-green algae
(cyanobacteria)
Life Before Oxygen
One Kingdom or two?
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Currently, some scientists prefer to divide
the Monerans into two separate
Kingdoms
– Domain Archae
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Kingdom Archaebacteria
– Domain Bacteria
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Kingdom Eubacteria
Ancient vs. True Bacteria
Differences:
 Ancient Bacteria (archaebacteria)
– their cell walls and the lipids in plasma
membranes have a different structure
– Sequences of bases in the tRNAs and rRNAs of
ancient bacteria are quite different
– React differently to antibiotics
– Able to extract nutrients from inorganic
sources (called chemoautotrophs)
Salt-loving Bacteria
(halophiles)
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Live in salt-lakes
The only prokaryotic organisms that inhabit the
Great Salt Lake and the Dead Sea
Evaporation pond on the margin of Lake Tyrrell, Australia.
The salt works salt piles can be seen in the distance.
Bacteria Of Boiling Hot Springs In
Yellowstone National Park
Heat-loving and Acid-loving
Bacteria (thermoacidophiles)
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Occupy very hot and acidic areas
Some live deep in the ocean near underwater
volcanoes and thermal vents
Others live in hot sulfur springs,
where temperatures can reach
800C and a pH as low as 2.
Castle Geyser at Yellowstone National Park
Acidophilic (acid-loving) Bacteria
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Acidophilic microbes thrive in this biofilm growing
inside an abandoned mine at Iron Mountain, Calif.
Acidic mud pots at
Yellowstone National Park
Finally…
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Some scientist feel the ancient bacteria
should be classified in a separate
kingdom.
Perhaps the ancient bacteria, the true
bacteria and the eukaryotes share a
common ancestor that was a very
early life form on Earth.
Importance of Micro-organisms
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Most are harmless
Some cause disease ex) diptheria, plague
Decompose dead animals and plants =
make raw materials of life available again
Convert and recycle essential elements
like carbon, oxygen, sulfur, and nitrogen
Some intestinal bacteria aid digestion
Recalls on California produce has experts
questioning farming practices
19:27:02 EDT Oct 10, 2006
Canadian Press: TOBI COHEN
TORONTO (CP) - The threat of E. coli and botulism
poisoning from leafy green vegetables and carrot
juice produced in California has Canadians once
again watching what they eat - and food experts
raising questions about where it comes from.
Two people in Toronto remained paralyzed Tuesday
after drinking carrot juice contaminated with
botulism, while three people have died and nearly
200 left ill after eating lettuce and spinach from the
Golden State that was laced with E. coli. ….
Recognize these?
Microbiology
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“The study of microorganisms”
Has practical applications in industry and
medicine
– Development of antibiotics
– Manufacture of dairy products (buttermilk,
cheese, yogurt, etc.)
– Experimental tools in studying biological
processes like metabolism, photosynthesis,
enzyme action, and gene action
Characteristics
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Structure
– Unicellular
– Lack a membrane-bound nucleus and
organelles (aka prokaryotic)
– Possess a single chromosome
– Possess a cell wall (protection; osmotic
balance)
– Cell wall often surrounded by a capsule
Diversity of size and shape:
Mycoplasma genitalium 0.4 µm
Haemophilus influenza 1.0 µm
Staphylococcus aureus 0.9 µm
Escherichia coli 1.5µm
But….
Bacillus megaterium 4 µm
That’s not all!
RBC 8 µm
General Bacterial Shapes
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A. This twisted shape
isn't a rotini, it is the
bacteria Treponema
pallidum, which causes
syphilis. Because of its
shape, this bacteria is
classified as a
spirochete.
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B. The bacteria
Neisseria gonorrhoeae,
which causes
gonorrhea, is
considered a coccus
due to its spherical
shape.
Reproduction
Asexual – production of one or more
genetically identical offspring from a
single parent.
Binary fission “splitting in two”
Resembles mitosis, but simpler:
1. Single DNA strand copies itself
2. Cross wall produced that divides the bacterium
into two identical cells
• In some species, the new cells remain attached to form
pairs, chains, or clusters.
*genetic variations can occur within individual cells
through recombinant events such as mutations
Transduction
The transfer of
viral, bacterial,
or both
bacterial and
viral DNA
from one cell
to another via
bacteriophage.
Conjugation
Two conjugal (mating) pairs
(1 donor, 1 recipient) make
cell-to-cell contact
 Cytoplasmic bridge formed
 Plasmids (sections of genetic
material) are transferred
 Two monerans separate
* Not true sexual reproduction
How do Monerans survive
unfavourable conditions?
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Bacteria can become dormant (rest phase)
Form endospores inside the cell
A thickened wall forms around genetic
material and cytoplasm
Remainder of cell eventually disintegrates
Resistant to heat and not easily destroyed
When conditions are suitable again, the
wall breaks down and activates the
bacterium
Nutrition in True Bacteria
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The success of bacteria is in part due to a wide
variety of ways to obtain energy
While most are heterotrophs, many are
autotrophs
Have developed different methods of respiration
to break down stored food and release energy
– Obligate aerobic
– Obligate Anaerobic
– Facultative anaerobe (alternate between as needed)
Heterotrophs
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Found everywhere
Not able to consume and digest food; must
absorb nourishment from their surroundings
(materials that are already partially digested)
– Saprophytic- feed off dead organisms or organic
waste (decomposers)
– Parasites – live on or in living organisms; cause
harm to the host in some way
Photosynthetic Autotrophs
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“self-feeders” – combine inorganic molecules
from the environment with energy from the
sun to make carbohydrates (glucose –C6H1206)
O2 is given off as waste (blue-green algae were
important in producing this early in life’s
history = creates atmosphere)
In the case of Monerans, they can also absorb
energy directly from the sun due the fact that
they are small and all sides of the cell are
exposed to the environment
Photosynthetic Autotrophs
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Often found in puddles, ponds,
streams, lakes, and moist places.
Important producers in aquatic
communities – basis for all of Earth’s
food chains/webs
(Important role as decomposers –
recycle nutrients through the
biosphere= heterotrophs)
Chemosynthetic Autotrophs
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Some true bacteria are autotrophic but
not photosynthetic (do not use the
sun’s energy to produce food)
Break down inorganic materials like
sulfur and nitrogen
Can be important in converting S and
N compounds so that plants can use it
Nutrition in Ancient Bacteria
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Also known as archaebacteria
Live under conditions that may be very
similar to those found when life was first
evolving on Earth.
All of the known ancient bacteria live
without oxygen and are autotrophs
Some live where no other organisms can
exist today.
Methane-producing Bacteria
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Chemosynthetic (convert CO2 and H2 to
methane)
Inhabit swamps, marshes, and other env’ts
wherever there is a great deal of decaying
plant matter.
Also inhabits the digestive tracts of mammals,
especially grazers
Can be found in sewage treatment plants.
Bonus
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Possible practical use: fuel
Convert decomposing material into a
usable fuel
http://www.preciseenergy.com/biosyst
em.htm
Resource
Review
What would life on Earth be like if there were
no decomposers to break down dead plant
material, the bodies of dead animals, and the
waste products generated by all living
things?
– Eventually, all the nutrients needed for life would
be bound up in this dead matter and waste.
– The raw materials needed to support new life
would no longer be available.