Download Chapter 18 Viruses & Bacteria

VIRUSES
Chapter 18
Bacteria
Viruses
&
Bacteria
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Viruses
• NOT considered living therefore viruses
are NOT placed into any kingdom
• Viruses are not cellular
• Viruses do not carry out respiration
• Viruses are non motile
• Viruses do not grow
• Viruses can not make proteins
• Viruses no metabolism or homeostasis
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Viruses
• Viruses are NON LIVING particles (sub cellular)
that can reproduce only when in a living cell.
• Found basically everywhere ( Air, Water, Soil)
• Viruses are smaller than prokaryotes.
• Viruses can only be viewed w/electron
microscope.
• Viruses are pathogens
• BACTERIOPHAGE is a special type of virus that
infects only bacteria (bacteria eaters)
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Viruses
• Viruses even though they are non living
are called parasites b/c they feed on
lining things
• HOST CELL is a cell in which a virus
reproduces
• REVERSE TRANSCRIPTASE is an
enzyme that when injected into a host cell,
it will copy viral RNA into DNA
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Virus
LYTIC CYCLE
1. Virus attaches to a host cell.
2. Virus injects its nucleic acid into the host
cell.
3. The host DNA is destroyed and the virual
genes are copied.
4. New virus particles are assembled.
5. The host cell breaks open and the new
virus particles are released.
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BACTERIA
• PROKARYOTE
– NO internal membrane organelles
– NO NUCLEUS
• CIRCULAR DNA
– Plasmid
• All bacteria are unicellular
– Some may colonize but are not multicellular as
the activities of the cells of the colony are not
specialized
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Bacteria
• KINGDOM
• Old five (5) kingdom hierarchy
– Monera
• New six (6) kingdom hierarchy
– Eubacteria
– Archaebacteria
• Scientists think – 1st bacteria
(anaerobic)
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BACTERIA
• When you are sick there is something in your body that
makes you feel nauseous, what is it? It’s bacteria.
Bacteria are a germ that you can’t see with the naked
eye. You might not be able to see them but there are
billions of them all over you. Sometimes bacteria are bad
but sometimes it helps us fight infections. One form of
bacteria causes bad breath. If your gums and teeth are
healthy then the problem is your tongue. You might
already know, but bacteria come in all different shapes
and sizes. Typically there are three certain shapes of
bacteria round, rod-shaped, and spiral bacteria. They are
also classified into groups very specifically.
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BACTERIA
• Classified many different ways. One way
is by shape
• Three basic shapes
– BACILLUS (rod)
– SPIRRILUM (spiral)
– COCCUS (sphere)
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Bacillus
(rod)
Coccus
(Sphere)
Spirrilum
(Spiral)
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Typical bacterial Cell
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Archaebacteria
“Extremists”
• Ancient ones
• Live in extreme environments
• Ribosomal RNA is different from Eubacteria
rRNA
• Three types
– Grouped by where they live
• Marshes/sewage/digestive tracts some mammals
• Water w/high salt conc. Great Salt Lakes/Dead Sea
• Deep cracks in the ocean floor
• Autotrophic and/or Heterotrophic
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Archaebacteria
Unicellular
Prokaryotes
Form and Metabolism are different than in any other organisms
Found in areas sheltered from evolutionary alteration
unchanging habitats
Resemble earth’s early environment
living relics
• surviving representatives of first ages of life on earth
Produce methane and cluster together as a group
No peptidoglycan (murien) cell wall
Get food by sunlight, organic compounds, and inorganic
compounds
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Eubacteria
• True bacteria
• Heterotrophic – live almost everywhere
– Some are parasitic
– Some are saprophytes
– Some use organic molecules as their food
• Photosynthetic Autotrophs – live in places w/sunlight
– Cyanobacteria – introduced oxygen into the earth’s atmosphere
• Chemosynthetic – break down and release the energy of
inorganic cpds. w/sulfur & nitrogen
• Convert atmospheric nitrogen into nitrogen-containing
cpds that plants need.
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BACTERIA
• Unique cell walls
• Cell wall needs to stay intact.
• Penicillin kills bacteria by causing holes to
develop in the cell wall
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BACTERIA
How does a bacterium’s
cell wall protect it?
The cell wall prevents water from entering
by osmosis and causing it to burst
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Bacteria
A. Where is the genetic material of a
bacterium found?
B. What structure do some bacteria use to
move?
• A. As a plasmid or circular chromosome
within the cell’s cytoplasm
• B. Flagella
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Bacteria
more beneficial ones than pathogenic ones
• Some Uses
– Farming
– Medical industry
– Food industry (Swiss cheese/yogurt/sour
cream /vinegar/sauerkraut/ pickles
– Nitrogen fixation
– Recycle nutrients
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Good Bacteria
• Some of the good bacteria are in our
stomachs, helping digest food. While
others are important in the production of
dairy products such as cheese, yogurt,
buttermilk, and sour cream. Just
remember that you can eat foods that
have bacteria just as long as it's good
bacteria
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Good Bacteria
• A researcher in Canada is trying to
encourage the use of bacteria pesticides to grow
on crops. Scientists at a university located in
Winnipeg did some tests to see how this
bacteria would effect the plants. After adding an
exceptional amount of water they added bacteria
that causes food poisoning. These bacteria
include E. Coli and Salmonella. This prevented
insects from eating the plants. This will also
reduce the amout of chemical pesticides that
could harm are ecosystem.
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Nitrogen fixing bacteria
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Bacteria - uses
• Nitrogen fixation – Most of the Earth’s nitrogen
exists in atmospheric gas form. 80% of the
Earth’s atmosphere
• All organisms need nitrogen but very few can
use it directly from the atmosphere.
• Several species of bacteria have enzymes that
convert atmospheric nitrogen into ammonia
• Some bacteria convert the ammonia into nitrites
and nitrates
• Plants then use the nitrites/nitrates
• ONLY bacteria can carry out these processes
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Bacteria
Some evolutionary adaptations in bacteria
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Reproduce Rapidly by BINARY FISSION
High rate of mutation
Exist in Adverse conditions
Can utilize substances harmful to other organisms
Simpilcity of the cell structure
Some are aerobic
Some are anaerobic
Some are facultative aerobes (both w/wo oxygen)
Some are obligate anaerobes – w/o oxygen – release
energy by fermentation
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Bacteria
• Some can carry out Nitrogen Fixation – a
process by which bacteria convert nitrogen
gas (atmospheric nitrogen) into ammonia.
• Reproduction
– Commonly – Binary Fission (asexual)
– Conjugation (sexual) may occur as well – is a
simple form of reproduction. Conjugation
brings about an exchange of genetic material
between bacterial cells – allows for diversity
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Why can’t bacteria reproduce by
mitosis or meiosis?
• B/c they do NOT have a nucleus, and
instead of pairs of chromosomes they
have one circular chromosome and
varying numbers of smaller circular pieces
of DNA called plasmids.
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Bacteria
• Bacterial reproduction can occur rapidly – every
20 minutes by binary fission.
Why does this not occur?
• They would cover the surface of the Earth within
a few weeks. They would run out of nutrients
and water, they would poison themselves with
their own wastes
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Bacteria
• ENDOSPORE – structure in some bacteria that
is resistant to adverse environmental factors
(protects the bacteria)
• ENDSPORE – bacterial form that is in a state of
slow metabolism and that does not reproduce.
• ENDOSPORES – may be harmful to other
organisms. – C.botulinum endospores will
produce toxins and result in causing botulism in
other organisms (deadly food poisoning)
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Most Common Bacteria
• Escherichia Coli
• E coli is a very common Actually it is the most
common species of bacteria. Theodore
Escherich discovered the bacteria, E. Coli. This
bacteria does not have one particular
environment that it lives in. It could be found in
places such as hot springs and radioactive
wastes. E. Coli also live in the intestine and help
to break down food
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Bad Bacteria
• Bacterial Meningitis is an infection that affects
the lining of the brain and the spine. There have
been reports about this disease causing death
lately, but this illness can be treated if it is found
early. It can be caused by bacteria, widespread
virus, and chemicals. Bacteria forms of
Meningitis are more serious. This bacteria can
get into your bloodstream. If you don’t treat it
then it could cause paralysis, severe brain
damage, and damage to other organs.
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• Salmonella is another type of bacteria.
It is commonly found in poultry, eggs,
meat,
and water. If you have a pet turtle or bird
they may carry it. It attacks the stomach
and intestines. To keep from getting
Salmonella you should wash your hands
after touching anything that might carry
Salmonella.
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Bacteria
• TOXIN – poison produced by some
bacteria
– Food poisoning (both salmonella/botulism)
Some bacteria are pathogenic
• Streptococcus pneumoniae – causes pneumonia
• Name tells you that the bacteria are arranged as long chains
of round cells (coccus-sphere shaped or round)
• Gonorrhea. Syphilis/Tuberculosis/ Diphtheria/Tetanus
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Bacterial Food Poisoning
• Fungi, viruses, and bacteria can cause
food poisoning; however, bacteria related
food-borne illnesses are the most
common. Bacteria usually develops on
raw foods. Remember it is a decomposer
and it breaks down material as it feeds on
it. If you don’t cook your food thoroughly
then you allow bacteria to grow and
spread on your food
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