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BACTERIA
What is Bacteria?
BACTERIUM: (singular)
Bacteria are Prokaryotes
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Prokaryotes were the initial inhabitants of Earth and
today are found almost everywhere
Have no _______________________nor
membrane enclosed _______________
Inside the cell is one large circular strand of ____ or
____
PROKARYOTES
Prokaryotes exist in 2 kingdoms:
Bacteria In General:
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Are the _______ most ____________ living
organisms on Earth
All share basic structures but are diverse in cell
____ and ________________ patterns
Affect humans in various ways: cause _______,
spoil foods, can be resistant to ____________
Fix nitrogen for plants, decompose organic matter,
manage hazardous waste, aid animal digestion,
help create dairy products
Bacteria!
General Structure of Bacteria:
Further Investigation...
http://www.cellsalive.com/cells/bactcell.htm
Archaebacteria:
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____________ of all life forms
Hypothesized that all life kingdoms descended from
ancestors of this group!
Organisms in this taxon possess:
Archaebacteria
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Found in extremely _____________ environments
Over half the ______ in archaebacteria differ from
those of eubacteria
Different ___________ classify them into different
kingdoms
Contain specific chemical make-up of cell walls
different from Eubacteria
3 Main Orders of Archaebacteria:
METHANOGENS
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3 Main Orders of Archaebacteria:
HALOPHILES
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3 Main Orders of Archaebacteria:
EXTREME THERMOPHILES
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-develop at temperatures
between 45-80°C, but
some need hotter
temperatures!
-first found living in the hot
springs of Yellowstone
National Park
In Fact....
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Many other organisms are
found in the hot springs of
Yellowstone National Park
and those microorganisms
are responsible for the
vibrant colors of the springs.
Because thermophiles are
ancient, and because they
prefer the steamy conditions
that were typical of the
early times on Earth, many
scientists think they could
help us understand
_____________.
Eubacteria
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Most successful of _________________
Categorized according to their mRNA into
phylogentic groups: GRAM-POSITIVE,
spirochaetes,
chlamydias,
cyanobacteria
proteobacteria
Eubacteria
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Organisms belonging to this taxon possess:
Basic Bacteria Structure:
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Both archaebacteria and eubacteria are classified
according to:
1. Cell Shape
Bacteria cell shapes
come in 3 basic forms:
1.
Round –
2.
Rod –
3.
Spiral -
1. Cell Shape
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Cocci that live as _________
cells = monococci.
Cocci live in ______ =
diplococci
Cocci live in _______ chains
= steptochocci.
Cocci live in ____________
clusters = staphlococci
1. Cell Shape
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Mono =
Di or diplo =
Strepto =
Staphyto =
1. Cell Shape
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Bacilli also exists as single, pairs or chains or
random attachments
Spiral bacteria exist only as single cells
2. Gram Stain
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Gram staining is a differential staining procedure
that allows the categorization of bacteria into 2
groups based on their
2 groups:
OR
2. Gram Stain
GRAM POSITIVE
-Cell walls stain a ________
colour (they retain the stain)
-Gram positive bacteria have
a different cell wall
structure than gram –
negative bacteria and the
stain shows this
- Gram positive bacteria are
quite common and usually
not as pathogenic (cause
disease in a host organism)
2. Gram Stain
GRAM NEGATIVE
-Cell walls stain ______
(unable to retain the
stain)
-usually more ________;
bacteria that cause
typhoid, gonorrhoea,
meningitis and
pneumonia
3. Nutrition
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All cells need energy and a source of carbon for
cellular respiration.
major energy source
light=
Photoautotrophs
Inorganic compounds =
photoheterotrophs
chemoautotrophs
chemoheterotrophs
3. Nutrition
Photoautotrophs:
-can _____________ their
own organic compounds
from sunlight
-Cyanobacteria (a.k.a. Blue
green algae)
-forms blooms in polluted
water due to nitrate and
phosphate run-off into the
water
-use up oxygen in
lakes/ponds/water source
3. Nutrition
Chemoautotrophs:
-obtain energy by ____________________ bonds in
inorganic compounds such as hydrogen sulphide and
ammonia
3. Nutrition
Chemoheterotrophs:
-live everywhere
-some are _____________ and live off _________
-some are ________ and consume decomposing hosts
4. Respiration
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1.
All living things must carry out ______________to
receive energy for life’s functions
Bacteria differ in whether or not they ___________
Bacterial respiration falls into 2 basic categories:
Aerobes
-cellular respiration ______________ to produce
energy from food that is broken down
-_______________________absolutely need
oxygen for survival
4. Respiration
2.
Anaerobes
-bacteria that carry out cellular respiration in an
______________________________
-if the presence of oxygen kills these organisms,
they are called ____________________
4. Respiration
Example: obligate
anaerobe = soil
bacterium called
Clostridium botulinum
that produces toxins
that can cause an
extreme form of food
poisoning called
botulism
3. __________________
can survive in either
environment
Bacterial Reproduction
Depending on environmental conditions, bacteria can
reproduce in a variety of manners:
Under Favourable Conditions:
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All bacteria use _______________(asexual reproduction)
under ideal conditions
Produce ___________ copies of themselves: parent cell
divides into 2 identical offspring
Can divide every ________ minutes
In 12 hours there is 10 to 100 million bacteria!
Genetic _________________ occur which increase their
diversity and ability to survive
Due to fast reproduction rate bacteria mutate often –
____________
If the mutation is favourable then it spreads through the
population quickly
Binary Fission
Under Unfavourable Conditions
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Will reproduce using _____________ if conditions
begin to fail (lack of food, heat, dessication –drying
out- or space)
2 bacteria cells connect to each other by long protein
bridges called a _______ between them
1 cell transfers a copy of their ___ (smaller ring of DNA
with fewer genes than chromosomes) to the other cell
The bacteria that received this plasmid now has a
different genetic make up and this thereby
____________their chances of survival
Example: bacteria become resistant to antibiotics
Conjugation
Under Extreme Conditions:
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Bacteria form structures called spores – one such is
called an _____________________
Many gram positive bacteria form these spores
Endospore:
This enables them to remain _______ for long periods
(months) until conditions are once again favourable
So, endospores do not metabolize or reproduce but
simply ______ until conditions become favourable
Endospores
Endospores
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Example of Clostridium
bacteria with characteristic
drumstick-shaped endosporeproducing cells.
The dark rod-shaped cells are
vegetative cells.
The clear ovals are
endospores, and the objects
consisting of both dark rod
and clear oval are vegetative
cells producing endospores.