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THE PROKARYOTES
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Prokaryotic
Unique genetic structure / Unique RNA
Lipids in membrane allow it to stable at high temperatures
Lack peptidoglycan in their cell wall / some don’t have a cell wall.
Lives in harsh environments (very basic or acidic waters; volcanoes)
Anaerobic
Obtain energy from inorganic molecules or light
Type
Characteristics
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Produce methane
Live in O2-free environments (below the surface of swamps, marshes or
sewage-disposal sites)
Use carbon dioxide, nitrogen gas or hydrogen sulfide as a source of energy
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Live in salty environments / Salt concentrations of up to 15%
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Live in hot acidic environments (hot sulfur springs, volcanoes or near deep sea
vents)
Use sulfur as a source of energy
Grow best at temp. above 80 ºC
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Cold-loving organisms – live in temperatures between -10ºC to -20ºC
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Methanogens
Halophiles
Thermoacidophiles
Psychrophiles
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Prokaryotes
Live everywhere – air, soil, skin, water
Most numerous of all other life forms
Some are helpful – penicillin; bacteria in our large
intestines produces vitamin K, help recycle wastes;
used in production of some foods; nitrogen-fixing
bacteria help recycle N2
Some are harmful – pathogenic bacteria can cause
disease
Factors promoting bacterial growth:
1.
2.
3.
4.
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(1) Shape
Singular
Plural
Shape
Advantages
There are also prefixes associated with characteristic patterns of growth of bacteria.
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diplo - arranged in _________
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staphylo - arranged in _________________________
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strepto - arranged in ________________
(2) Structure of the Cell Wall
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Bacteria differ significantly in their structure and thickness of their _____________________.
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Hans Gram, the Danish physician, investigating tissue samples using ____________________
and ______________________ as stains discovered that _________________ remained in
the _______________________ of some bacteria
Gram Positive Bacteria
Gram Negative Bacteria
There are more Gram negatives than Gram positives and they are also more diverse.
(3) Sources of Food and Energy
Major Energy
Source
Light
(Photosynthetic Bacteria)
Autotrophic
Heterotrophic
Inorganic Compounds
(Chemosynthetic Bacteria)
Autotrophic
(4) Metabolism (pg. 49)
Obligate aerobes
Facultative aerobes
Obligate anaerobes
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1. Asexual reproduction
Some bacteria reproduce asexually undergoing the process
of___________________. The cell grows, makes a copy of its
DNA, elongates and separates the two chromosomes, builds a
partition between them and eventually splits into two cells.
In favorable conditions a bacterium can grow and divide in only
20 minutes! It can double its population size every time it does
asexual reproduction, which allows the bacteria to produce a
large population in a short amount of time (exponential growth).
Heterotrophic
2. Sexual Reproduction
In __________________________ conditions, some bacteria are able to reproduce sexually by a
process known as ___________________. This process produces cells with new genetic
combinations and therefore provides a chance that some may be
_________________________________ to changing conditions.
_______________________ occurs when one bacterium
connects to another bacterium via a ___________. One of
the bacteria then transfers some or its entire DNA through
the ___________ into the other bacterium. That bacterium
then undergoes _______________________________ to
produce more cells with the same make-up.
HWK Questions:
(1) What is a plasmid?
(2) What is transformation?
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Some bacteria, in times that are unfavorable for survival, may lie ________________ in an
________________.
Characteristics of an Endospore
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Tough outer covering that surrounds their DNA and small amount of cytoplasm
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Do not grow or reproduce (dormant)
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Resistant to _________________________________________________________
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Some survive 1000s of years
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When ____________________ conditions return the endospore loses its coat and the bacteria is
__________________________ and ___________________again
• Can be killed in an ____________________ (i.e. pressurized steam).