pptx

Prokaryotes

Chapter 27

Slide
2

of 20

Kingdom
Monera



Prokaryotes


Unicellular (Single
-
celled)
organisms that lack
membrane
-
bound
organelles and nuclei


Divided by

1. Domain

2. Nutritional Classification

3. Reactivity with Oxygen


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Domain Classification

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Nutritional Classification

AUTOTROPHS

1.
Photoautotrophs


Photosynthetic autotrophs
–

Like plants


Light energy


Energy (ATP)


Carbon dioxide


organic compounds (Glucose)


2.
Chemoautotrophs


Inorganic substances


Energy (ATP)


Carbon dioxide


organic compounds (Glucose

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Nutritional Class (Page 2)

HETEROTROPHS

3.
Photoheterotrophs


Light energy


Energy (ATP)


Get carbon from consuming other organisms


3.
Chemoheterotrophs


Get both carbon & energy from consuming other
organisms

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of 20

Reactivity with Oxygen


Whether they must react with O
2
, must be in absence
of O
2
, or they can be in absence or not of O
2


Obligate aerobe
–

Require O
2

for respiration


Obligate anaerobe
–

O
2

is a poison to them


Facultative anaerobe
–

Prefer to use O
2
, but don’t need
to use it to live


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Questions


Which of the 3 classifications is appropriate for
humans?


What would you call something that uses light for
energy, but must obtain carbon in an organic form?


Aerobes would do what form of catabolism?


What about anaerobes?


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of 20

Roles of Prokaryotes


Decomposers

–

recycle dead organic manner


Pathogens

–

organisms that cause disease


Nitrogen Fixation


Atmospheric N
2



NH
4


ONLY way to fix nitrogen into organic systems


Play a vital role in
genetic engineering


E. Coli is used to manufacture human insulin

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of 20

Bacteria’s Roles (Page 2)


Symbionts

in the gut
–

Manufacture vitamins


Digest cellulose


Digest Food


Bioremediation

–

remove pollutants


Used in production of
cheese & yogurt

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Symbiotic Roles


Symbiotic
–

relationships with other species


Mutualism

–

Both
symbionts

benefit


Pollinators & Flowering plants



Commensalism

–

One organism benefits other is
unharmed


Fern growing in the shade of a tree



Parasitism

–

One benefits at the expense of another


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Antibiotics


Chemicals that kill prokaryotes


Usually produced by fungi


NOT effective against viruses


Many plasmids confer resistance to different antibiotics


MDR
-
TB

–

Multi
-
Drug Resistant (resistant to multiple
antibiotics) Tuberculosis bacteria


XDR
-
TB

–

eXtremely
-
Drug Resistant (resistant to almost
every antibiotic) Tuberculosis bacteria


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Archaebacteria


Unicellular


Prokaryotes


No Peptidoglycan
in their cell walls


Able to live in extreme environments


Resemble the first cells on Earth


Extreme
Halophiles

–

Salt lovers


Extreme
Thermophiles

–

exist in extreme temperatures (high
temperatures)


Methanogens

–

Use CO2 to oxidize H2


Produce methane as a by product


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Examples of Archaebacteria

Thermoacidophiles

Hot Springs
-

Thermophiles

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Eubacteria


Broadly categorized as Gram
-
negative or Gram
-
positive


Due to whether the bacterium is able to take up Gram’s
stain


Gram
-
positive
–

large amount of peptidoglycan in cell
wall


Susceptible to antibiotics


Gram
-
negative
–

structurally more complex cell wall


Contains less peptidoglycan


Outer membrane contains
lipopolysaccharides


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5 Important Bacterial Subgroups


Proteobacteria


Chlamydias


Spirochetes


Gram
-
Positive Bacteria


Cyanobacteria

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of 20

Proteobacteria


Includes photoautotrophs,
chemoautotrophs
,
and
heterotrohps


Some are aerobic, others are anaerobic


Nitrosomonas

–

Nitrogen fixing bacteria


Examples:


Escherichia coli (E coli)
–

benign & pathogenic


Vibrio

Cholerae

–

Cholera


Rhizobium

–

live in roots of legumes

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of 20

Chlamydias
,
Spirochets


Gram
-
negative like
proteobacteria


Chlamydias


ALL are parasitic


Lack peptidoglycan


Chlamydia = most common STD or VD


Spirochetes


Helical shape


Move by rotating internal flagella
-
like
filaments


Syphilis and Lyme disease


Others are free
-
living (not parasitic or
pathogenic)

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of 20

Gram
-
positive Bacteria


Diversity rivals
proteobacteria


Streptomyces

–

source of many
antibiotics


Bacillus
anthracis


Clostridium
botulinum


Mycoplasms

–

bacteria that lack
cell walls (WTF?)


Synthetic organism?

Slide
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of 20

Cyanobacteria


ONLY photoautotrophs


Plant
-
like photosynthesis


May have
heterocytes

–

can fix
nitrogen