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
Slide
3
of 20
Domain Classification
Slide
4
of 20
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
Slide
5
of 20
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
Slide
6
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
Slide
7
of 20
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?
Slide
8
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
Slide
9
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
Slide
10
of 20
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
Slide
11
of 20
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
Slide
12
of 20
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
Slide
13
of 20
Examples of Archaebacteria
Thermoacidophiles
Hot Springs
-
Thermophiles
Slide
14
of 20
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
Slide
15
of 20
Slide
16
of 20
5 Important Bacterial Subgroups
Proteobacteria
Chlamydias
Spirochetes
Gram
-
Positive Bacteria
Cyanobacteria
Slide
17
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
Slide
18
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)
Slide
19
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
20
of 20
Cyanobacteria
ONLY photoautotrophs
Plant
-
like photosynthesis
May have
heterocytes
–
can fix
nitrogen
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