ISP 26.1
How Bacteria Are
Classified
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Eubacteria or Archaea (Which Domain?)
Mode of Nutrition
Ability to produce Endospores
Means of Mobility (Flagella?)
Shape (cocci, bacilli, or spirilla)
Gram Stain
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Positive – thick peptidoglycan cell wall
Negative – thin peptidoglycan cell wall
Prokaryotic Nutrition
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Bacteria differ in their need for, and tolerance of,
oxygen (O2).
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Obligate anaerobes are unable to grow in the
presence of O2; ex. botulism, gas gangrene, and
tetanus
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Facultative anaerobes are able to grow in either the
presence or absence of gaseous O2.
Aerobic organisms (Obligate aerobes) - including
animals and most prokaryotes) require a constant
supply of O2 to carry out cellular respiration.
How Bacteria Obtain Energy

Every type of nutrition, except for ingestion of
whole food, is found in bacteria.
 Autotrophs – manufacture their own organic
compounds
 Photoautotrophs
 Chemoautotrophs
 Heterotrophs – must obtain their energy by
consuming organic substances produced by
autotrophs.
 Parasites
 Saprophytes (Saprobes)
 Decomposers
Pasteur’s experiments
disproved the long held
belief in
spontaneous generation
Reproduction in Prokaryotes
Sources of Genetic Variation

In bacteria, genetic recombination can occur in
three ways.
1. Conjugation - occurs when a bacterium passes
DNA to a second bacterium through a tube (sex
pilus) that temporarily joins two cells; occurs only
between bacteria in same or closely related species.
2. Transformation - involves bacteria taking up free
pieces of DNA secreted by live bacteria or released
by dead bacteria.
3. Transduction -bacteriophage transfer portions of
bacterial DNA from one cell to another.
Bacterial Conjugation
Bacterial Conjugation Link
Transformation in Bacteria
Transformation in Bacteria Link
General Transduction
General Transduction Link
Endospore Formation

Some bacteria form resistant endospores in
response to unfavorable environmental conditions.
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Endospores survive
in the harshest of
environments: desert
heat and dehydration,
boiling temperatures,
polar ice, and
extreme ultraviolet
radiation.
Heterotrophic
Prokaryotes
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Some heterotrophs are symbiotic,
forming intimate, long-term
relationships with members of
other species; includes:
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Mutualistic
Commensalistic
parasitic relationships
The bacteria of
genus Rhizobium
invade the roots
of legumes –
resulting in the
formation of
nodule – The
bacteria convert
atmospheric
nitrogen to an
organic nitrogen
that the plant
can use
Heterotrophic Prokaryotes
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Commensalistic bacteria live in or
on organisms of other species and
cause them no harm.

Parasitic bacteria are responsible for
a wide variety of infectious plant,
animal and human diseases.
The Bacteria Gram Stain & Shape

The Gram stain procedure (developed by Hans
Christian Gram) differentiates bacteria.
 Gram-positive bacteria stain purple,
whereas Gram-negative bacteria stain
pink.
 This difference is dependent on the thick or
thin (respectively) peptidoglycan cell wall.
The Bacteria
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Bacteria and archaea have three basic
shapes.
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spirillum - spiral-shaped.
bacillus - elongated or rod-shaped bacteria
Coccus - bacteria are spherical
Cocci and bacilli tend to form clusters and
chains of a length typical of the particular
species.
The Archaea

Carl Woese - base sequence of their
rRNA differs from Bacteria
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Other differences:
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Archaea do not have peptidoglycan in
their cell walls like the Bacteria
Archaea biochemical more like Eukarya
than Bacteria
Archaea now thought to be more
closely related to Eukarya than to
Bacteria
The Archaea
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Types of Archaea
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Methanogens live under anaerobic
environments (e.g., marshes) where
they produce methane.
Halophiles require high salt
concentrations (e.g., Great Salt Lake).
Thermoacidophiles live under hot,
acidic environments (e.g., geysers).
Kingdom Protista
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Catch all Kingdom - artificial & used more
for convience.
Eukaryotic cells (Endosymbiotic Theory)
Most are unicellular (some filamentous,
colonial or multicellular)
Animal-like, plant-like or fungus-like
Asexual reproduction the norm, but some
reproduce sexually.
Endosymbiotic theory
Kingdom Protista
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Complexity
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Eukaryotic
Autotrophic or Heterotrophic
Highly varied life cycles (asexual & sexual
reproduction)
Highly specified organelles
Symbiotic relationships
(parasitismmutualism)
The Green Algae

Green algae are believed to be closely
related to the first plants because both
of these groups
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have a cell wall that contains cellulose,
possess chlorophylls a & b
store reserve food as starch inside of the
chloroplast.
Red Algae
Brown Algae
Diatoms & Golden Brown Algae
CO 22
Dinoflagellates
Red Tide
Euglenoids
Zooflagellates
Ameboids
Ciliates
Sporozoans
(Malaria)
Slime Molds
Slime Molds
Water Molds
Figure 22.19
Kingdom Fungi
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Multicellular Eukaryotes
Heterotrophic by absorption
Saprotrophic decomposers -breaking down
wastes or remains of plants & animals
Parasitic, mutualistic
Others form an association with a green alga
or cyanobacterium to form a lichen
Energy reserve Glycogen (unlike plants)
Terms to know:
Hyphae
(singular hypha)
Mycelium
(singular mycelia)
Chitin
Figure 23.3
Pg 410
Yeasts are
unicellular
& reproduce
asexually by
mitosis or
budding
Yeast
is important
in the Yeasts fermentation
produce ATP through
fermentation
production
wine,
beer
& breads
ethanol
& COof2 are
waste
products
Athletes Foot
Ringworm
Club Fungi – Mushrooms
Fairy Ring
Club Fungus – Shelf Fungus
Figure 23.9b
Figure 23.9d
Symbiotic Relationships of Fungi
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Lichens are a symbiotic association
between fungus and cyanobacterium or
green alga
Three types of lichens are recognized.
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Compact crustose lichens are often seen on
bare rocks or tree bark.
Leaflike foliose lichens
Shrublike fruticose lichens
Symbiotic Relationships of Fungi
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Mycorrhizae are mutualistic
relationships between soil fungi and
roots of most plants
It helps the roots absorb more
minerals; in turn, the plant passes on
carbohydrates to the fungus