Types of
Microbes
JAHS Microbiology 2015
Types of Microorganisms
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Bacteria
Prokaryotes: genetic material is NOT enclosed
inside a nucleus
Archaea
Fungi
Eukaryotes:
Protozoa
has a nucleus
containing the
Algae
cell’s DNA
Multicellular Animal Parasites
Viruses
Classification of Microorganisms
The Three Domains of Life
● Bacteria
● Archaea
● Eukarya
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Protists
Fungi
Plants
Animals
The Three Domains of Life
Carl R. Woese Pioneered the use of
ribosomal RNA as a
molecular chronometer
to construct
phylogenetic trees.
Bacteria
● Prokaryotes
● Peptidoglycan cell
walls
● Binary fission
● For energy, use
organic chemicals,
inorganic chemicals,
or photosynthesis
Bacteria
There are three
common bacterial
shapes:
● Bacillus: rod-like
● Coccus: spherical
● Spiral: corkscrew
shaped or curved
Archaea
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Prokaryotic
Lack peptidoglycan
Live in extreme environments (NOT all!)
Include
○ Methanogens
○ Extreme halophiles
○ Extreme thermophiles
● Not known to cause disease in humans
Fungi
● Eukaryotes
● Chitin cell walls
● Use organic chemicals
for energy
● Non-photosynthetic
● Some cause disease in
humans
Fungi
● Some are unicellular
○ Yeasts
● Some are multicellular
○ Molds and mushrooms
■ Consist of masses of
mycelia - composed
of filaments called
hyphae.
Protozoa
● Unicellular eukaryotes
● Absorb or ingest organic
chemicals
● May be motile via
pseudopods, cilia, or
flagella
● Reproduce sexually or
asexually
Algae
● Eukaryotes
● Cellulose cell walls
● Use photosynthesis for
energy
○ Produce molecular oxygen
and organic compounds
● Reproduce sexually or
asexually
Viruses
● Acellular
● Consist of DNA or RNA core,
surrounded by a protein coat
○ Coat may be enclosed in a lipid
envelope
● Viruses are only replicated
when they are in a living host
cell
Multicellular Animal Parasites
● Eukaryotes
● Multicellular animals
● Parasitic flatworms
and roundworms
are called helminths
● Microscopic stages
in life cycles.