BIOL 260-General Microbiology
Instructor: Jennifer Ward
What is microbiology?
• The scientific discipline
which studies microbes or
microorganisms
– The biology of microbes
– The interaction of microbes
with other microbes, the
environment, and humans
Question to think about (advance notice = this will be a
2 point extra credit question on the final exam): why is
microbiology important?
**Types of microbes**
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Algae
Fungi
Protozoa
Bacteria
Archaea
Viruses
Know the basic
characteristics of each
type of microbe, as
outlined in slides 8-13.
Note that since we have
covered bacteria and
viruses in more depth
you will be expected to
know more about these
types of organisms than
what is covered in these
slides.
Kingdoms give way to Domains
1. Kingdom was
formerly the highest
level of classification
2. Initially all organisms
were separated into 2
Kingdoms: Plantae
and Animalia
3. Discovery of
microscope >
realization of greater
complexity in our
world > new levels of
classification added
Kingdoms give way to Domains
• The 5 Kingdom
system:
– Monera, Protista,
Fungi, Plantae,
Animalia
• The 6 Kingdom
system:
– Split Monera to form
Archaebacteria and
Eubacteria
• The 3 Domain system
– Archaea
• Kingdom Archaebacteria
– Bacteria
• Kingdom Eubacteria
– Eukarya (or Eucarya)
• Kingdoms Protista,
Fungi, Plantae &
Animalia
• Next revision = ?
Three Domain System
Know the 3 domains; know
which of the eukaryotes fall
under the study of microbiology;
know the basic differences
between eukaryotic and
prokaryotic cells
Types of Microbes:
Algae
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Domain: Eukarya (“true nucleus”)
Kingdom Protista
Unicellular and multicellular species
Photosynthetic
Rigid cell walls (do NOT contain peptidoglycan)
Many are motile
These organisms have an
interesting life cycle but I
will NOT ask you about it
on the exam so don’t
worry about memorizing
this diagram!
Types of Microbes:
Fungi
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Domain: Eukarya (“true nucleus”)
Kingdom: Fungi
Unicellular and multicellular species
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Molds, yeasts & higher fungi
Chemoheterotrophs; many are saprophytic
Rigid cell walls (do NOT contain peptidoglycan)
Sexual and asexual life stages
Again, cool life
cycle, but it
won’t be on
your exam
Types of Microbes:
Protozoa
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Domain: Eukarya
Kingdom: Protista (for now)
Unicellular species
Chemoheterotrophs
No cell wall
Sexual and asexual life stages
Most are motile (cilia, flagella, pseudopodia)
Int. hosts
Toxoplasma gondii
trophozoites
Things I might ask you about T. gondii:
1. What is the definitive host?
2. Name one intermediate host.
3. What are 2 ways that other species (accidental hosts,
including people) become infected?
Definitive
host
Life cycle of Toxoplasma gondii
Types of Microbes:
Viruses, viroiods &
prions
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Non-living infectious agents
All living organisms have
viruses
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Viruses: DNA or RNA + protein coat
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Viroids: DNA or RNA
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Uses host cell mechanisms for replication of DNA or
RNA and protein transcription
Use host cell mechanisms for replication
Prions: protein
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Abnormally folded protein
Induces conformational change in native proteins to the
abnormal form
Diseases currently known/believed to be caused by prions:
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Bovine spongiform encephalopathy (aka mad cow disease)
Kruezfield-Jacobs disease
Kuru
Scrapie
Chronic wasting disease
Types of Microbes:
Archaea
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Domain: Archaea
Kingdom: Archaebacteria
Prokaryotic cells (“Prenucleus”)
Unicellular species
No membrane-bound organelles
Genetic material localized to nucleoid
Cell wall (no peptidoglycan)
Most divide by binary fission
Some are motile (flagella)
Adapted to extreme environments
Types of Microbes:
Bacteria
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Domain: Bacteria
Kingdom: Eubacteria
Prokaryotic cells (“Prenucleus”)
All are unicellular species
No membrane-bound organelles
Genetic material localized to nucleoid
Rigid cell wall – contains peptidoglycan
Most divide by binary fission
Some are motile (flagella)
In nearly all environments
Only a small percentage of the species we know
are pathogenic
The Binomial System of Nomenclature
• Living organisms:
classified (and reclassified) according to
Binomial System
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Know what the binomial
system is, which part of
the name refers to genus
and which refers to
species, which is the
broader category and
which is more specific,
and what the convention is
for writing the proper
names of organisms.
Note that the convention is that we
either italicize or underline the formal
latin names when we identify an
organism to species – when writing free
hand these should be underlined, since
we can’t italicize in free hand.
Escherichia coli [“Escherichia” =
genus, “coli” = species]
Staphylococcus aureus
Helicobacter pylori
Toxoplasma gondii
Histoplasma capsulatum
Mycoplasma hemofelis
(Hemobartonella felis)
Classifications are based on our current best understanding of
phylogeny and this understanding evolves with new knowledge