Bacteria
• Bacteria are pro karyotes
“first seed” (single cells
that do not contain a
nucleus, or membrane
bound organelles).
• Bacteria are microscopic
and can only be seen
through a microscope
• There are 2 Domains of
bacteria, Eubacteria and
Archaea
Eubacteria “true bacteria”
• Typical “monerans” found
where humans live
• Evolution of the 3 Domains
Archaea “archaic/old”
extremophiles
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Methanogens
Thermophiles
Acidophiles
Halophiles
Alkaliphiles
Psychrophiles
Xerophiles
Barophiles
• Archae vs Bacteria
Bacteria Characteristics
• Bacteria are
distinguished from
other living things
because of their
cell structure:
• All bacterial cells
have a cell wall
surrounding a cell
membrane, inside
of which lies the
unbound nuclear
matter and other
material.
• Bacteria have
extra genomic
DNA that is
round and called
a “plasmid”
• Plasmid
Cloning
Bacteria Classification
• There are three types of bacterial cells, based on
shape: spherical (coccus), rodlike (bacillus), and
spiral (spirillum).
Coccus
Bacillus
Spirilla
• Some bacteria have flagella for locomotion and
some have pili to transfer DNA (conjugation)
and to stick to substrates of host cells
Bacterial Chemotaxis
Gram Staining
• The Gram stain is named
after the 19th century Danish
bacteriologist who developed
it.
• The bacterial cells are first
stained with crystal violet.
then treated with alcohol or
acetone, whichwashes the
stain out of gram-negative
cells and then counterstained.
• Bacteria that are not
decolorized by the
alcohol/acetone wash are
gram-positive.
• Gram Stain Animation
Gram +
• Stains purple
• Cell wall 90%
peptidoglycan
Gram • Stains red
• Multi-layered cell wall
with inner and outer
membranes and an
intermembrane space
Harmful Bacteria
• A number of bacteria
cause disease, these
are called pathogenic
bacteria.
• They can cause
diseases of plants,
animals, fungi,
protists and other
bacteria
• E. coli infection
• Salmonella infection
• Some bacterial
diseases include: strep
throat, scarlet fever,
toxic shock syndrome,
pneumonia, ear
infections, gonorrhea,
syphilis, Tuberculosis
• Bacteria can also be
used by some
countries to harm
other countries in an
act called bioterrorism
Eczema w/ 2o infection
Helpful Bacteria
• actinomycetes,
produce antibiotics
such as streptomycin
and nocardicin
• live symbiotically in
the guts of animals
• Bacteria put the tang
in yogurt and the
sour in sourdough
bread
• roots of certain
plants, converting
nitrogen into a
usable form.
• break down dead organic matter
• of such immense importance because of their
extreme flexibility, capacity for rapid growth and
reproduction, and great age - the oldest fossils
known, nearly 3.5 billion years old
• used in genetic engineering
Bioremediation
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Bacteria are useful in making
antibiotics and in biotechnology.
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Symbiotic bacteria assist in digestion
Producers in Geothermal Vents
Reproduction
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Bacteria reproduce asexually by binary fission
Bacterial Conjugation (lateral/horizontal gene exchange)
Bacterial Transformation (lateral/horizontal gene exchange)
Bacteria life cycle
Response to the Environment
• Intracellular signaling not only brings bacteria
together in biofilms (through Quorum sensing
A process by which a bacterium detects the
density of other bacteria in an area), it also
regulates the coordinated delivery of high
doses of these antibiotics from the denser
bacterial population.
• Biofilm Life Cycle
Bacterial Links
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Bioterrorism:
Bacterial Cell Walls:
10 Ways a World Will End: Monster Plague
Discovery of the Germ Theory
Antibiotics Tutorial
Anti-antibiotics/Efflux Pump
Immunology Primer
When Worlds Collide, Macro vs. Micro
Immuno- biology Animations