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BACTERIA
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Bacterial colony
Figure 4.1
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Bacteria are very small
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This is a pore
in human skin
and the
yellow
spheres are
bacteria
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Bacteria are
very small
compared to
cells with
nuclei
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Bacteria
Bacteria
compared
to a white
blood cell
that is
going to
eat it
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Clean skin has about 20 million
bacteria per square inch
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Evolution/Classification
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Most numerous on Earth
Most Ancient
Microscopic Prokaryotes
Adapted to survive where no other organisms
can.
• Grouped based on:
– Structure, physiology, molecular composition,
reaction to specific types of stain.
– Eubacteria= Germs/bacteria
– Archaebacteria
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Kingdom Archaebacteria
• First discovered in extreme environments
• Methanogens: Harvest energy by
converting H2 and CO2 into methane gas
– Anaerobic, live in intestinal tracts
• Extreme halophiles: Salt loving, live in
Great Salt Lake, and Dead sea.
• Thermoacidophiles: Live in acid
environments and high temps.
– Hot Springs, volcanic vents
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Volcanic
vents on the
sea floor
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Chemosynthetic bacteria use the
sulfur in the “smoke” for energy to
make ATP.
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Kingdom Eubacteria
• Can have one of three basic shapes
1. Bacilli – rod-shaped
2. Spirilla – spiral-shaped
3. Cocci – sphere-shaped
Streptococci – in chains
Staphylococci – grape-like
clusters
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Bacillus
bacteria
are rod
shaped
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Coccus
bacteria
are
sphere
shaped
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Spirillium bacteria have a corkscrew shape
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BACTERIA PICS
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Diplo-bacteria
occur in pairs,
such as the
diplococcus
bacteria that
causes
gonorrhea
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Staphylo bacteria occur
in clumps, such
as this
staphylococcus
bacteria that
causes common
infections of cuts
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Streptobacteria occur
in chains of
bacteria, such as
this
streptococcus
bacteria that
causes some
types of sore
throats
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Spirillium bacteria
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Diplobacillus
bacteria
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Streptococcus
bacteria
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Staphylococcus bacteria
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The tip of a
needle
The red and
yellow dots are
bacteria
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Gram Stain
• Gram-positive retain stain and appear purple
– Have thicker layer in cell wall.
– can produce exotoxins made of protein
• Gram-negative do not retain stain and take second pink
stain instead.
– can produce endotoxins made of lipids and
carbohydrates
– Watch it happen! http://youtu.be/aJpZzF3h3kc
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No Nucleus-DNA in Cytoplasm
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Nutrition and Growth
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•
•
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Heterotrophic or Autotrophic
Some are Photoautotrophs – Use sunlight for Energy
Some are Chemoautotrophs.
Many are Obligate Anaerobes.
– Oxygen = Death
• Ex. Clostridium tetani – Tetanus
• Some are Faculatative Anaerobes
– With or without Oxygen
• Ex. Escherichia Coli
• Some are Obligate Aerobes
– Ex.) Mycobacterium tuberculosis
• Temperature requirements
– Some are Thermophilic, Some prefer acidic envmt.29
These
heterotrophic
bacteria digest
oil -remember oil
is partially
decayed plant
and animal
cells
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BACTERIA REPRODUCES
binary FISSION
First the chromosomal DNA
makes a copy
The DNA replicates
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NEXT THE CYTOPLASM AND
CELL DIVIDES
The two resulting cells are
exactly the same
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In addition to
the large
chromosomal
DNA, bacteria
have many
small loops of
DNA called
Plasmids
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CONJUGATION
Exchange DNA through
Conjugation tube/pilus
http://youtu.be/EtxkcSGU698
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Transformation and Tranduction
• Transformation: Bacterial cell takes in
DNA from external environment
– http://youtu.be/eovTbQgan5M
• Transduction: Virus obtains DNA from
Bacterial host
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Examples
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Helicobacter
pylori
is the
pathogenic
bacteria
that can
causes ulcers
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Leprosy is a
bacterial infection
that decreases
blood flow to the
extremities
resulting in the
deterioration of
toes, ears, the nose
and the fingers.
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CHOLERA
DENTAL CARIES
ROCKY MOUNTAIN Spotted Fever
tickborne disease caused by the
bacterium Rickettsia rickettsi
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LYME DISEASE
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SALMONELLA
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STREP THROAT
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TUBERCULOSIS
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BOTULISM
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