Characteristics of Bacteria
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Classification
Reproduction
Uses
Controlling Growth
Structure of Bacteria
• Two parts to Bacteria Structure:
–Arrangement
–Shape
3 Shapes of Bacteria
Bacteria are classified by shape into 3 groups:
Spiral:
spirilla, spirillum
Rod-shaped:
bacilli, bacillus
Round:
cocci, coccus
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Shape
• Rod: bacillus
• Round: coccus
• Spiral: spirillum
Bacteria Arrangement
• Paired: diplo
• Grape-like clusters: staphylo
• Chains: strepto
Examples
• Streptococcus: chains of spheres
• Staphylospirillum: Grapelike
clusters of spirals
• Streptobacillus: Chains of rods
Name these bacteria…
Bacterial Reproduction
 Do bacteria reproduce sexually?
Bacterial Reproduction
no
Binary Fission
 Cell division in prokaryotes
 1 cell  2 cells
 genetically
identical (clones)
Bacterial Cell &
Nucleiod DNA Ring
DNA replication
Cell wall synthesis
Cell separation
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Reproduction of Bacteria
BINARY FISSION
Bacteria dividing
Completed
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Conjugation
 Transfer of genes between prokaryotes
(Can occur within AND between species.)
 NOT sexual, but bacteria do
exchange genes.
Have a
plasmid.
pilus
For me!
plasmid
(“ring” of DNA)
Transformation
 “Loose” DNA rings (plasmids) taken
directly from the environment under
adverse conditions or through
biotechnology.
plasmid
(“ring” of DNA)
Reproduction of Bacteria
•The time of reproduction depends on how
desirable the conditions are
•Bacteria can rapidly reproduce themselves in
warm, dark, and moist conditions
•Some can reproduce every 20 minutes
(one bacteria could be an ancestor to
one million bacteria in six hours)
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Endospores
 Endospores = small resistant cells
formed inside existing cells to survive
poor conditions. It’s NOT reproduction.
Bacillus anthracis (anthrax bacterium)
Bacteria Survival
Bacillus subtilis
Endospore-the black section in the middle
highly resistant structures
can withstand radiation, UV light, and
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boiling at 120oC for 15 minutes.
Harmful Bacteria
• some bacteria cause diseases
•Animals can pass diseases to humans
Communicable Disease –
Disease passed from one organism to another
This can happen in several ways:
•Air
•Touching clothing, food, silverware, or toothbrush
•Drinking water that contains bacteria
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Harmful Bacteria
Human tooth with accumulation of bacterial
plaque (smooth areas) and calcified tartar
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(rough areas)
Helpful Bacteria
•Decomposers help recycle nutrients into the
soil for other organisms to grow
•Bacteria grow in the stomach of a cow to
break down grass and hay
•Most are used to make antibiotics
•Some bacteria help make insulin
•Used to make industrial chemicals
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Helpful Bacteria
•Used to treat sewage
Organic waste is consumed by the bacteria,
used as nutrients by the bacteria, and is no
longer present to produce odors, sludge,
pollution, or unsightly mess.
•foods like yogurt, cottage & Swiss cheese,
sour cream, buttermilk are made from bacteria
that grows in milk
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Helpful Bacteria
E.coli on small intestines
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Controlling Bacteria
3 ways to control bacteria:
1) Canning- the process of sealing food in
airtight cans or jars after killing bacteria
•endospores are killed during this process
2) Pasteurization- process of heating milk
to kill harmful bacteria
3) Dehydration- removing water from food
•Bacteria can’t grow when H2O is removed
•example: uncooked noodles & cold cereal
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Controlling Bacteria in People
 Antibiotics = inhibit bacterial growth;
stop reproduction or kill
-directly kill or inhibit the bacteria
(Drugs that inhibit viruses are usually
called anti-virals.)
 Immunization = inject parts of bacteria
or viruses to “train” the immune
system to destroy the pathogen
-make a person’s body uninhabitable for
the bacteria OR viruses
Penicillium Fungus