Introduction to Bacteria
2 TYPES OF BACTERIA:
•Bacteria
-Get food from an outside source
•Blue-green Bacteria
-Make their own food
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BACTERIA
Bacteria - small one celled monerans
Bacteria like a warm, dark, and moist
environment
They are found almost everywhere:
-water
-air
-soil
-food
-skin
-inside the body
-on most objects
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3 Shapes of Bacteria
Bacteria are classified by shape into 3 groups:
Spiral:
spirilla
rod-shaped:
bacilli,
bacillus
Round:
cocci
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3 Shapes of Bacteria
Bacillus anthracis –
(bacillus)
Neisseria meningitidis
(coccus)
Leptospira interrogans –
(spirilla)
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7 Major Structures of a Bacteria Cell
•Capsule
•Cell wall
•Ribosomes
•Nucleoid
•Flagella
•Pilli
•Cytoplasm
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7 Major Structures of a Bacteria Cell
Capsule
 keeps the cell
from drying out
and helps it
stick to food or
other cells
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7 Major Structures of a Bacteria Cell
Cell wall
Thick outer
covering that
maintains the
overall shape of
the bacterial
cell
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7 Major Structures of a Bacteria Cell
Ribosomes
 cell part where
proteins are made
 Ribosomes give
the cytoplasm of
bacteria a granular
appearance in
electron
micrographs
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7 Major Structures of a Bacteria Cell
Nucleoid
 a ring made
up of DNA
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7 Major Structures of a Bacteria Cell
Flagella
 a whip-like
tail that some
bacteria have
for locomotion
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7 Major Structures of a Bacteria Cell
Amimation of E.coli
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7 Major Structures of a Bacteria Cell
Pilli
 hollow hair-like
structures made
of protein
allows bacteria
to attach to
other cells.
Pilli-singular
Pillus-plural
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7 Major Structures of a Bacteria Cell
Cytoplasm
 clear jelly-like
material that
makes up most
of the cell
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Reproduction of Bacteria
•Binary Fission- the process of one organism
dividing into two organisms
•Fission is a type of asexual reproduction
•Asexual reproduction- reproduction of a
living thing from only one parent
How?...
The one main (circular)
chromosome makes a
copy of itself
Then it divides into two
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Reproduction of Bacteria
BINARY FISSION
Bacteria dividing
Completed
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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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Bacterial Cell &
Nucleiod DNA Ring
DNA replication
Cell wall synthesis
Cell separation
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Bacteria Survival
Endospore•a thick celled structure that forms inside
the cell
•they are the major cause of food poisoning
•allows the bacteria to survive for many years
•they can withstand
boiling, freezing, and
extremely dry conditions
•it encloses all the
nuclear materials
and some cytoplasm
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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.
Bacteria Survival – Food sources
parasites – bacteria that feed on living things
saprophytes – use dead materials for food
(exclusively)
decomposers – get food from breaking down
dead matter into simple chemicals
important- because they send minerals
and other materials back into the soil so
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other organisms can use them
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
E.coli on small intestines
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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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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
Antiseptic vs. Disinfectants
Antiseptic- chemicals that kill
bacteria on living things
•means – “against infection”
Examples: iodine, hydrogen peroxide,
alcohol, soap, mouthwash
Disinfectants- stronger chemicals that
destroy bacteria on objects or nonliving
things
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BLUE-GREEN BACTERIA
Autotrophs – make their own food
through photosynthesis
larger than most bacterial cells
commonly grow on water and surfaces that
stay wet…such as rivers, creeks and dams
Some live in salt water, snow, and acid
water of hot springs
food source for animals that live in the
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water
BLUE-GREEN BACTERIA
can be toxic to humans and animals
Blooms- occur when the
bacteria multiplies in great
numbers and form scum on
the top of the water
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Lake Champlain
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Bacillus anthracis rod, vegetative stage
prokaryote
(bacterium)
Image Number:
21185A
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Neisseria meningitidis
- coccus prokaryote
(bacterium)
Image Number:
97214E
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Leptospira
interrogans
- spiral
shaped
prokaryote
(spirochete)
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Strep animation
http://www.hybridmedicalanimati
on.com/pages/jjani_qt/strep_pne
umo_qt.html
Ecoli movement animatoin
http://www.hybridmedicalanimati
on.com/pages/jjani_qt/ecoli_qt.h
tml
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Ecoli movement animatoin
http://www.hybridmedicalanimation.com/pa
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ges/jjani_qt/ecoli_qt.html
HIV movie
http://www-micro.msb.le.ac.uk/Video/HIV.mov
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