Download Reproduction of Bacteria

Ahh! Germs – Everywhere!
Germ = microorganisms (microbes)
*tiny life forms that multiply
Examples: Viruses, Fungi, Bacteria
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What are bacteria/Why should I
care?
• You may have over a billion bacteria
on the inside and outside of your
body right now
• Maybe half a million under each
fingernail
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BACTERIA
Bacteria – unicellular, prokaryotes
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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7 Major Structures of a Bacteria Cell
•Capsule
•Cell wall
•Ribosomes
•Chromosome
(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
More likely to
cause disease
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7 Major Structures of a Bacteria Cell
Flagellum
 a whip-like
tail that some
bacteria have
for locomotion
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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 and
exchange genetic
material
Pilli-plural
Pillus-singular
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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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7 Major Structures of a Bacteria Cell
Ribosomes
 cell part where
proteins are made
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7 Major Structures of a Bacteria Cell
Chromosome
 a ring made
up of DNA,
contains most
of bacterium’s
genes
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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
Prevents bursting
in hypotonic
environment
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Plasmid
• A few genes located in
a small circular
chromosome (may
have one or more
plasmids)
• The key to
resistance…bacteria
pass on plasmids to
other bacteria, and they
typically code for
resistance to antibiotics
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3 Shapes of Bacteria
Bacteria come in different shapes and sizes
Spiral:
spirillum
rod-shaped:
bacillus
Round:
coccus
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Bacteria Arrangements
• Diplo = pairs of
cells
• Staphylo =
grape-like
arrangment
• Strepto = chain
of cells
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THE SIX
KINGDOMS
Archaebacteria
Eubacteria
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Archaebacteria
Bacteria found in extreme environments
3 Types:
1. methane-producing (swamps, digestive
tracts of cows & other mammals)
2. Salt-loving
3. Heat and acid loving (cracks in ocean
floor, hot springs)
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Anaerobic
• Can live without oxygen – often oxygen
would kill them
• Ex. Bacteria in swamps
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Eubacteria
• Found: Almost everywhere
• 3 Types:
1. Heterotrophs
Parasites (feed on living organisms)
Saprophytes (feed of dead organisms and waste)
2. Photosynthetic
3. Chemosynthetic
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Chemosynthesis:
• Making energy by
breaking down sulfur
and nitrogen
compounds
(ex. Bacteria convert N2
in the atmosphere into
usable form for plants
– nitrogen fixation)
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Bacteria = prokaryote
3 differences between bacteria and animal cell
1. Bacteria= no nucleus, Animal = nucleus
2. Bacteria = Flagellum, Animal = no
flagellum
3. Bacteria = cell wall, Animal = no cell wall
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How can we get rid of bad bacteria?
• Antibiotics = chemical
that kills bacteria
• The first antibiotic:
1929
– Penicillin (made from
mold)
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How does an antibiotic work?
• Makes holes in cell wall causing the cells to
rupture
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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 the cell divides into two
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Reproduction of Bacteria
BINARY FISSION
Bacteria dividing
Completed
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Sexual Reproduction = conjugation
• Bacteria connect by pilli and transfer part of
their chromosome
Like an
airport
skyport
transferring
people!
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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
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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 walled 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.
Tetanus
• Clostridium tetani
• Produce a powerful nerve toxin
• Endospores can exist almost anywhere, if
get into a wound they germinate and
produce toxin
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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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Botulism
• Clostridium botulinum
• On foods, if foods aren’t canned properly
they form an endospore and then germinate
in the anaerobic environment of the can
• Produce toxins – can cause food poisoning
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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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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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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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The Wanted List
•
•
•
•
Create flyers for a gallery of “Most Wanted”
(beneficial bacteria) and “Least Wanted”
(pathogenic bacteria). For each flyer:
provide a mug shot (picture) of the bacterium
name the bacterium (you can add humor, e.g., Sly
the Salmonella typhi)
indicate where it might be found (its natural
hangout)
specify it’s crime (e.g., poison suspect) or benefit
(e.g., yogurt helper)
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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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