Transcript Ch. 19 – Importance of Bacteria!

Ch. 19 – Importance of
Bacteria!
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Used in food –
yogurt, cheese,
sauerkraut
Decompose dead
things
E-coli in your
stomach
Sewage treatment
Nitrogen fixation –
convert nitrogen
from air to a form
that plants can
use.
Bacteria & Disease:
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Examples of disease caused by bacteria:
 Bubonic Plague – carried by fleas on rats.
 “Ring around the Rosie
Pocket full of posies
Ashes, Ashes
We all fall down”
Escherichia coli (E-coli)
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A whole family of bacteria, not all of
which are harmful.
• Good - Depend on E. coli in our
intestines for Vitamin K and B
• Bad - E-coli (0157:H7): symptoms:
Bleeding, loss of water, kidney failure
Some Terms to know:
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Pathogens – viruses and bacteria
that are disease producing agents
Virulence – the ability to cause
disease
3 Steps to Disease
1.
Contamination: pathogens are
present…
a. Through air, food or water
b. Direct contact (touch, body
fluids, etc.)
c. Contact with a carrier of a
pathogen (tetanus [lockjaw] comes
from bacteria found on soil particles)
Tetanus - medical
condition characterized by
a prolonged contraction of
skeletal muscle fibers
3 steps continued…
2.
3.
Infection – pathogens multiply in
body
Disease – disturbance in the
healthy body, so it can no longer
carry out its normal functions.
Bacteria cause disease in one of these 2
ways:
1.
2.
Break down cells
to use as a food
source.
(Mycobacterium
tuberculosis)
Release Toxins
(E. coli)
M. tuberculosis - destroys
lung tissue; can enter
blood stream & destroy
other tissue.
Coping with Disease:
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Immunity – resistance to a pathogen
that is acquired or inherited.
Antibodies – proteins that the body
makes to destroy pathogens.
Antibiotics – drugs that attack and
destroy bacteria. (before these,
people died of things like strep
throat!)
Major Antibiotic:
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Penicillin
• Alexander Fleming
1928 discovered by
accident in lab
• A type of mold
• Different types
(amoxicillin, etc.
come from different
forms of the
Penicillin fungi –
mold)
Controlling Bacteria:
1.
Sterilization – heat of chemicals to kill
bacteria
 Bacteria cannot survive high temperatures
for very long
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Examples: Autoclave at the vet, dentist,
doctors office, etc.
2.
Disinfectants – chemical solutions to
reduce the number of bacteria
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Examples: Antiseptics, Antibacterial
products (soaps, cleansers, kitchen
utensils)
Controlling bacteria
continued…
3.
4.
Soap – wash bacteria away;
may be good enough
Food preservation – salt,
vinegar, sugar, heat, low
temperatures (refrigeration –
doesn’t kill just slows growth!)