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Transcript
Ch 18.1 Bacteria
 one celled prokaryotes (“before nucleus”)
 first life on earth and most numerous
 divided into two kingdoms
1. Eubacteria
 live almost everywhere (soil, air, water, and
inside others)
 have cell wall of peptidoglycan
 some have second cell wall
2. Archaebacteria
 have different membrane lipids and
ribosome proteins
 more like eukaryotes than eubacteria
 may be ancestors of eukaryotes
 live in harsh environments
 thermoacidophiles
 halophiles
 methanogens
Identifying Prokaryotes
 by shape - bacilli, cocci,
spirilla (spirochete)
 By arrangement - diplo, strepto and
staphylo
 by cell wall type- gram positive or gram
negative,
 by way they move –flagella, spiraling, gliding
or no movement
- by way they obtain energy
 Autotrophs capture energy to make food
-photoautotrophs called cyanobacteria
- chemoautotrophs (break down hydrogen
sulfide)
 Heterotrophs must eat to get energy and
nutrients
- saprobes decompose organic molecules
(dead stuff)
-by the way they break down
molecules in respiration
 some need oxygen for respiration –
obligate aerobes
 some can only live in absence of oxygen –
obligate anaerobes
 some can live in both – facultative
anaerobes
Benefits of bacteria
1. Most important role is ecological
-breakdown and decomposition of
organic matter (decay)
- makes nutrients available for others
- cleans the environment
Other Benefits of Bacteria
2. Nitrogen fixation - converts nitrogen in air, to a
useable form for plants (in soil or in nodules on
legumes)
3. Food production – cheese, butter, yogurt and pickled
products
4. Drug and chemical production thru genetic engineering (growth hormones, insulin, antibiotics)
5. Can digest small oil spills, remove poisons from water
4. Help digest food and production of vitamin K in
digestive tract
Pathogens
– disease causing agents
 Examples : pneumonia, diptheria, typhoid,
leprosy, strep and staph infection
 harm organisms by:
1 direct attack (tuberculosis)
2. releasing harmful toxins (poisons)
ie. salmonella and botulism, strep,
diptheria
Protection against Bacteria:
1. barriers (skin, mucous membranes)
2. white blood cell attack
3. vaccine-weakened or killed bacteria that
stimulate the body to produce antibodies
4. antibiotics -penicillin - discovered by Alex
Fleming in 1929
Growth and Reproduction
 Asexual reproduction – binary fission – produces
identical daughter cells
 Conjugation – genes are passed from one cell to another
thru pili
- new combinations of genes results in greater
diversity
 Endospores form in unfavorable conditions – protects
DNA for
years
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Double Bonus: Bacteria Eat Pollution, Generate Electricity
Scientists have long studied bacteria that can clean up toxic waste by eating it.
Other bacteria have been employed to produce electricity.
Now scientists have found a two-for-one deal in bacteria that will eat toxic
chemicals 24/7 and make electricity to boot.
"The bacteria are capable of continuously generating electricity at levels that
could be used to operate small electronic devices," says Charles Milliken of the
Medical University of South Carolina, who conducted the research with
colleague Harold May. "As long as the bacteria are fed fuel they are able to
produce electricity 24 hours a day."
The new study involved Desulfitobacteria, already known for their ability to
breakdown and detoxify some of the most problematic environmental
pollutants, including PCBs and some chemical solvents.
"These bacteria are very diverse in their metabolic capabilities, including the
food that they can consume. That means that these bacteria can convert a
large number of different food sources into electricity," says Milliken. "The
technology could be used to assist in the reclamation of wastewaters, thereby
resulting in the removal of waste and generation of electricity."
The bacteria perform their useful tasks while in spore form, a dormant stage of
growth that can handle extreme heat, radiation and lack of water -- all useful
traits for an organism that might be employed in some of the worst manmade
environments.
Related News
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 Waste Not: Energy from Garbage and Sewage
 Jolted Bacteria Make Hydrogen from Human
Waste
 Bacteria Uses Sonar-Like Strategy to Probe
Environment
 Personal Nuclear Power: New Battery Lasts 12
Years
 Scientists Make Bacteria Behave Like Computers
 » Is Antibacterial Soap Really Necessary?
 » Bacteria Found Nearly 2 Miles Underground
 » New Approach Disarms Deadly Bacteria
 » Space Yogurt Made With Astro-Bacteria
 » Microbots Designed to Swim Like Bacteria
 » Intestinal Bacteria May Explain Obesity
 Eureka! Bacteria Have the Midas Touch
 » Bacteria & Fungi Ride Dust Across Oceans
 » Starving Bacteria Cooperate to Make
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'Superstrain'
» Picture Perfect Method to Detect Deadly
Bacteria
» Bacteria vs. Bacteria: The New Fight Against
Salmonella
» Bacteria in Yogurt Modified to Fight HIV
Infection
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» Bacteria Used as Photo Film