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VIRUSES(What the heck are they?)
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The Common Cold Virus
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Oh Goodness, My E. coli has a Virus!
Viruses and Bacteria
It's easy to mix these up since compared to us, both are
VERY SMALL.
Great link for size comparison!
Source: http://www.cellsalive.com/phage.htm
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The basics Viruses are:
non-living much smaller than the smallest cell pieces of genetic coding (DNA or RNA) “gift-wrapped” in a protein coat
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Diversity of Capsids
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Diseases caused by viruses include:• Common cold• Flu• Polio• Rabies• Herpes (chickenpox,cold sores, genital)• Warts• Measles, Mumps• Ebola• AIDS
Viruses cannot be killed with antibiotics because they are not alive!
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Antibodies attacking AIDS Virus
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Diversity of Life
Introduction to Prokaryotes
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Figure 13.27a
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Figure 13.27b
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Prokaryote Diversity
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• Two types of Prokaryotic organisms: Eubacteria (bacteria) and Archaea
Visual Summary 15.3
Prokaryotes
Domain Bacteria Domain Archaea(e.g., extremophiles)
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Archaea – Thermophiles in a Nevada geyser.
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Archaea in a hot spring.
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Archaea – Halophilesin seawater evaporatingponds near San Francisco Bay.
Salinity increases from3% to 20% during the production of salt.
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Archaea(a.k.a. “Archaeabacteria)
Prokaryotic (like eubacteria) Biochemically resemble eukaryotic cells Believed to be the ancestors of eukaryotic cells Today: only live in harsh environments
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(Bacteria Review)
What do you already know about bacteria??
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Bacteria on the tip of a pin.
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• Major Episodes in the History of Life
Visual Summary 15.1
Millions of years ago
475570
1,0001,7002,5003,5004,500
Major Episode
Plants and fungi colonize landAll major animal phyla establishedFirst multicellular organismsOldest eukaryotic fossilsAccumulation of atmospheric 02
Oldest prokaryotic fossilsOrigin of Earth
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ALL CELLS have
• Plasma membrane
• DNA
• ribosomes
Generalized structure of bacteria cell
22Figure4.5x2
23Bacterial shapes: cocci, rods, spirals
24Cyanobacteria or “blue-green algae”
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Bacterial colonies growing in culture.
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Detriments to Humans
• Bad breath, tooth decay
• Food poisoning
• Some are pathogenicpathogenic –
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Some Diseases caused by bacteria
• Strep throat
• Cholera
• Tubercolusis
• “the plague”
• Anthrax
• Toxic shock syndrome
• Syphilis, Gonorrhea,
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How cure bacterial infections?
(Antibiotics)(Antibiotics)
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Discussion Question:Should we drop “bacteria bomb?”
• Are there benefits to bacteria that outweigh
their detriments to humans????
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Benefits of Bacteria• Decomposers! chemical cycling• Cyanobacteria were original producers of oxygen
atmosphere ozone• Origins of mitochondria & chloroplasts
• Aid humans in digestion (E. coli)• Allow cows to digest cellulose (grass)
milk, ice cream, hamburgers!• Lactic acid fermentation
(yogurt, buttermilk, sauerkraut)
• bioremediation• Nitrogen “fixers” (to be explained in Unit IV!)