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Published byNelson Tate Modified over 9 years ago
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Ch. 19
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Eubacteria ◦ Largest kingdom of living things ◦ Live everywhere ◦ Cell wall contains peptidoglycan Archaebacteria ◦ Cell wall lacks peptidoglycan ◦ DNA sequences more similar to eukaryotes ◦ Live in extreme environments
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Shapes ◦ Rod (bacilli) ◦ Spiral (spirilla) ◦ Spherical (cocci)
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Cell walls ◦ Gram-positive stained have peptidoglycan call walls (violet) ◦ Gram-negative lack peptidoglycan (red) Movement ◦ Variety of ways….
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Heterotrophs ◦ Chemoheterotrophs and photoheterotrophs majority Autotrophs ◦ Photoautotrophs Cyanobacteria ◦ Chemoautotrophs
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Obligate aerobes ◦ Require oxygen all the time; aerobic respiration Mycobacterium tuberculosis Obligate anaerobes ◦ Killed by oxygen; anaerobic respiration Clostridium botulinum Facultative anaerobes ◦ Can survive with or without oxygen; both types of respiration Eschericia coli
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Binary fission ◦ Mitotic; asexual Conjugation ◦ Gene swapping; sexual Sporulation ◦ When conditions become unfavorable DNA and a little cytoplasm is enclosed in an endospore
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Decomposers Nitrogen fixers Food industry Mining Cleaning oil spills Pharmaceuticals Oxy Clean
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Bits of DNA or RNA surrounded by a protein coat. That’s it. ◦ They come in a variety of shapes and sizes ◦ They must infect a host cell to reproduce. ◦ Bacteriophages are viruses that infect bacteria.
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Viruses enter a host cell and use the cell’s machinery to reproduce. ◦ In lytic infections the virus reproduces immediately until the cell bursts. ◦ In lysogenic infections the viral DNA is incorporated into the host’s DNA as prophage and may remain dormant for a period of time until reproduction begins.
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Contain RNA instead of DNA ◦ After infecting a cell the RNA is copied in reverse to make DNA which is then incorporated into the host cell’s genome as prophage. ◦ RNA viruses mutate frequently. Rhino virus (colds) HIV
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Are viruses alive?
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Bacteria and viruses can act a pathogens – disease causing agents (pathos = disease; gen = generating). ◦ Louis Pasteur helped formulate the germ theory of disease. ◦ Bacteria cause disease by either using cells for food or by releasing toxins (poisons) that are harmful.
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Sterilization with heat Disinfectants Cold storage Vacuum packing Nitrogen/inert gases
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Some target the cell wall of bacteria and others disrupt protein synthesis. ◦ Antibiotics are specific to the type of bacteria they act upon.
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Can’t be treated with antibiotics! They don’t have a cell wall or make proteins… ◦ Best treatment is prevention; once infected it has to run its course. Symptoms may be treated.
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Vaccines provide some protection and immunity to bacterial and viral diseases. ◦ More to follow…
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