Bacteria
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Transcript of Bacteria
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Bacteria
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Kingdom Archaebacteria
ProkaryotesSingle celledCell Wall (does not have peptidoglycan)Live in harsh environments3 major groups
1) methanogens – swamps, digestive tracts2) halophiles – salty areas3) thermoacidophiles – hot & acidic areas
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Kingdom Eubacteria
ProkaryotesSingle celledCell wall with peptidoglycanCan live almost anywhere
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3 major bacterial shapes
1) Cocci – round2) Bacilli – rod3) Spirilli – spiral
Other terms about bacterial arrangements1) Strep = chains2) Staphylo = clusters
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Bacteria are classified according to
1) Cell wall composition (gram staining)2) Evolutionary relationship (phylogeny)3) Shape4) Motility (how they move)5) Genetics/DNA6) Metabolism (autotroph or heterotroph)
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Gram Staining
Uses 2 colored stains to determine the amount of peptidoglycan in the bacterial cell walls
Gram + = purple, peptidoglycan, penicillinGram - = red/pink, low peptidoglycan
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Helpful bacteria
• Most (about 90%) of all bacteria are harmless or helpful to us.
Can be used for:1) foods (cheese, buttermilk, yogurt, etc…)2) decomposers 3) used in industry
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Harmful bacteria
• Some bacteria can be pathogens (disease causing)
Bacterial infections & diseasesstrep throat food poisoning (botulism)gonorrhea tuberculosissalmonella lyme diseasetetanus
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What makes some bacteria harmful?1) toxins
(Exotoxins- are released by living bacteriaEndotoxins- are released when the bacteria
die)
2) the bacteria destroy tissues
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How do we treat bacterial infections?
ANTIBIOTICS – drugs that inhibit or kill bacteria
There are several types of antibiotics. Some are made from fungi or other bacteria.
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Problems caused by antibiotics
1) Antibiotic resistance2) Some people have reactions to
antibiotics
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Special structures
Capsules – some bacteria form a hard outer covering to protect them from drying out or your bodies immune system
Pili – short, ahir-like structures on the bacterial surface, used to help bacteria “stick”.
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3) Endospores – another covering that protects the bacteria from a harsh environment, allows the bacteria to go dormant.
4) Flagella – whip-like tail to help with movement
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Bacteria & reproduction
Reproduce asexually by binary fission
Reproduce sexually by conjugation (exchange genetic information between 2 bacteria)
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How bacteria get their energy
1) Heterotrophssaprophytes – decomposers
2) Autotrophsphotoautotrophs – photosynthesis
(no chloroplasts!!)
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Some bacteria need oxygen – obligate aerobes
Some bacteria die around oxygen – obligate anaerobes
Some bacteria can live with or without oxygen – facultative anaerobes
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