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Bacteria Chapter 24
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Classification Structure Physiology Molecular composition Reactions too stain rRNA sequences
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Archaebacteria aka: ancient bacteria Unusual lipids in cell membrane- no petoglycan Introns in DNA Cell walls lack peptidoglycan Genes closely related to early eukaryotes Extreme environments
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Archaebacteria
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Methanogens –Convert H 2 and CO 2 into methane gas –Live in anaerobic environment –Found in intestinal tracts of humans and other animals Extreme halophiles –Salt lovers –Use salt to generate ATP –Found in Dead Sea
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Archaebacteria Thermoacidophiles –Live in acidic environments pH <2 –Live in high temperatures up to 230 –Live near volcanic vents and cracks in the ocean floor
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Gram staining pg 471 Gram-positive - appear purple under a microscope –Thicker peptoglycan –Causes different resistance to antibiotics –Produce different toxins Gram-negative - do not retain stain appearing pink under a microscope
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Gram Staining
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Eubacteria aka: new bacteria Three basic shapes –cocci –bacilli –Spirilla Strepto= Chains Staphlo= Grape like clusters 12 different phyla according to evolutionary relationships
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Cocci
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Bacilli
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Spirilla
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Eubacteria Cyanobacteria –Autotrophic Makes its own food Photosynthetic –“Blue-green algae” –Often cling in colonies –Thrive on nitrates and phosphates in a body of water Population bloom or eutrophication
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Cynobacteria aka: blue green algae
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Eubacteria Spirochetes –Gram-negative –Spiral shaped –Heterotrophic Cannot make its own food Example- Treponema pallidium (Syphilis)
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Spirochetes
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Eubacteria Gram-Positive Bacteria –Not all are gram-positive –Cause tooth decay –Turn milk into yogurt –Causes strep throat
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Eubacteria Proteobacteria- largest most diverse group –Enteric bacteria inhabit animal intestines (E. Coli) –Chemoautotrophic Gram-negative bacteria Oxidizes chemicals –Nitrogen-fixing bacteria Convert nitrogen into ammonia
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E. Coli
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Nitrogen-fixing Bacteria pg 467-475
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Structure Cell Wall –Eubacteria - peptidoglycan Cell Membrane –Acts like mitochondria in cells –Contains enzymes that speed up cellular respiration Cytoplasm –Contains DNA, ribosomes, & organic compounds
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Structure Capsules –Outer covering that protects the cell and assist in attaching the cell to other surfaces Pili- used for adhesion –Hairlike protein structures that transfer genetic material from one bacterium to another Endospores –Dormant structure protecting against harsh conditions –When conditions are right, bacteria emerge.
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Yogurt
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Nutrition and Growth Saprophytes - feed on dead and decaying material Photoautotrophic – uses the sun to make its own food (blue-green algae) Obligate anaerobe - cannot live in presence of oxygen (Tetnus) Facultative anaerobe - Can live with or without oxygen (E.coli)
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Nutrition and Growth Obligate aerobes - Cannot live without oxygen (Turberculosis) Thermophilic - Grow between 104 - 230
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Bacteria and Disease Pathology - Studying diseases Toxins = poisons Exotoxins = Toxins made of proteins (Gram-Positive Bacteria) Endotoxins = Toxins made of lipids and carbohydrates (Gram-Negative Bacteria) –Not released till bacteria die –Cause fever, aches, weakness
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Antibiotics Combat bacteria by interfering with various cellular functions Resistance –Mutated bacteria that is resistant to antibiotics can continue to grow and reproduce Example- Penicillin attacks bacteria cell walls
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Body’s Defense
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Useful Bacteria Insecticides Clean up environmental disasters Produce and process food Turn sewage into simpler organic compounds
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Bacteria Replication
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Binary fission Divides a prokaryotic cell into 2 off spring cells
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Binary fission cont. DNA is copied
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Binary fission cont. Cell begins to divide
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Binary fission cont. Two identical haploid cells (original # of chromosomes)
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Binary Fission
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More terms to know Population bloom Capsule Saprophytes Pathogen Conjugation –2 bacteria connect and transfer genetic material to each other.
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