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I. Bacteria A. B. C. D. E. F. G. Introduction Various functions/roles of bacteria Diseases caused by bacteria Classification of bacteria Metabolism Structure of bacteria Reproduction A. Introduction 1. 2. 3. Thought to cause human and animal disease actinomycetes, produce antibiotics such as streptomycin and nocardicin; Some live symbiotically in the guts of animals (including humansecoli Leptospira-disease in livestock Intro. Cont. 4. 5. 6. 7. 8. 9. Bacteria put the tang in yogurt Put the sour in sourdough bread break down dead organic matter bacteria make up the base of the food web in many ecosystems extreme flexibility, capacity for rapid growth and reproduction, and great age-they have been around a very long time! nearly 3.5 billion years old-are fossils of bacterialike organisms. B. Functions/Roles of Bacteria 1. 2. 3. 4. 5. 6. Nitrogen fixation a. convert nitrogen into a usable form on the roots of plants Recycling of nutrients a. break down dead organic matter Foods a. Used in food to put the tang in yogurt and the sour in sourdough bread Medicines a. produce antibiotics Cause disease Genetic Engineering!!!! C. Diseases Caused by Bacteria D. Classification of Bacteria 1. Kingdom a. 2. Monera Phylums: a. Archaebacteria b. Eubacteria 3. Archaebacteria a) b) c) Known as the extremophiles Live in extreme environments that would kill other microbes Also know as the ancient bacteria 4. Extreme Thermophiles d) Extreme Thermophiles e) f) g) Hot pots Hydrothermal vents 2 1 High temperatures Sulfur Thermus Aquaticus –taq polyermase used in PCR Hot spring (yellow patches are mats of microbial growth) d. Examples of Extremophiles i. Thermophiles 1) 2) 3) 4) high temperature (80 degrees to 105 degrees C) for growth Sulfur-oxidizers grow at low pH (less than pH 2) because they acidify their own environment by oxidizing S (sulfur) to H2SO4 (sulfuric acid). inhabitants of hot, sulfur-rich environments associated with volcanism, such as hot springs, geysers etc. Yellowstone National Park, and thermal vents ("smokers") and cracks in the ocean floor examples e. Extreme Methanogens Methanogens live a) marshes lake sediments digestive tracts b) mammals (cows) sewage disposal plants. Natural Gas e. Extreme Methanogens c) d) e) methanogens produce methane (CH4) metabolism created most the natural gas (fossil fuel) reserves that are tapped as energy sources for domestic or industrial use can be exploited to produce energy from waste materials f. Extreme Halophiles locations 1) Dead Sea Great Salt Lake Evaporating Ponds 2) Salt loving 3) Halobacterium halobium Purple membrane bacteriorhodopsin heterotrophs f. Extreme Halophiles 1) Halobacterium halobium, prevalent in the Great Salt Lake, adapts to the high-salt environment by the development of "purple membrane", 2) 3) 4) pigment in the plasma membrane rhodopsin called bacteriorhodopsin reacts with light in a way that forms a proton gradient on the membrane allowing the synthesis of ATP. Absorb green light and reflect red and blue Evolutionary link to photosynthesis Eubacteria-true bacteria E. Metabolism 1. 2. 3. Obligate aerobes a. Require oxygen b. Mycobacterium tubberculosis tuberculosis Obligate anaerobes a. Killed by oxygen b. Treponema pallidium Syphilis c. Clostridium botulinum Botulism Both with or without oxygen (facultative) a. cellular respiration b. fermentation Syphilis Botulism E. Metabolism 4. Heterotrophs a) b) Use organic molecules as food source Parasites Obtain nutrients from living organisms a) Saprophytes Feed on dead organism organic wastes Recyclers or decomposers-contain cellulase enzymes E. Metabolism Photosynthetic Autotrophs 5. a. Use Sunlight to make food b. c. d. Live in Ponds, streams, moist areas of land Cyanobacteria Blue-green, red or yellow Chains of independent cells Eubacteria Chemosynthetic Autotrophs Make food from chemosynthesis Sulfur Nitrogen Convert unusable atmospheric nitrogen into nitrogen containing compounds plant can use. nitrogen fixation by bacteria such as Rhizobium Convert sulfur to sulfuric acid Sulfur-oxidizers grow at low pH (less than pH 2) because they acidify their own environment by oxidizing S (sulfur) to H2SO4 (sulfuric acid). Why Yellowstone stinks! F. Bacterial Structure 1. 2. Very small cell Lack membrane bound organelles 3. Lack nuclear membrane 4. 5. Ribosomes DNA circular Nucleoid Biochemical processes in cytoplasm Plasmids –loops of DNA Typical Bacteria Cell Electron Micrograph of E. Coli Plamids G. Reproduction 1. 2. Asexual sexual 1. Asexual BINARY FISSION Asexual Reproduction a. b. c. d. Copies chromosome Attach to cell’s plasma membrane DOUBLING THEIR NUMBERS EVERY 20 MINUTES **favored for genetic engineering** 1928 1 Fleming discovers penicillin the first antibiotic. Inhibits cell wall growth! 2 3