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Chap. 23 : Bacteria I. Characteristics of Bacteria 1. Unicellular – live in colonies 2. Prokaryotes 3. A sample is called a culture 4. Grown in lab on media called agar (algae) 5. Domain Archae or Bacteria A. Archeabacteria Peptidoglycan - sugar/protein found in cell walls but only in Eubacteria. 3 Groups : --- Methanogens – convert H and CO2 into methane gas. Forms marsh gas.Found in cows intestines --- Halophiles – salt-loving --- Thermoacidophiles – acid and hot places. Volcanos and ocean vents. B. Eubacteria :Gram Staining Gram Positive – stain purple, have more peptidoglycan so first stain (which is purple) sticks. Usually more harmful. (botulism, strep, staph, syphilis, anthrax) Gram Negative – stains red, have less peptidoglycan so first stain washes out and the 2nd stain (which is red) remains. C. Eubacteria :Classified by their shape 1. Coccus ( cocci ) – round shape a. diplococus – pairs of cocci b. staphylococcus – (boils) – clusters of cocci. c. streptococcus – (strept throat) – chains of cocci 2. Bacillus (bacilli)- rod-shaped ex. E. coli – found in our intestines and used for digestion. ex. Botulism – type of deadly food poisoning (can goods and oysters) 3. Spirillium (spirilla) – spiral-shaped ~~ ex. Syphyllis – STD II. Bacterial Structure III. Respiration 1. Obligate aerobes – requires oxygen to live. Ex. Diptheria ( trachae) and TB (lungs) 2. Obligate anaerobes – cannot live in presence of oxygen. Ex. Tetanus, Syphillis, Halotosis, and Botulism 3. Facultative Bacteria –can live with or without oxygen. Ex. E.coli IV. Adaptations for survival Endospores – hard outer covering around some bacteria used to survive harsh conditions. Some can survive up to a thousand years. Ex. Botulism and tetanus V.Reproduction 1. Binary fission – one cell pinching into two. Asexual ( occurs about every 20 min.) Reason you should take antibiotic until completely gone. 2. Conjugation – sexual – two bacteria exchange their genetic information through their pili VI.Benefits of Bacteria 1. Make products like Swiss cheese, pickle, yogurt, butter, sauerkraut, coffee, cocoa 2. Breakdown our food 3. Breakdown waste and return nutrients back to soil 4. Fix nitrogen (change N to a form we can use) 5. Used as medicines (antibiotics) VII.Controlling Bacteria Need warm, wet, dark environment to grow 1. Canning – heat food, seal containers while hot, no air 2. Pasteurization – heating milk to kill bacteria 3. Refrigeration and freezing – slows bacterial growth 4 Dehydration – getting rid of water in foods – kills bacteria – ex. pasta 5. Antiseptics – chemicals that kill bacteria on living things. Ex. Iodine, alcohol 6. Disinfectant – chemicals that kill bacteria on non-living things. Stronger than antiseptic. Ex. bleach, ammonia, chlorine 7. Antibiotics (kill bacteria once in body) and Vaccines ( prevent bacteria from occurring) VIII. Blue-green Bacteria: Cyanobacteria Once considered a plant because they can photosynthesize. Has cell structure like bacteria Help produce oxygen and fix nitrogen