Transcript Bacteria
Bacteria By Diana L. Duckworth Rustburg High School Campbell County Differences with Eukaryotes http://bhs.smuhsd.org/bhsnew/a cademicprog/science/vaughn/St udent%20Projects/Paul%20&% 20Marcus/Cell_Replication.html • Prokaryotes – no internal cell organization • Eykaryotes are 10 x larger than prokaryotes • No true multicellular bacteria – cells not specialized • Single strand of DNA (circular); eukarya linear • Reproduction by binary fission – cell just pinches in two; lengthy process in Eukarya • Flagella are more simple; also have pilli • Can be either aerobic or anerobic; more diversity in types of metabolism 3 shapes of bacteria • Bacillus (rod) • Coccus (round) • Spirillum (spiral) http://sciences.unlv.edu/desertsurvivors/Pages/episode2.htm Two types of Cell Wall • Distinguished by staining – Gram Positive – Gram Negative • Determines susceptibility to antibiotics Staphylococcus aureus Pink – Gram negative Blue – Gram positive http://library.med.utah.edu/kw/derm/pages/in06_5.htm How bacteria obtain energy http://user.uni-frankfurt.de/~schauder/cyanos/cyanos.html • Autotrophs – Photosynthesis – use light to fix carbon • Some are obligate anerobes, others aerobes • Cyanobacteria – source of oxygen in atmosphere. – Chemosynthesis – energy from ammonia, hydrogen sulfide, methane – Important in nitrification (ammonia to nitrate) • Heterotrophs – important decomposers of dead organisms – Rhizobium – nitrogen fixing bacteria in roots of legumes (nitrogen to nitrate) – Gangrene http://abdellab.sunderland.ac.uk/lectures/Parmacology/ANSdoc/serotonin8.html Bacterial Pathogens – humans are food Anthrax – air borne http://srs.dl.ac.uk/Annual_Reports/AnRep01_02/anthrax.htm Vector - fleas http://webs.wichita.edu/mschneegurt/biol103/lecture14/lectur e14.html http://health.usnews.com/articles/health/2008/01/03 /12-diseases-that-altered-history/photos/ Bubonic Plague www.acponline.org/graphics/bioterro/u_ec.jpg http://www.jyi.org/features/ft.php?id=102 Lyme Disease http://gracelings.blogspot.com/2007_07_01_archive.html Bacterial Toxins (food & water) Tuberculoses http://sudanwatch.blogspot.com/2006/03/adrawater-capacity-improvement-in.html Botulism Cholera http://anthropik.com/2006/12/industria l-agriculture-the-e-coli-outbreak/ E. coli http://www.wnysmart.org/botulism.htm http://letsgoeverywhere.wordpress.com/2007/11/ 19/i-survived-cholera-epidemic-2007/ Fighting Bacterial Infections • Prevention – hygene; especially in food preparation • Antibiotics – During WWII – huge advancement – Alexander Fleming – Penicillium (fungus) secretes penicillin – Different antibiotics effective against different cellular processes • Problem – antibiotic resistance; mutations spontaneous & spread – Favored by misuse of antibiotics – stopping treatment when feel good, not going entire course – Prescribing antibiotics when not effective (e.g. viruses) – Benign bacteria can develop mutation & share it with pathogenic bacteria Useful Bacteria • Natural in foods – yogurt, cheese, pickles, sourdough bread, buttermilk, etc. • Genetically engineered to produce important compounds • Engineered to clean up environmental contamination – oil spills • Engineered to concentrate low grade ores