oxidized into nitrate or nitrite and used to fertilize crops to feed the growing population. Bacteria: o The first life forms that originated 3.8 billion years ago o Archaea dominated the planet until about 1.5 billion years ago when eukaryotes were created. o In the human body there are probably about twice as many bacterial cells as human cells. o Bacteria are called prokaryotes and lack nucleus, cytoskeleton or sex. o There are very few bacterial species. o Importance of Bacteria: Photosynthesis Nitrogen – fixation
Biogeochemical cycles Decomposition Production of soils Basis of food webs in the ocean and on land Food such as cheese, beer, wine, soy sauce, pickles, etc. o Less than 0.5% of bacteria cause diseases, however they are very deadly such as Tuberculosis. o Cyanobacterial products: Oxygen Ozone Nitrogen/Ammonium Gold Copper Iron Limestone Plants and algae (chloroplast) o Prokaryotes VS Eukaryotes: Prokaryotes Eukaryotes Lack nuclei Have cell walls DNA floats around freely Not bounded No sex Very small Reproduce at a very fast rate Have nuclei Animal cells don’t have cell walls, but plant cells do Mitochondria DNA is bound together by a plasma Membrane-bound organelles MUCH larger than prokaryotes
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- Spring '08