1. Bacteria and Archaea Allen, Viosa, and Ali

2.  Prokaryotes  Three Domains  Characteristics  Phylogeny  Environmental

3.  Bacteria—prokaryotes  Archaea—prokaryotes  Eukarya—eukaryotes Genetic studies clearly indicate that all three domains had a single common ancestor.

4. Three Common Bacteria Shapes: Sphere Sphere —coccus (plural cocci) Rod Rod—bacillus (plural bacilli) Spiral or helical Spiral or helical —helix (plural helices) Shapes of Archaea: Little is known Many have never been seen. Known only from DNA samples from the environment. Shapes and Prokaryotes Singly Plates Blocks Clusters

5. Locomotion is by flagella. Reproduce asexually by binary fission Most successful organisms on Earth in terms of number of individuals Thick cell walls Communicate with chemical signals In chains or clusters Individual cells = fully viable and independent. Filaments Filaments – chains of prokaryotes Peptidoglycan Peptidoglycan- a polymer of amino sugars contained within the cell wall Not in Archaea Quorum sensing Quorum sensing

6. communities contain different species, including microscopic eukaryotes. sometimes referred to as microbes. perform beneficial services, (e.g., digestion of our food, breakdown of municipal wastes). Many form biofilms.

7. gel-like polysaccharide matrix that traps other cells. Form on contact with a solid surface. Difficult to kill cells in a biofilm Difficult to kill cells in a biofilm Biofilms form in many places: Contact lenses, artificial joint replacements, dental plaque, water pipes, etc. Communicate with chemical signals Communicate with chemical signals Ways to block the signals are being investigated

8. reveals the complexity of bacterial cell walls. The method uses two different stains—one violet and one red. Bacteria either: Gram-positive Gram-negative -Endospores: heat-resistant resting structures with tough cell wall and spore coat. can survive harsh conditions because it is dormant

9. Small size hampers study. Much learned by using advanced microscopy techniques and from growing bacteria in pure cultures. Taxonomy of prokaryotes: Shape Color Motility Nutrition Antibiotic sensitivity Gram stain reaction Constructions of classification schemes that reflect evolution are recent.

10.  rRNA is evolutionarily ancient  All free-living organisms have rRNA  rRNA has the same role in translation in all organisms; lateral transfer is unlikely  rRNA has evolved slowly; sequence similarities are easily found  Photoheterotrophs  Photoautotrophs  Chemoheterotrophs  Chemolithotrophs Evolutionary studies and Nucleotide sequencing of ribosomal RNA :

11. Archaea = Extremeophiles High salinity High Temp High or low pH Low O 2 Archaea = Mesophiles soil Grouping Names Euryarcheota, Crenarcheota, Korarchaeota and Nanoarchaeota

12. Prokaryotes are a part of all ecosystems. Only a small minority are human pathogens (disease-causing organisms). Many species play many positive roles in such diverse applications as cheese making, sewage treatment, and production of antibiotics, vitamins, and chemicals. Plants depend on prokaryotes for their nutrition, for processes such as nitrogen fixation and nutrient cycling.

13. Berenbaum, May R. "Chapter 26: Bacteria and Archaea." Life: The Science of Biology, Ninth Edition. By H. Craig. Heller, David M. Hillis, and David Sadava. Sunderland, MA,: Sinauer Ass., W.H. Freeman and, 2011. N. pag. Print"HowStuffWorks "Science"" HowStuffWorks. N.p., n.d. Web. 10 Oct. 2012.. "Wikipedia." Wikipedia. Wikimedia Foundation, 10 Sept. 2012. Web. 10 Oct. 2012..