Prokaryotes Bacteria Archaea Chapter 27 Why study these organisms Why study these organisms Biomass number of species Disease Gene cloning Bioremediation Global change Oxygen Nitrogen cycle pollution Model organisms for research Extremophiles Prokaryotic shapes What do I think you should take away from our discussion of prokaryotes Tremendous diversity that allows prokaryotes to inhabit virtually all environments Thus they posses great variations in genes and gene products that provide life essential functions in these environments Dr Carl Woese utilized rRNA sequences Dr Carl Woese utilized rRNA sequences Ribosome Bacterial Ribosome Bacterial Woese developed a taxonomy based on the genes for a component 16s rRNA of the small subunit of the 30s rRNA subunit of the bacterial ribosome 16s rRNA http www nd edu aseriann rna html A word about rRNA A word about rRNA http www biochem uwo ca meds medna rRNA html Human vs E coli Human vs 5S rRNA E coli 5S rRNA http www biochemj org bj 371 0641 3710641 pdf Woese C Kandler O Wheelis M 1990 Towards a natural system of organisms proposal for the domains Archaea Bacteria and Eucarya Proc Natl Acad Sci USA 87 12 4576 9 Fig 27 15 You are here Where do we find Where do we find bacteria archaea bacteria archaea Volcanic hot springs Archaeal Richmond Mine acidophilic nanoorganisms ARMAN Table 27 2 Table 27 2 Fig 7 1 Draw the picture and tell the story Bioluminescence Prokaryotic Features Supercoiled DNA One or more circular chromosomes Few associated proteins Nucleoid region vs nucleus FigFig 7 3 7 3 Prokaryotic Genome Prokaryotic Genome Size of genome proportional to metabolic capabilities Tremendous diversity of genes Redundancy is common Multiple chromosomes Many small extra chromosomal DNAs called plasmids Genome size metabolic capabilities Genome size metabolic capabilities Mycoplasma parasite that causes pneumonia Acquires most nutrients from the host Few enzymes ergo few genes E coli Psuedomonas Inhabits soils and humans Synthesizes almost all organic molecules Prokaryotic Genome Prokaryotic Genome Size of genome proportional to metabolic capabilities Tremendous diversity of genes Many are unique to a species Redundancy within a genome is common Multiple chromosomes are not uncommon Many small extra chromosomal DNAs called plasmids Plasmids Small number of genes Copied independently of chromosomal DNA growth May or may not be necessary for Site of antibiotic resistance Allows for lateral transfer of genes Even among different species Fig 27 8 Plasmids Fig 20 4 Lateral Gene Transfer Evidence for Lateral Gene Transfer between species 1 Stretches of DNA are more similar to those in genes of distantly related species than those more closely related 2 The proportion of G C base pairs to A T base pairs in a gene is remarkably different from the base composition in the rest of the DNA Thermotoga maritima Same habitats deep sea hydrothermal vents 25 of genome of this bacterium is closely related to genomes found in resident archaea Occur in distinctive clusters in DNA Also Evidence for prokaryotic parasites picking up genes from eukaryotic hosts Intracellular parasitic bacterium Chlamydia trachomatis Contains 35 eukaryotic genes Mechanism Fig 27 12Bacterial Conjugation What we are doing Table 27 2 Differences among organisms of the three Kingdoms Bacteria and Archaea Why we study them Structure Genetic diversity how it is generated and what are the consequences See especially lateral gene transfer Summary Characterized Prokaryotes Eukarotes Archaea Table 27 2 Note mechanisms of generating diversity Moving into Prokaryotic Diversity in prokaryotes Morphological Metabolic Photosynthesis ETC Photosynthesis ETC Other Prokaryotic Characteristics Lack of compartmentalization or Organelles Little cytoskeleton Recent discovery of any cytoskeletal elements Protein FtsZ Protein FtsZ http www umass edu microbio chime pipe ftsz present ftszinvivo htm Organization and function of FstZ filaments in eubacteria McIntosh J R et al J Cell Sci 2010 123 3425 3434 Fig 27 6 Bacterial Flagellum Increased membrane surface area Table 5 1c Cellulose Peptidoglycan Bacterial Cell Walls Peptidoglycan Bacterial Cell Walls Fig 28 14 Fig 28 14 Things to know to this point Table differences among 3 major groups of organisms Mechanisms for generating genetic diversity in Archaea and Prokaryotes Types and structures of carbohydrates in extracellular cell walls rRNA FtsZ I am pulling this stuff right out of your textbook
View Full Document
Unlocking...