Chapter 27 Prokaryotes

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Unformatted text preview: bolic cooperation Survey of Prokaryotic Diversity Based on molecular systematics *read chapter 26* section on clades Not much in fossil record or from structural comparison Nucleic acid comparisons have been used to form taxonomic groups Used small subunit rRNA - signature sequences unique to a taxonomic group -evolutionary relationships Several prokaryotes have been completely sequenced Many bacteria were more closely related to eukaryotes - domain Archea 1. Genetic diversity in prokaryotes is immense. 2. Horizontal gene transfer has been important – significant portions of genomes of many prokaryotes are mosaics of genes imported from other species. kingdom broken down into two parts -didn't include all ancestors Most Known Prokaryotes are Bacteria 5 Major Clades (or groupings) *do not need to memorize* (1) Proteobacteria (Gram-negative) (2) Clamydias urethritis - most common STD in US (3) Spirochetes - syphilis, Lyme disease (4) Gram positive bacteria Actinomycetes - tuberculosis, leprosy Streptomyces - antibiotics (streptomycin) Spore formers such as Bacillus anthracis & Clostridium botulinum (5) Cyanobacteria - only prokaryotes with plantlike oxygenic photosynthesis Proteobacteria ancestor and all its descendants Universal ancestor Domain Archaea Eukaryotes Nanoarchaeotes Crenarcaeotes Euryarchaeotes Korarchaeotes Gram-positive bacteria Cyanobacteria Spirochetes Chlamydias Epsilon Delta Gamma Beta Alpha Domain Bacteria Domain Eukarya LE 27-13 PROTEOBACTERIA CHLAMYDIAS 2.5 µm 2.5 µm Subgroup: Alpha Proteobacteria Chlamydia (arrows) Rhizobium (arrows) SPIROCHETES 1 µm 5 µm Subgroup: Beta Proteobacteria Leptospira Nitrosomonas GRAM-POSITIVE BACTERIA 2 µm Subgroup: Epsilon Proteobacteria Heliocobacter pylori 50 µm CYANOBACTERIA 5 µm 10 µm Bdellovibrio bacteriophorus Chrondromyces crocatus Mycoplasmas covering a human fibroblast cell Streptomyces Subgroup: Delta Proteobacteria Oscillatoria 1 µm 0.5 µm Chromatium 5 µm Subgroup: Gamma Proteobacteria Archaea - four major taxa (clades) (1) Euryarchaeota (2) Crenarchaeota remember for exam (3)  Korarchaeota (4) Nanoarcheota Extremophiles lovers of extreme environments Can be separated into 3 groups on environmental criteria. (1) Extreme Thermophiles - thrive in hot environments 60 - 80° C (2) Extreme Halophiles - live in high-salt environments - Great Salt Lake, Dead Sea (3) Methanogens obtain energy by using CO2 to oxidize H2 → CH4 strict anaerobes - poisoned by O2 -produce swamp gas Abundance of marine archaea live among other forms of life in more moderate habitats Methanogens & Halophiles & some Thermophiles Euryarchaeota Thermophiles comprised of mostly methanogens and halophiles; some thermophiles Crenarchaeota comprised of mainly thermophiles known as "exremophiles" (archea) Ecological Impact of Prokaryotes -nitrogen fixation and decomposition...
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This document was uploaded on 03/02/2014 for the course BIO 109 at University of Missouri-Kansas City .

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