13_EnergyPath1W11_bacteria and archaea

13_EnergyPath1W11_ba - How to Eat Almost Anything Energy and Building Blocks • Energetic pathways – ATP production – Organic molecules as

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Unformatted text preview: How to Eat Almost Anything Energy and Building Blocks • Energetic pathways – ATP production – Organic molecules as building blocks • Bacteria and Archaea Eschel Ben-Jacob, Bacteria as Art http://star.tau.ac.il/~eshel/gallery.html ATP Production: Examples • Oxygenic Photosynthesis – Electron donor: H20 – Electron acceptor: NADP+ • Aerobic respiration – Electron donor: glucose or other sugars – Electron acceptor: O2 ATP Production: Examples • Nitrogen Fixing Bacteria – Electron donor: ferredoxin – Electron acceptor: N2 (from air) – Byproduct: Ammonia • Nitrogen is cycled through soils – Each type of bacteria uses byproduct of another species as electron donor Denitrification by bacteria and archaea Fixation by bacteria and archaea Decomposition Uptake from soil or seawater Uptake from soil Decomposition by bacteria, archaea, fungi Uptake from soil or seawater Nitrification by bacteria Decomposition Nitrification by bacteria and archaea Freeman 28.13 ATP Production: Examples • Sulfate reducing bacteria – Electron Donor: Organic compounds, H2 – Electron Acceptor: Sulfate, sulfide, sulfur – Generate H2S (rotten egg smell) – swamps, intestinal bacteria – typically need anaerobic environment • Sulfur oxidizing bacteria – Electron Donor: H2S – Electron acceptor: O2 (aerobic) – Fix carbon in deep sea vents Energetic Pathways • Why domination by aerobic respiration & photosynthesis? – Used by eukaryotes • Mitochondria & chloroplast endosymbionts – Oxygen very reactive • Production by chlorophyll driven photosynthesis poisoned many other organisms • In respiration, energetically favorable to use as electron acceptor Figure 28-5 Glucose Glucose Glucose Electron donor in cellular respiration e– Fumarate Nitrate e– Oxygen e– Building Blocks for Growth • Organic molecules needed for growth as “building blocks” • Two types – Autotrophs • Synthesize their own building blocks – Heterotrophs • Obtain building blocks from environment, including other organisms Energy and Building Blocks Autotroph Carbon Sources • CO2 – Examples • Photosynthetic bacteria, archaea, eukaryotes • Nitrifying bacteria • Carbon monoxide (CO) • Methane (CH4) What Are Bacteria & Archaea? • “Prokaryotes” – Old taxonomic group – Used morphological similarities – Ancestral traits, not synapomorphies – Still useful descriptive term “Prokaryotes” Bacteria Archaea Eukarya Common ancestor Ribosomes Plasmids Cytoplasm Flagellum (not all) Chromosome Plasma membrane Cell wall Figure 7-1 Prokaryotes: Cell wall • Polymers that crosslink for toughness • Most bacteria have peptidoglycan • Archaea- no peptidoglycan, but have functional equivalent Cytoplasm Plasma membrane Cell wall Figure 7-2 Prokaryotes: Cell Wall Peptidoglycan layer Plasma membrane Bacteria with outer cell wall & inner plasma membrane Prokaryotes: DNA • Single chromosome • No nuclear membrane • Plasmids – Small circle of DNA – Not part of chromosome – May be exchanged with other prokaryotes DNA Supercoiled DNA in chromosome Prokaryotes vs Eukaryotes Table 7.1 Why Archaea & Eukarya a Clade? Bacteria Archaea Common ancestor of all species living today Eukarya Prokaryotes: Ribosome • Structure of RNA small subunit of the ribosome indicates a common ancestor for Archaea & Eukarya Large subunit of ribosome Small subunit of ribosome Bacteria & Archaea: Diversity DOMAIN BACTERIA Firmicutes Spirochaetes Actinobacteria Chlamydiae Cyanobacteria PROTEOBACTERIA DOMAIN ARCHAEA KORARCHAEOTA CRENARCHAEOTA EURYARCHAEOTA DOMAIN EUKARYA Figure 28.13 Bacteria & Archaea • Shape – Spheres • “coccus” – Rods • “bacillus” – Spiral – Chains – Box • Found in 2004 • • • • • Energy pathways Size Shape Motility Ecology Variety: Shape Small Size varies The sizes of bacteria and archaea vary. Mycoplasma cells (left) are about 0.5 µm in diameter, while Thiomargarita namibiensis cells (right) are about 150 µm in diameter. Figure 28-13a Length in meters 103 101 10-1 Single 10-3 Cells 10-5 10-7 Prokaryotes Large central vacuole pushes cytoplasm to surface 102 Single Celled Eukaryotes Caulerpa Green Alga Multinucleate Ostrich Egg Animal One Nucleus Radliolarian Rhizaria Diatom Stramenopile Ostreococcus Green Alga 100 Thiomargarita namibiensis Sulfur Pearl Bacteria 10-2 Escherichia coli bacteria 10-4 “ARMAN” archaea 10-6 10-8 Variety: Motility A wide variety of bacteria and archaea use flagella (left) to power swimming movements. These cyanobacterial cells (right) move by gliding across a substrate. • Non-Motile • Motile Mobility varies – Flagella (most common) – Spiral motion of body – Gliding Figure 28-13c Variety: Ecology • Everywhere life is • Extremophiles – Many environments only habitable by Archaea & Bacteria – Extremes of temperature, salinity, acidity, alkalinity • Pathogens Bacteria DOMAIN BACTERIA • Better understood than Archaea • At least 24 Phylum level clades • We’ll look at 6 Learn Taxa at Lecture Level Firmicutes Spirochaetes Actinobacteria Chlamydiae Cyanobacteria PROTEOBACTERIA DOMAIN ARCHAEA KORARCHAEOTA CRENARCHAEOTA EURYARCHAEOTA Figure 28-17 DOMAIN EUKARYA Bacteria: Cyanobacteria • “Blue Green Algae” • Transformed the earth in PreCambrian • Photosynthetic (oxygenic) • Nitrogen fixing Nostoc species Figure 28-21 Bacteria>Cyanobacteria Bacteria: Proteobacteria • Diverse shapes, metabolism – 1200 species – Many morphologies – Many metabolic pathways Stalked bacterium Fruiting bodies • • Clade unified by RNA genes Fruiting bodies – Cooperatively form colonies – Produce spores • • • Disease – Cholera, gonorrhea Nitrogen fixing species E. coli Stalk Caulobacter crescentus Chondromyces crocatus Figure 28-23 Bacteria>Proteobacteria ...
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This note was uploaded on 02/26/2011 for the course LIFE SCI 1 taught by Professor Halpin during the Winter '11 term at UCLA.

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