Exam 2 Prep Work

• Chemoheterotrophs

  • Source of carbon: carbon
  • Source of energy: carbon
• Saprophyte

  Chemoheterotroph

  Source of C and E: dead matter
• Parasite

  Chemoheterotroph

  Source of C and E: living matter
• Glycolysis

  • Embden Meyehoff Pathway
  • Preparatory Stage: processing of glucose (adding phosphate groups: cost ATP)
  • Conversion to Pyruvate
  • Net Gain: 2 ATP and 2 NADH
• Alternatives to Glycolysis

  • Pentose phosphate
  • Entner Doudoroff
• Pentose Phosphate

  • Produce NADPH and H+
  • Aerobic and anaerobic
• Entner Doudoroff

  • Uses 1 ATP
  • 2-keto-3-deoxy-6-phosphogluconic acid
  • gram negative bacteria
• Photophosphorylation

  • cyclic: need light energy
  • non-cyclic: generates oxygen gas, needs water
• Calvin Benson Cycle

  • End product: glucose
  • Carbon "fixation"
  • Needs 18 ATP and 12 NADPH
• Respiration

  aerobic process
• Fermentation

  • anaerobic process
  • pyruvate degraded to form organic products such as ethanol or acids
• Cellular respiration

  • Aerobic: Krebs cycle
  • Anaerobic: nitrate or sulfate
• Chemiosmosis

  • electrons generate proton gradient
  • protons flow across membrane
  • uses ATPase running backwards to generate energy
  • alpha proteobacteria
• Proton Motive Force

  • create proton gradient
  • protons pumped across membrane with oxidation of carriers (NADH, NADPH, FADH2)
  • protons flow through F1F0 ATPase
  • 2 or 3 H+ = 1 ATP
  • studied using uncouplers (ionophores)
• Escherichia Coli Electron Transport

  • uses NADH, FADH2
  • 5 cytochromes, based on PO2
  • TEA: oxygen
  • 1.3 P/O ratio
• Paracoccus Denitrification Electron Transport

  • heterotrophically or autotrophically
  • autotrophy: uses H2, CO2, NO2
  • NO2 reduced to N2
• Chemoautotrophs

  • Source of carbon: carbon dioxide fixation
  • Source of energy: oxidation
  • lithotrophy, nitrifiers, sulfur oxidizers
• Lithotrophy

  • oxidation of inorganic molecules producing energy
• Nitrifiers

  • convert reduced ammonium to nitrite: nitrosomonas, nitrosospira
  • further oxidized to nitrate: nitrobacter or nitrococcus
• Sulfur oxidizers

  • oxidize sulfur, hydrogen sulfide, thiosulfate
  • Thiobacillus: low pH optimum
• Photoautotrophy

  • Source of carbon: carbon dioxide
  • Source of energy: sunlight
• Oxygenic photoautotrophs

  • Non-cyclic photophosphorylation: release O2
  • Cyanobacteria, green algae
• Anoxygenic photoautotrophs

  • Cyclic photophosphorylatation
  • Electron donor: sulfur
  • Green and purple bacteria
• Photoheterotrophy

  • Source of carbon: other
  • Source of energy: light
• Rhodopseudomonas

  purple non-sulfur bacteria
• Chloroflexus

  green non-sulfur bacteria
• Earth cooled

  4.6 bya
• First unicellular life form

  • stromatolites
  • 3.5 bya
• Clear microbe fossil

  2 bya
• First eukaryotic cell

  • Endosymbiont: nucleus, mitochondria, chloroplasts
  • 1.4 bya
• Microbial taxonomy

  • Classified by Linnaean system, Carolus Linnaeus
• 3 domains

  Archaea, Bacteria, Eukarya

  work of Carl Woese
• Archaea

  2 biggest family: Crenarchaeota and Euryarchaeota
• Thermoacidophiles

  • no cell wall
  • 3 genera
• Extreme thermophiles

  • pyrococcus
  • paleococcus
  • thermococcus
  • reduce sulfur to sulfide
• Extreme halophiles

  • class halobacteria
  • 15 genera
  • 1.5 M NaCl to grow
• Halobacterium salinarum

  • photosynthetic
  • no chlorophyll
  • purple membrane
  • bacteriorhodopsin
• Methanogens

  • obligate anaerobes
  • start from CO2, H2
  • 5 orders: 27 genera
  • Ecology: lake beds, deep ocean sediments, animal intestines
• Archaea cell envelope

  • ether-linked lipids
  • pseudomurein (like peptidoglycan)
• Pseudomurein

  • N-acetyltalosaminuronic acid
  • Beta glycosidic bond
  • Different peptide junctions
  • branched