chapter five: microbial metabolism

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chapter fivemicrobial metabolism
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oxidation-reduction

• redox reaction coupled reactions

e- removed as part of H atom
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redox reactions
aerobic respiration
oxygenic photosynthesis
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nutritional classification metabolic strategy
carbon source organic vs. CO2
heterotroph
autotroph
energy source light/chemical
energy source light/chemical
photoheterotroph
chemoheterotroph
photoautotroph
chemoautotroph
electron source organic/inorganic
electron source inorganic
electron source organic/inorganic
electron source organic/inorganic
photoorgano- heterotroph
photolitho- heterotroph
photolitho- autotroph
chemoorgano- heterotroph
chemoorgano- autotroph
chemolitho- heterotroph
chemolitho- autotroph
electron acceptor organic/inorganic
O2 vs. inorganic
fermentation
respiration O2 vs. other
oxygenic photosynthesis
anoxygenic photosynthesis
aerobic respiration
anaerobic respiration
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classifying respiration photosynthesis
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complementary metabolism
autotrophy heterotrophy
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acquiring energy substrate level phosphorylation
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acquiring energy oxidative phosphorylation
chemiosmosis
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heterotrophy respiration
NO2-, N2 H2O H2S H2O CH4 H2O H2O
NO3- SO4- CO32- O2
cell material
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heterotrophy respiration fermentation
lactic acid ethanol CO2 mixed acids butanediol
organic pyruvate
ferm
cell material
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heterotrophy respiration fermentation

• respiration
• inorganic e- acceptor
• does NOT mean O2
• organic mole. ? CO2
• fermentation
• organic e- acceptor
• organic ? organic mole.
• incomplete H stripping,lower ATP yield

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metabolism media
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Chapter Five Learning Objectives

• Discuss redox reactions in biological systems.
• Identify the redox partners in aerobic and
  anaerobic respiration and oxygenic and anoxygenic
  photosynthesis.
• Correctly identify the carbon, energy and
  electron source for an organism when given its
  nutritional classification (e.g.,
  chemoorganoheterotroph).
• How is ATP generated in both substrate level and
  oxidative phosphorylation?
• Why is it so important that the electron
  transport chain is housed in a lipid bilayer
  membrane? Why is a terminal electron acceptor so
  important?
• What happens in a microorganism if the terminal
  electron acceptor of the ETC is not available?
  What molecules build up? What is done with these
  molecules?
• How do amphibolism, catabolism and anabolism
  relate to growth and repair in cells?
• Discuss the major differences between respiration
  and fermentation. What are the four basic kinds
  of fermentation?

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autotrophy chemosynthesis

• chemo- conversion of chemical E ? ATP
• sulfur oxidation
• iron oxidation
• -synthesis carbon fixation (CO2 ? organic
  molecule)

2 H
2Fe2
2Fe3
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chemosynthesis iron oxidation

• Thiobacillus ferrooxidans
• chemolithoautotrophy
• energy Fe2 ? Fe3
• electron same
• carbon CO2 ? CH2O

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chemosynthesis sulfur oxidation

• Sulfolobus acidocaldarius
• chemolithoautotrophy
• energy S2- (sulfide) / S2O32- (thiosulfate)
• ? SO32- (sulfite)
• electron same
• carbon CO2 ? CH2O

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autotrophy photosynthesis

• photo light E ? chemical E
• light-dependent (light) reactions
• ATP NAD(P)H reducing power
• synthesis
• light-independent (dark) reactions
• carbon fixation piling e- onto CO2

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photosynthetic electron flow chemiosmosis
cyclic photosynthesis in the purple sulfur
bacteria
non-cyclic photosynthesis in the cyanobacteria
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microbial CO2 fixation
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photosynthesis compared
O2
H2S
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chapter 5 learning objectives

• How is ATP generated in chemosynthesis,
  photosynthesis and respiration? How is the
  process different for each and how is it the
  same?
• Discuss the redox partners of sulfur and iron
  oxidizing bacteria.
• How do non-cyclic and cyclic photosynthesis
  differ? How does each produce ATP and
  NADPH/NADH? What is each used for?
• How is carbon fixed during chemosynthesis and
  photosynthesis? How is the process similar and
  how is it different?

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chapter fivemicrobial metabolism