Metabolism

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Metabolism

• Nutrition
• 2. Respiration
• 3. Winogradsky Column

2
Nutrition

• 1. Photoautotrophs
• 2. Chemoautotrophs
• 3. Photoheterotrophs
• 4. Chemoheterotrophs

3
Photoautotrophs

• 1. Obtain energy from sunlight
• 2. Use energy to synthesize cellular compounds
  from CO2
• 3. Plants, algae, cyanobacteria produce O2
• 4. Green sulfur purple sulfur bacteria
  anoxygenic

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Chemoautotrophs

• 1. Obtain energy from oxidation of inorganic or
  organic compounds
• 2. Use energy to synthesize cellular compounds
  from CO2
• 3. Sulfur oxidizing nitrogen oxidizing bacteria

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Photoheterotrophs

• 1. Obtain energy from sunlight
• 2. Use energy to synthesize cellular compounds
  from organic compounds
• 3. Purple nonsulfur bacteria, sheathed bacteria

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Chemoheterotrophs

• 1. Obtain energy from oxidation of inorganic or
  organic compounds
• 2. Use energy to synthesize cellular compounds
  from organic compounds
• 3. Animals, fungi, glucose ferment bacteria,
  sulfur reducing bacteria

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Respiration

• 1. External- breathing, movement of O2 into CO2
  out of organism
• 2. Internal- cellular, exothermic breakdown of
  molecule to harvest energy
• 3. Aerobic, anaerobic, fermentation

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Aerobic Respiration

• 1. Complete oxidation of inorganic or organic
  molecules to harvest their energy
• 2. Inorganic molecules
• 3. Organic molecules

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Inorganic Molecules

• 1. Hydrogen sulfide oxidizing bacteria-
• 2H2S 5O2 g 2SO4-2 2H2O E
• 2. Ammonium oxidizing bacteria-
• 2NH4 5O2 g 2NO3- 4H2O E

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Organic Molecules

• 1. Some bacteria mitochondria of eukaryotes
  oxidize glucose to CO2
• C6H12O6 6O2 g 6CO2 6H2O
• 3. Methylocystis sp other bacteria oxidize
  methane to carbon dioxide
• CH4 2O2 g CO2 2H2O

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Eukaryote Respiration

• 1. Glycolysis
• 2. Transition Reaction
• 3. Citric Acid Cycle
• 4. Electron Transport System (ETS)

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Glycolysis 1

• 1. Occurs in cytoplasm
• 2. Reactants- C6H12O6 2NAD 2ATP 4ADP
  2PO4-3
• 3. Products- 2C3H4O3 2NADH 4ATP
• 4. C3H4O3 to transition rxn, NADH to ETS, ATP to
  cytoplasm

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Glycolysis 2

• 1. Oxygen independent, anaerobic
• 2. If O2 present, proceeds to mitochondria
• 3. If O2 absent, proceeds to
• fermentation
• C6H12O6 2ATP g 2C3H4O3 4ATP
• Pyruvic acid

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Mitochondrion Description

• 1. Bilayer membrane with intermembrane space,
  1-5mm
• 2. Cristae- folds of inner membrane project into
  matrix, ETS
• 3. Matrix- innermost compartment filled with
  gel-like fluid, transition rxn citric acid cycle

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Mitochondrion Structure
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Transition Reaction

• 1. Occurs in mitochondria
• 2. Reactants- 2C3H4O3 2NAD 2CoA
• 3. Products- 2acetylCoA 2NADH 2CO2
• 4. AcetylCoA to citric acid cycle, NADH to ETS,
  CO2 to cytoplasm exits the cell

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Citric Acid Cycle 1

• 1. Occurs in mitochondria
• 2. Reactants- 2acetylCoA 6NAD 2FAD 2ADP
  PO4-3
• 3. Products- 6NADH 2FADH2 2ATP 4CO2
• 4. NADH FADH2 to ETS, ATP to cytoplasm, CO2 to
  cytoplasm exits the cell

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Citric Acid Cycle 2
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ETS 1

• 1. Occurs in mitochondria
• 2. Reactants- 10 NADH 2FADH2 O2
• 3. Products- 10 NAD 2FAD 32 to 34 ATP H2O
• 4. NAD to glycolysis, transition rxn, or citric
  acid cycle FAD to citric acid cycle ATP H2O
  to cytoplasm

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ETS 2

• 1. Oxidative phosphorylation
• 2. Mediated by flavins cytochromes
• 3. Overall rxn
• FADH2 NADH O2 -gt 34 ATP H2O

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Glucose to ATP
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Anaerobic Respiration

• 1. Complete oxidation of organic compounds to CO2
  or complete oxidation of inorganic compounds
  using oxidizers other than oxygen
• 2. Desulfovibrio sp oxidize acetic acid to CO2
  using SO4-2
• C2H4O2 H2SO4 H2O g 2CO2 H2S 3H2O

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Fermentation 1

• 1. Incomplete oxidation of organic compound to
  CO2 another organic compound
• 2. Saccharomyces cerevisiae ferment glucose to
  CO2 ethanol
• C6H12O6 g 2CO2 2C2H5OH

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Fermentation 2

• 1. Alcoholic Fermentation
• 2. Lactic Acid Fermentation
• 3. Both produce no ATP but regenerate NAD for
  glycolysis

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Alcoholic Fermentation

• 1. In cytoplasm of plant cells and yeast cells
• 2. Beer and bread yeast
• C3H4O3 NADH g CO2 C2H5OH NAD
• 
  Ethanol
• (Ethyl
  alcohol)

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Lactic Acid Fermentation

• 1. In cytoplasm of muscle cells, oxygen debt
• 2. Sour milk bacteria, yogurt, pasteurization
• C3H4O3 NADH g C3H6O3 NAD
• Lactic Acid

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Prokaryote Metabolism

• 1. More metabolic pathways than other four
  kingdoms
• 2. Recycle all mineral elements organic
  compounds required for life
• 3. Metabolic activities of one group allow
  another group to live
• 4. M. W. Beijerinck (1851-1931) S. N.
  Winogradsky (1856-1953)- relationships between
  different microbes in mixed communities

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Winogradsky Column

• 1. Clear tube, 30cm x 5cm diameter
• 2. Lower 1/3- lake or river bottom mud plus
  cellulose, Na2SO4, CaCO3
• 3. Upper 2/3- water from mud source
• 4. Cap tube and place in sun or full spectrum
  light

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Winogradsky Column
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Winogradsky Incubation

• 1. Two to 3 months
• 2. Added cellulose promotes rapid microbial
  growth
• 3. Microbes deplete O2 in sediment water
• 4. O2 diffusion from air oxygenates top water
  level

31
Winogradsky Levels

• 1. All organisms initially present in numbers
• 2. Different microbes multiply occupy different
  levels
• 3. Levels- specific environmental conditions that
  support specific organisms metabolic pathway

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Fermentative Chemoheterotrophs

• 1. Glucose fermenting bacteria, Clostridium sp,
  break dormancy grow with anaerobic conditions
• 2. Breakdown cellulose to glucose
• 3. Ferment glucose to ethanol, acetic acid,
  succinic acid . . .

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Anaerobic Chemoautotrophs

• 1. Sulfur reducing bacteria, Desulfovibrio sp
• 2. Oxidize glucose fermentation products to CO2
  using SO4-2 or S2O3-2
• 3. SO4-2 S2O3-2 reduced to H2S

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Anaerobic Photoautotrophs

• 1. Green sulfur purple sulfur bacteria,
  anaerobic photosynthesis
• 2. Right below water-sediment interface
• 3. Synthesize glucose from CO2 H2S using light
  energy
• 6CO2 12H2S g C6H12O6 6H2O 12S

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Green Sulfur Bacteria

• 1. Lower level, smaller than purple sulfur
  bacteria
• 2. Usually deposit sulfur externally
• 3. Chlorobium sp

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Purple Sulfur Bacteria

• 1. Upper level, larger than green sulfur bacteria
  
• 2. Deposit sulfur internally
• 3. Thiocapsa sp

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Anaerobic Photoheterotrophs

• 1. Purple nonsulfur bacteria, synthesize cellular
  compounds from organic acids using light
• 2. Rhodopseudomonas, Rhodospirillum,
  Rhodomicrobium genera
• 3. Intolerant of H2S, so found above green
  purple sulfur bacteria
• 4. Intolerant of O2, so when cyanobacteria
  oxygenate water column

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Aerobic Chemoautotrophs

• 1. Sulfur oxidizing bacteria
• 2. Oxidize H2S to SO4-2 for energy
• 3. Synthesize cellular compounds from CO2
• 4. Soil aerobic chemoautotrophs oxidize NH4 to
  NO3-

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Aerobic Photoautotrophs

• 1. Cyanobacteria synthesize glucose from CO2
  H2O using light energy
• 2. Like plants algae, but no chloroplasts
• 3. Only oxygen producing bacteria

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Aerobic Photoheterotrophs

• 1. Sheathed bacteria synthesize cellular
  compounds from organic compounds
• 2. Sheath- rigid tube of protein, polysaccharide,
  lipid
• 3. Fe(OH)3 gives yellow to rusty color
• 4. Sheath surrounds chain of bacteria, bacterium
  swim free to form new colonies

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