Microbial

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Microbial
Metabolism
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Metabolism

• Metabolism
• Catabolism Anabolism
• Driven by energy, ATP

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ATP

• Nucleic acid base - adenine
• 5 carbon sugar - ribose
• 3 phosphate groups- aligned
• 2nd and 3rd bonds are high energy
• Can add and remove phosphate groups

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Enzymes

• Catalytic Proteins
• Substrate(s)
• Coenzymes
• lock and key function

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Enzymes

• Catalytic Proteins
• Re-useable
• Active site
• lock and key function

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Enzyme Catalysis

• Optimum temperature
• Optimum pH
• Optimum substrate

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Enzyme Denaturation

• Proteins have 3D structure (lock)
• Destruction of 3D structure destroys
  functionality
• Denature by
• heat,
• pH,
• solvents -alcohol, acetone, etc
• chemicals, oxidizers, aldehydes, etc

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Control of Enzymes

• Competitive Inhibitors
• Non-competitive (feedback) inhibitor
• Gene expression

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Feedback of Enzymes

• Occurs in a metabolic pathway
• Pathway is usually anabolic
• End products of pathway inhibit enzymes at the
  beginning (feedback).
• Prevent over-production.
• Conserve energy, resources.

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Oxidation - Reduction

• Reduction- gain of electrons or hydrogens loss of
  oxygen
• Oxidation - loss of electrons or hydrogens gain
  of oxygen
• One chemical gains - one loses e-.or hydrogens
• Must have both reactions

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Ways to make ATP

• Substrate level phosphorylation - requires
  another high energy compound.
• Oxidative phosphorylation - uses high energy
  electrons and an electron transport system
• Photophosphorylation - uses light as energy
  source.

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Respiration vs Fermentation

• No oxygen present in fermentation.
• More ATP produced (38 vs 2 ).
• Carbon compound is the final electron acceptor,
  not O2.

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Glycolysis -EMP

• Glucose- 6C sugar
• Use 2 ATP to kick-start
• Split into 2 3C molecules
• Reduce NAD to make NADH2
• Make 2 ATP.

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Glycolysis -EMP

• Reduce NAD
• Make 2 ATP.
• Make high energy PEP
• Make 2 more ATP
• Net Gain 2 ATP

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Krebs (TCA) Cycle

• Pyruvate converted to AcetylCoA 1 NADH2
• AcCoA condensed with oxalacetate (OAA) to make
  citric acid.
• Acids -decarboxylated to extract energy.
• 4 NADH2 made ATP CO2.
• Final product OAA.
• Besides energy- acids used for carbon skeletons.

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Electron Transport Chain

• Every NADH produces 3 ATP
• Every FADH2 produces 2 ATP
• Electrons passed from one cytochrome to another -
  each extracting energy.
• Final electron acceptor is O2
• End product is H2O.

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ATP Synthase

• Protons transported across cell membrane
• ATP synthase imbedded in CM.
• As they pass back through, their energy makes
  ATP.
• Chemiosmosis

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ATP Synthase
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Overall Reactions
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Fermentation

• Glycolysis proceeds as usual.
• Pyruvic acid final product.
• Pyruvate converted to other compounds to oxidize
  NADH so glycolysis can proceed.

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Fermentation

• Pyruvate converted to lactic acid
• Pyruvate converted to ethanol

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Lipid Catabolism

• Lipid broken down to glycerol and fatty acids.
• Glycerol enters EMP.
• Fatty acids broken down 2 C at a time to make
  AcCoA.
• AcCoA enters TCA.

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Catabolism
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Photophosphorylation

• Sunlight excites chlorophyll
• Energized chlorophyll passes high energy
  electrons down electron transport.
• ATP made.

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Calvin Benson Cycle

• CO2 in.
• Energy from photophosphorylation in ATP used to
  make glucose.

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Synthesis of Carbohydrates
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Synthesis of Lipids

• Glycerol from EMP.
• Fatty Acids from AcCoA.

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Synthesis of Amino Acids

• Acids from EMP, Krebs Cycle, and ED pathways are
  transaminated.

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Transamination

• Amino group transferred from one compound to
  another.
• Reversable

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Synthesis of Nucleotides
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Integration of Metabolism