metabolism. chapter 5 why study metabolism? classification of bacteria –oxygen tolerance...
TRANSCRIPT
Metabolism
Chapter 5
Why Study Metabolism?• Classification of bacteria
– Oxygen Tolerance– Biochemical reactions
• Acids, Ammonia, Gases
• Fermentation Products– Food Products
• Yogurt, Sour Cream, Bread, Alcohol
– Commercial Products• Citric Acid, Plastics
• Environmental Cleanup
Chapter 5
Ying & Yang of Metabolism• Metabolism = Anabolism + Catabolism
• Photosynthesis requires Respiration
• Respiration requires Photosynthesis
• Energy Production = Energy Consumption
Chapter 5
BreakdownProteins to Amino Acids, Starch to Glucose
SynthesisAmino Acids to Proteins, Glucose to Starch
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Overview of Metabolism• Source of Energy (Photo- vs.
Chemotroph)– Source of Electrons– Carrier of Electrons– Final Electron Acceptor
• Source of Carbon (Auto- vs. Heterotroph)– Auto- : Carbon Dioxide– Hetero- : Organic Compounds
Chapter 5
Classification based on Metabolism• Where microbes get their energy?
– Sunlight vs. Chemical– Photo- vs. Chemo- trophs
• How do they obtain carbon?– Carbon Dioxide (or inorganic cmpds.) vs.
Organic Compounds (sugars, amino acids)– Auto- vs. Hetero- trophs
• Examples– Photoautotrophs vs. Photoheterotrophs– Chemoautotrophs vs. Chemoheterotrophs
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Types of -trophsType Energy C source Example
Photoauto- Sun CO2 Purple &Green sulfurbacteria
Photohetero- Sun OrganicCompounds
Purple &Green Non-sulfur bacteria
Chemoauto- Chemicalbonds
CO2 H, S, Fe, Nbacteria
Chemohetero- Chemicalbonds
OrganicCompounds
Most bacteria,fungi,protozoa,animals
Chapter 5
Source of Electrons• Autotrophs
– Photosynthesis
– H2O, H2S
• Chemotrophs– Organic Compounds
– Carbohydrates (C H2O)• Glucose, Lactose, Sucrose, Mannitol, Citrate
– Amino Acids
Chapter 5
Electron Carriers• Photosynthesis
– NADP + H to NADPH
• Respiration– NAD + H to NADH– FAD + H to FADH
• Contain Niacin and Riboflavin– Vitamins, not stable– Can’t store these molecules
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Final Electron Acceptor• Photosynthesis
– CO2 + H’s to CH2O
– Stores energy
• Respiration– Aerobic
• 1/2 O2 + H 2 to H2O
– Anaerobic• Fermentation
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Movement of Electrons• Chemical reactions
• Oxidation Reactions
• Reduction Reactions
• Reactions Coupled– Redox reactions
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Example of Redox Equations
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Example of Redox Equations
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Example of Redox Equations
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Examples• ATP ADP + P
– Oxidation, release energy
• ADP + P ATP– Reduction, stores energy
• NAD + H NADH
• FADH FAD + H
• NH4 + 11/2O2 NO2
- +H2O + 2H + ATP
• 2H2 + O2 2H2 O
Chapter 5
Examples• Cellular Respiration
– C6H12 O6 + 6O2 6H2O + 6CO2 + 38 ATP
• Photosynthesis– 6H2O + 6CO2 + light C6H12 O6 + 6O2
• Nitrification– NH4 NO2 to NO3
• Ammonia to Nitrite to Nitrate
• Ammonification– N2 NH4
Chapter 5
Respiration• Overview;
– Glucose to Carbon dioxide + Water +Energy
– C6H12O6 + O2 6CO2 + 6H2O + 38 ATP
– Glucose is highly reduced; contains energy– Oxygen receives the electrons to form
energy
• 4 separate reactions– Glycolysis, Transition Reaction, Krebs
Cycle, Electron Transport, Chemiosomosis
• Requires Oxygen
Chapter 5
Steps in Respiration• Electron Donors
– Organic Compounds (Glucose preferred)
• Electron Carriers– NAD to NADH– FAD to FADH
• Electron Acceptors-Terminal– O2 to H2O
• Phosphorylation Reactions– ADP to ATP
• Chemiosmosis Reactions
Chapter 5
Glycolysis- 10 steps• Glucose is Phosphorylated to form
Fructose 1,6-diphosphate
• Split to form 2 Glyceraldehyde 3-phosphate
• Final Products are:– 2 Pyruvic Acid (C3H4O3)
• Compare to original glucose - C6H12O6
– 2 NADH– 2 ATP
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Transition Reaction• Pyruvic Acid Acetyl - Co A + CO2 +
NADH
• C2H4O2
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Kreb’s Cycle• Figure E.3, A29
• Acetyl CoA Carbon Dioxide– C2H4O2 to CO2
– Energy produced/Acetyl CoA (x2 for /Glucose)
• 3 NADH• 1 FADH• 1 ATP
• Metabolic Wheel– Fats, amino acids, etc. enter or leave– Citrate is product of first reaction
• Simmons Citrate Media
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Electron Transport Chain• NADH oxidized to NAD
• FAD reduced to FADH
• Cytochromes shuffle electrons finally to O2
– Cytochrome Oxidase important in G - ID
• H2O formed and ATP
• 3 ATP / 1 NADH
• 2 ATP / 1 FADH
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Fermentation Products from Pyruvate
• Homolactic = Lactic Acid– Yogurt, Lactobacillus
• Alcohol + CO2
• Propionic Acid
• Butyric Acid
• Acetic Acid
• Succinic Acid
• Butylene to Acetoin– basis for VP Test (Vogues-Proskauer)
Chapter 5
Fermentation Products• Alcohol and Carbon Dioxide
– Yeast mostly
• Lactic Acid– Humans, muscles without oxygen– Bacteria (Lactobacillus-yogurt)
• Butyric Acid– Rancid butter, Clostridium-gangrene
• Acetoin – Butanediol fermentation in Klebsiella
• Propionic Acid – Swiss Cheese
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Fermentation in Yeast
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Fermentation in Muscle
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Photosynthesis
• Plants– CO2 + H2O + Light C6H12O6 + O2
– Water is split to release electrons
• Bacteria– H2S is used not water
• Sulfur or Sulfuric Acid formed• Oxygen not released
– Chlorophyll is different– Strict Anaerobe– Purple & Green Sulfur Bacteria
Chapter 5
Chemiosmosis• Production of ATP in Electron Transport
• Electrochemical Gradient Formed between membranes
• H+ (Protons) generated from NADH
• Electrical Force (+) & pH Force (Acid)
• Gradient formed
• ATPase enzyme that channels H+ from High to Low concentration– 3 ATP/NADH– 2 ATP/NADH
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Summary of Respiration• Aerobic Respiration
– Glycolysis– Transition Rx.– Kreb’s Cycle– Electron Transport
Chain
• Anaerobic Respiration– Pyruvate
• Lactic Acid• Mixed Acids• Alcohol + CO2
– Recycle NADH– 2 ATP / Glucose