4.12 Catabolic Diversity Microorganisms demonstrate a wide range of mechanisms for generating energy (Figure 4.22) – Fermentation – Aerobic respiration – Anaerobic respiration – Chemolithotrophy – Phototrophy © 2012 Pearson Education, Inc.

4.8 Glycolysis Glycolysis – Glucose consumed – Two ATPs produced – Two reduced NADH + H+ – Fermentation products generated Some harnessed by humans for consumption © 2012 Pearson Education, Inc.

14.1 Energetic and Redox Considerations In the absence of external electron acceptors, compounds can be fermented (Figure 14.1) – ATP is usually synthesized by substrate-level phosphorylation Energy-rich phosphate bonds from phosphorylated organic intermediates transferred to ADP Redox balance is achieved by production of fermentation products © 2012 Pearson Education, Inc.

Figure 4.12 Phosphoenolpyruvate Adenosine triphosphate (ATP) (ATP)Glucose 6-phosphate Acetyl-CoA Acetyl phosphate Anhydride bond Anhydride bonds Anhydride bond Ester bond Thioester bond Acetyl Coenzyme A © 2012 Pearson Education, Inc.

Figure 14.2 Formate hydrogenlyase Hydrogenase © 2012 Pearson Education, Inc.

Figure 4.10 NAD  NADH  H  Nicotinamide Adenine NAD  / NADH E 0  0.32V © 2012 Pearson Education, Inc.

Figure 4.14 Stage I Stage II Stage III Glucose Pyruvate 2 Pyruvate 2 lactate 2 ethanol  2 CO 2 Energetics Yeast Lactic acid bacteria Intermediates Glucose 6-P Fructose 6-P Fructose 1,6-P Dihydroxyacetone-P Glyceraldehyde-3-P 1,3-Bisphosphoglycerate 3-P-Glycerate 2-P-Glycerate Phosphoenolpyruvate Enzymes Hexokinase Isomerase Phosphofructokinase Aldolase Triosephosphate isomerase Glyceraldehyde-3-P dehydrogenase Phosphoglycerokinase Phosphoglyceromutase Enolase Pyruvate kinase Lactate dehydrogenase Pyruvate decarboxylase Alcohol dehydrogenase © 2012 Pearson Education, Inc.

I. Fermentation 14.1 Energetic and Redox Considerations 14.2 Lactic and Mixed-Acid Fermentations 14.3 Clostridial and Propionic Acid Fermentations 14.4 Fermentations Lacking Substrate-Level Phosphorylation 14.5 Syntrophy © 2012 Pearson Education, Inc.

14.2 Lactic and Mixed-Acid Fermentations Fermentations are classified by either the substrate fermented or the products formed A wide variety of organic compounds can be fermented – Lactic acid bacteria produce lactic acid – Lactic acid fermentation can occur by homofermentative (Figure 14.3a) and heterofermentative (Figure 14.3b) pathways © 2012 Pearson Education, Inc.

Figure 14.3a Glucose Homofermentative Fructose 1,6 -bisphosphate 2 Glyceraldehyde 3-phosphate (G3-P) Dihydroxyacetone phosphate 2 1,3-Bisphospho- glyceric acid 2 Pyruvate 2 Lactate Aldolase Glucose  2 lactate   2H +  G 0   196 kJ (C 6 H 12 O 6 ) 2(C 3 H 5 O 3  ) (2 ATP) © 2012 Pearson Education, Inc.

Figure 14.3b Glucose Heterofermentative Ethanol Acetaldehyde Acetyl phosphate Glycer- aldehyde 3-P Xylulose 5-phosphate Ribulose 5-phosphate  CO 2 6-Phosphogluconic acid Glucose 6-phosphate Phospho- ketolase Pyruvate - 1,3-Bisphospho- glyceric acid Glucose  lactate   ethanol  CO 2  H +  G 0   216 kJ (C 6 H 12 O 6 ) (C 3 H 5 O 3  ) (C 2 H 5 OH) (1 ATP) Lactate © 2012 Pearson Education, Inc.

14.2 Lactic and Mixed-Acid Fermentations The Entner–Doudoroff Pathway – A variant of the glycolytic pathway – Glucose 6-phosphate converted to pyruvate and glyceraldehyde 3-phosphate – Yields half the ATP of glycolysis – A widespread pathway for sugar catabolism in bacteria © 2012 Pearson Education, Inc.

Figure 14.4 Glucose Glycolysis Lactate Formate Succinate Ethanol Pyruvate Thiamine pyrophosphate (TPP) Pyruvate   -Acetolactate Acetoin 2,3-Butanediol Overall reaction: 2 Pyruvate  NADH  2 CO 2  butanediol Mixed-acid route, e.g., Escherichia coli Butanediol route, e.g., Enterobacter aerogenes © 2012 Pearson Education, Inc.

14.3 Clostridial and Propionic Acid Fermentations Secondary fermentation – The fermentation of fermentation products – Fermentation of ethanol plus acetate by Clostridium kluyveri Propionic acid fermentation (Figure 14.7) – Propionibacterium and related prokaryotes produce propionic acid as a major fermentation product © 2012 Pearson Education, Inc.

Review for Exam Metabolism coupled chemical reactions for all Cell Catabolism: Chemical reactions that degrading chemicals to produce energy, exergonic Anabolism: biosynthesis, requires ATP & reducing power to proceed. Catabolism/anabolism are coupled

Thermodynamics Glucose  2carbon dioxide + 2ethyl alcohol + 56kcal ΔH= ΔF –TAS ATP discrete packets of energy available for work Catabolism/ Anabolism: coupled

List Three ways cells make ATP Substrate level phosphorylation Respiration (aerobic/anarobic) PMF ATPase Photophosphorylation

Oxidation/Reduction Define oxidation Define reduction Redox potential Oxidation states of an element What does it mean when an oxidation happens a reduction must happen, can an electron ever be “alone” What is an electron pair?

Types of Metabolism Fermentation, Respiration aerobic & anaerobic, Photosynthesis Glycolysis (EMP) List products,type ATPproduced Acetyl CoA, TCA Cycle, List products Oxidative Pentose Phosphate Pathway, NEW! Essential for essential building products, We will explain

Sum 0f Energy Explain how much energy is produced from SLP & Respiration during aerobic respiration of one mole of glucose by a chemoheterophic bacteria Explain the chemiosomotic Hypothesis Using the following equation ΔG = -(nF)(Ehº)

Functional Froups Amide, Methyl, phosphate, sulfate,hydroxyl, carbonyl (ketone, aldehyde), carboxyl, sulfhydral & bisulfide bond, ester bond, ether bond Oxidation states of various N & S elements

Metabolic classes of metabolism Chemoheterotrophs Chemolithotrophs Phototrophs (photoheterotrophs, phoroautotrophs

11-12 precursors intermediate metablism Glycolysis 6 GP6,F6P,G3P,PGA,PEP,PYR AA, Cell wall, glycogen,LPS Acetyl COA lipids TCA 3 SCA,2KA, OXA (AA, tetrapyrooles, nucleotides) Pentose Phosphate Pathway: Glucose-----  CO2, NADPH, R-5P, E-4P

Pentose Phosphate Pathway Intermediate metabolism for synthesis Glycolysis AcetylCoA TCA Pentose Phosphate Pathway

Glucose---  Carbon Dioxide, NADPH, ribulose-5-P & Erythrose-4-P (two precursors for Synthesis of Macromolecules) R-5-P also important for non-oxidative of all carbohydrates

Pentose Phosphate Pathway

Enzyme substrate Complex

Enzyme Structure