Microbial Metabolism_Ctecksbs

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Presentation Description

Metabolism, Metabolic Reactions, Characteristics of Anabolic Reactions, Basis of These Reactions, Reduction, Oxidation


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Microbial Metabolism:

Microbial Metabolism Part 1 www.cteck-sbs.org Expert Education Endeavor in Science

What is Metabolism?:

What is Metabolism? Metabolism – Sum Of All Chemical Reactions Metabolic Reactions – Anabolic/ Catabolic Reactions Characteristics of Anabolic Reactions – Endergonic Reactions, Small to Complex. (<) Characteristics of Catabolic Reactions – Exergonic Reactions, Complex to Small. (>) Basis of These Reactions - Redox Reactions Reduction - loss of oxygen, gain of electrons, gains hydrogen, gains less electronegative atom O xidation - loss of Hydrogen, l o ss of electrons, gains o xygen, gains more electronegative atom. (OOO) CTECK SBS


Enzymes Enzymes bring about the metabolic reactions. Enzymes in Redox Reaction – Cofactor – To shuttle the electrons. 2 Redox Cofactors – NAD, FAD Once the Catabolism is over – Energy has to be supplied for anabolism to take place.. Right? Which serves the Energy? Why? CTECK SBS

ATP Generation:

ATP Generation CTECK SBS


Glycolysis Start Material → Glucose Catabolic Process, Anaerobic/Aerobic Process 2 important stages → Preparatory stage, Energy Conserving stage. Generates - 2 ATP, 2 pyruvic acid, 1 NADH Key Enzymes – Hexokinase, Phospho-Fructokinase, Pyruvate kinase Alternates to Glycolysis Hexose monophosphate pathway Entner-Doudoroff pathway in Pseudomonas Phosphoketolase pathway CTECK SBS

PowerPoint Presentation:

ADP Glucose Glucose 6-phosphate Fructose 1,6-diphosphate Glyceraldehyde 3-phosphate Dihydroxyacetone phosphate Fructose 6-phosphate ATP P ADP ATP P P Glycolysis: preparatory stage 2 ATPs are used Glucose is split to form 2 molecules of Glyceraldehyde-3-phosphate P P P Hexokinase Phosphoglucoisomerase Phosphofructokinase aldolase Triose phosphate isomerase CTECK SBS

PowerPoint Presentation:

ADP Glyceraldehyde 3-phosphate Diphosphoglyceric acid ATP Glycolysis: energy conserving stage For each initial glucose molecule; 2 Glyceraldehyde-3-phosphate oxidized to 2 Pyruvic acid 4 ATP produced 2 NADH produced NAD + NAD + NADH NADH P P P P P P P P P P 3-phosphoglyceric acid ADP ATP 2-phosphoglyceric acid P P P P H 2 O H 2 O Phosphoenolpyruvic acid ADP ATP Pyruvic acid ADP ATP Triose phosphate dehydrogenase Phosphoglycerokinase Phosphoglyceromutase Enolase Pyruvate kinase CTECK SBS

Entner-Doudoroff pathway:

Entner-Doudoroff pathway Found in Pseudomonas Lacks 6-Phospho Fructokinase So, Glucose-6-Phosphate → 6-phosphogluconate → 2 keto 3 Deoxy 6 phospho gluconate → Glyceraldehyde 3 Phosphate Produces 2 Pyruvate, 1 NADPH, 1 NADH, 1 ATP Less efficient than EMP pathway. CTECK SBS

Hexose monophosphate pathway:

Hexose monophosphate pathway Found in Acetobacter and Gluconobacter Is an Amphibolic Pathway - ? Lacks 6-Phospho Fructokinase So, Glucose-6-Phosphate → 6-phosphogluconate → Ribulose 5 Phosphate Produces 2 Pyruvate, 2 NADPH, 2 NADH, 2 ATP or Ribulose 5 Phosphate, CO2, 2 NADPH or called as phospho Ketolase Pathway 12 NADPH, CO2 → Complete Oxidation of Glucose Less efficient than EMP pathway. Takes place in Heterolactic Bacteria and in RBC higher organisms CTECK SBS

Revision Test 1:

Revision Test 1 Anaerobic metabolism refers to the generation of ATP: (a) without the involvement of ADP (b) without the use of glycogen (c) without the use of oxygen (d) in the absence of available oxygen (e) by the conversion of pyruvate to lactate Glycolysis is the name given to the pathway involving the conversion of: (a) glycogen to glucose-6-phosphate (b) glycogen or glucose to fructose (c) glycogen or glucose to pyruvate or lactate (d) glycogen or glucose to pyruvate or acetyl CoA (e) glucose or fatty acids to pyruvate or acetyl CoA CTECK SBS


Respiration CTECK SBS

After Glycolysis:

After Glycolysis After glucose is broken down to pyruvic acid, pyruvic acid can be channeled into either Aerobic Respiration OR Fermentation Aerobic respiration Uses the TCA cycle and electron transport chain Final electron acceptor is O 2 Anaerobic respiration Uses the TCA cycle and only PART of the electron transport chain Final electron acceptor is an inorganic molecule other than O 2 , like nitrate or sulfate. CTECK SBS

PowerPoint Presentation:

ADP FADH 2 FAD NADH NAD + NADH NAD + NAD + NAD + Pyruvate CoA CoA CoA CoA H 2 O CO 2 CO 2 a -ketoglutarate Succinate Fumarate Malate Oxaloacetate Isocitrate NADH NADH CO 2 Citrate Acetyl-CoA CoA ATP P Succinyl-CoA CoA TCA cycle For every molecule of glucose (2 acetyl CoA) the TCA cycle generates 4 CO 2 6 NADH 2 FADH 2 2 ATP Location - Cytoplasm CTECK SBS

Next - ETC:

Next - ETC Location - Plasma Membrane ETC – Flavoproteins, Cytochromes, Coenzyme Q Terminal Acceptor – O2 Creates ATP by Chemiosmosis 38 ATP produced. CTECK SBS

Revision Test 2:

Revision Test 2 Substrate-level phosphorylation differs from oxidative phosphorylation in that: (a) substrate-level phosphorylation involves the transfer of electrons (b) substrate-level phosphorylation only occurs in the cytosol (c) oxidative phosphorylation only occurs in the cytosol (d) oxidative phosphorylation involves the transfer of electrons (e) GTP is always involved in substrate-level phosphorylation How many ATP molecules can be derived from each molecule of acetyl CoA that enters the Krebs’ Cycle? (a) 6 (b) 12 (c) 18 (d) 38 (e) 39 CTECK SBS

Anaerobic Respirations:

Anaerobic Respirations Uses Glycolysis, TCA cycle and ETC. Final Electron Acceptors are inorganic molecules like Some bacteria use NO 3 - and produce either NO 2 - , N 2 O or N 2 ( Pseudomonas and Bacillus ) Desulfovibrio use SO 4 2- to form H 2 S Methanogens use carbonate to form methane The amount of ATP generated varies with the pathway Only part of the TCA cycle operates under anaerobic conditions Not all ETC carriers participate in anaerobic respiration ATP yield never as high as aerobic respiration CTECK SBS


Fermentation CTECK SBS

Types of fermentation:

Types of fermentation Acid Fermentation Homolactic Only lactic acid Streptococcus and Lactobacillus Heterolactic Mixture of lactic acid, acetic acid and CO 2 Can result in food spoilage Can produce Yogurt Sauerkraut Pickles CTECK SBS

End products of fermentation:

End products of fermentation CTECK SBS

Amphibolic view of metabolism:

Amphibolic view of metabolism CTECK SBS

Revision Test 3:

Revision Test 3 Which is not an end product of cellular respiration? CO2 Water O2 ATP Mixed acids produced by E.coli are Formic Acid, Lactic acid, acetic acid Formic acid, propionic acid, acetic acid Formic acid, lactic acid, propionic acid CTECK SBS


Photosynthesis Photo: Conversion of light energy into chemical energy (ATP) Light-dependent (light) reactions Synthesis: Fixing carbon into organic molecules Light-independent (dark) reaction, Calvin-Benson cycle Oxygenic: 6 CO2 + 12 H2O + Light energy C6H12O6 + 6 O2 + 6 H2O Anoxygenic: CO2 + 2 H2S + Light energy [CH2O] + 2 A + H2O CTECK SBS

PowerPoint Presentation:

What is the order of transport of electrons? Does it produce the reducing power? CTECK SBS

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Nitrogen Fixation:

Nitrogen Fixation Nitrogen fixation is limited to prokaryotes. Some eubacteria and a few archebacteria can fix nitrogen - but no eukaryotic cells can do this. Some N-fixing bacteria are free-living whereas other form symbiotic associations with plants. It is a anaerobic reaction. Takes place in heterocysts. Nitrogenase enzyme has 2 complexes Iron Complex and Molybdenum Iron Complex CTECK SBS

PowerPoint Presentation:

N2 + 8H+ + 8e- + 16 ATP → 2NH3 + H2 + 16ADP + 16 Pi Examples of nitrogen-fixing bacteria Free living – Aerobic – Eg: Azotobacter, Beijerinckia, Klebsiella (some), Cyanobacteria (some)* Anaerobic - Clostridium (some), Desulfovibrio, Purple sulphur bacteria*, Purple non-sulphur bacteria*, Green sulphur bacteria* Symbiotic Bacteria – Legumes – Eg: Rhizobium CTECK SBS

PowerPoint Presentation:


Revision Test 4:

Revision Test 4 How many molecules of G3P are used to reproduce Ribulose 5 Phosphate? 5 4 3 2 Which of the following is not the End products of photosynthesis… 1G3P, 9ATP, 6NADPH 4GTP, 6ATP, 9NADPH 1 Glucose, 18ATP, 12NADPH CTECK SBS

PowerPoint Presentation:

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