Glycolysis - Glycolysis Bryant Miles O CH H C OH HO C H H C...

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Glycolysis Bryant Miles O OH OH OH OH CH 2 OH O CH CO H H CH HO H H H H H 2 H O OH OH OH OH CH 2 OH α - D -glucose β - D -glucose D -glucose D -Glucose is a major fuel for most organisms. D -Glucose metabolism occupies the center position for all metabolic pathways. Glucose contains a great deal of potential energy. The complete oxidation of glucose yields 2,840 kJ/mol of energy. Glucose + 6O 2 6CO 2 + 6H 2 O Δ G o ’ = 2,840 kJ/mol Glucose also provides metabolic intermediates for biosynthetic reactions. Bacteria can use the skeletal carbon atoms obtained from glucose to synthesize every amino acid, nucleotide, cofactor and fatty acid required for life. For higher plants and animals there are three major metabolic fates for glucose. Nearly every living cell catabolizes glucose and other simple sugars by a process called glycolysis. Glycolysis differs from one species to another only in the details of regulation and the fate of pyruvate. Glycolysis is the metabolic pathway that catabolizes glucose into two molecules of pyruvate. O H OH H OH H OH H OH CH 2 OH H H 3 CC O C O O - 2 Glycolysis occurs in the cytosol of cells and is essentially an anaerobic process since the pathway’s principle steps do not require oxygen. The glycolytic pathway is use to be referred to as the Embfen- Meyerhof pathway in honor of the two of the three biochemical pioneers (What about Jacob Parnas?) who discovered it. The glycolytic pathway is shown below.
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Glucose Glucose 6-phosphate Fructose 6-phosphate Fructose 1,6-bisphosphate Dihydroxyacetone phosphate Glyceraldehyde 3-phosphate + 1,3-Bisphosphoglycerate 3-Phosphoglycerate 2-Phosphoglycerate Phosphoenolpyruvate Pyruvate Glyceraldehyde 3-phosphate ATP ADP ADP Hexokinase Phosphoglucosiomerase Phosphofructokinase I Aldolase Triose phosphate isomerase ADP ADP NAD + +Pi NADH + H + Glyceraldehyde 3-phosphate Dehydrogenase Phosphoglycerate Kinase Phosphoglycerate Mutase Enolase Pyruvate Kinase 1,3-Bisphosphoglycerate 3-Phosphoglycerate 2-Phosphoglycerate Phosphoenolpyruvate Pyruvate ADP ADP + Glyceraldehyde 3-phosphate Dehydrogenase Phosphoglycerate Kinase Phosphoglycerate Mutase Enolase Pyruvate Kinase Phase I Preparatory Phase First Priming reaction Second Priming reaction NADH + H + Phase II Payoff Phase H 2 O H 2 O Net Reaction: Glucose + 2ADP + 2 Pi 2 Pyruvates + 2 ATP + 2 NADH + 4H + +2H 2 O
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Glycolysis consists of 10 enzyme catalyzed reactions. The pathway can be broken down into two phases. The first phase encompasses the first five reactions to the point that glucose is broken down into 2 molecules of glyceraldehyde 3-phosphate. Phase 1 consumes two molecules of ATP. The second phase includes the last five reactions converting glyceraldehyde 3-phosphate into pyruvate. Phase 2 produces 4 molecules of ATP and 2 molecules of NADH. The net reaction (Phase 1 + Phase 2) produces 2 molecules of ATP and 2 molecules of NADH per molecule of glucose.
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Glycolysis - Glycolysis Bryant Miles O CH H C OH HO C H H C...

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