Lecture #19: Glycolysis: Overview and Reactions

1. Know that glycolysis occurs in the cytosol and is a sequence of 10 enzyme catalyzed reactions by which one molecule of glucose is converted to two molecules of pyruvate, with the net production of 2 ATP and the reduction of 2 NAD⁺ to 2 NADH. See animated glycolytic pathway.
2. Stage I: Know that the energy investment stage of glycolysis (reactions 1-5) consumes 2 ATP (starting from glucose). Know the reactions where ATP is consumed.
3. Stage II: Know that the energy recovery stage of glycolysis (reactions 6-10) produce 4 ATP per glucose (for a net yield of 2 ATP per glucose molecule). Know the reactions where ATP is produced (substrate level phosphorylation).
4. For all 10 reactions, know names of reactants and products; identity of functional groups lost or added; and name and classification of enzymes that catalyze reactions. (Go to http://www.expasy.ch/enzyme/ to find classification of enzyme).
5. Identify one redox reaction and note what is oxidized and what is reduced. Explain coupling between reactions catalyzed by glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and phosphoglycerate kinase (PKG) (pg. 396).
6. Irreversible reactions: Know the 3 "far from equilibrium" reactions in glycolysis and the enzymes that catalyze these reactions (hexokinase, phosphofructokinase, pyruvate kinase).
7. Know the 2 potential fates of NADH (regenerated by reduction of NAD⁺ under anaerobic conditions; carrier of electrons to electron transport chain under aerobic conditions).
8. Know the three fates of pyruvate (lactate, ethanol [in yeast], citric acid cycle).
9. Know that erythrocytes (red blood cells) synthesize and degrade 2,3 BPG by a detour from the glycolytic pathway (Box 14-1; pg. 398).