Cellular Respiration Part 1 Harvesting Chemical Energy from Glucose

Releasing Energy From Glucose Glucose (6C) 2 X Pyruvate (3C) 2 X Acetyl-CoA (2C) Cytoplasm Mitochondrion Citric Acid Cycle ATP e - Carriers Electron Transport Chain ½ O 2 H2OH2OH2OH2OATP 2 H + 4 CO 2 2 CO 2 2 CO 2 ATP Glycolysis Energy Released e-e-e-e- e-e-e-e- e-e-e-e- O 2 present

Redox Reactions Reduction: Gain of one or more electrons or hydrogen atomsReduction: Gain of one or more electrons or hydrogen atoms Oxidation: Loss of one or more electrons or hydrogen atomsOxidation: Loss of one or more electrons or hydrogen atoms Electron carrier NAD+ accepts two electrons and one proton to become NADH

Energy Yield of Glucose Oxidation C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O + energyC 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O + energy –40% of released energy captured in ATP Involves two electron carriersInvolves two electron carriers –NAD + + 2H electrons  NADH + H + –FAD + 2H electrons  FADH 2 –Electrons donated to Electron Transport Chain to produce ATP

Overview of Glycolysis 4 ATP 4 ATP 2 NADH 2 NADH 2 ATP 2 ATP 2 NAD + 2 NAD + Set of 10 reactions 2 X Pyruvate (3C) CCCCCC Glucose (6C) CCCCCC Net gain of 2 ATP Occurs in cytoplasm under anaerobic conditions Gluconeogenesis can convert pyruvate  glucose

Energy Investment Reactions of Glycolysis Step 1 Reaction Type Phosphorylation Reactants Glucose ATP Enzyme Hexokinase Products Glucose 6-phosphate ADP Energy Carriers - 1 ATP

Energy Investment Reactions of Glycolysis Step 2 Reaction Type Isomerization Reactant Glucose 6-phosphate Enzyme Phosphoglucoisomerase Product Fructose 6-phosphate

Energy Investment Reactions of Glycolysis Step 3 Reaction Type Phosphorylation Reactant Fructose 6-phosphate ATP Enzyme Phosphofructokinase Product Fructose-1,6-bisphosphate ADP Energy Carriers -1 ATP

Energy Investment Reactions of Glycolysis--Step 4 Reaction Type Cleavage ReactantFructose-1,6-bisphosphate EnzymeAldolase Products Dihydroxyacetone phosphate Glyceraldehyde 3-phosphate

Energy Investment Reactions of Glycolysis Step 5 Reaction Type Isomerization Reactant Dihydroxyacetone Phosphate EnzymeIsomerase Product Glyceraldehyde 3-phosphate

Energy-Harvesting Reactions of Glycolysis Step 6 Reaction Type Redox + Phosphorylation Reactants 2 X Glyceraldehyde 3-Phosphate 2 NAD +, 2 P i Enzyme Triose phosphate dehydrogenase Products 2 X 1,3-Bisphosphoglycerate Energy Carriers 2 NADH + 2 H +

Energy-Harvesting Reactions of Glycolysis Step 7 Reaction Type Phosphorylation Reactants 2 X 1,3-Bisphosphoglycerate 2 ADP Enzyme Phosphoglycerokinase Products 2 X 3-Phosphoglycerate Energy Carriers +2 ATP Substrate Level Phosphorylation

Energy-Harvesting Reactions of Glycolysis Step 8 Reaction Type Isomerization Reactants 2 X 3-Phosphoglycerate Enzyme Phosphoglyceromutase Products 2 X 2-Phosphoglycerate

Energy-Harvesting Reactions of Glycolysis Step 9 Reaction Type Dehydration Reactants 2 X 2-Phosphoglycerate 2 X 2-Phosphoglycerate EnzymeEnolase Products 2 Phosphoenolpyruvate 2 H 2 O

Energy-Harvesting Reactions of Glycolysis Step 10 Reaction Type Phosphorylation Reactants 2 Phosphoenolpyruvate 2 ADP Enzyme Pyruvate kinase Products 2 Pyruvate Energy Carriers +2 ATP Substrate Level Phosphorylation

Pyruvate Oxidation Reaction Type Redox Reactants 2 Pyruvate 2 Coenzyme A (CoA) 2 NAD + EnzymeDehydrogenase Products 2 Acetyl CoA 2 CO 2 Energy Carriers 2 NADH + 2H + 2 X Occurs in the Mitochondrial Matrix Not Reversible, Cannot convert 2C  3C for pyruvate  glucose pathway

Overview of the Citric Acid Cycle CoA CC Acetyl-CoA (2C) 2 X Citric Acid Cycle Set of 8 reactions 6 NAD + 6 NAD + 6 NADH 6 NADH 2 FAD 2 FAD 2 FADH 2 2 FADH 2 2 ADP 2 ADP 2 ATP 2 ATP Electron Transport Chain 4 CO 2 4 CO 2C

Citric Acid Cycle Step 1 Reaction Type Synthesis Reactants 2 Acetyl-CoA 2 Oxaloacetate Enzyme Citrate synthase Products 2 Citrate

Citric Acid Cycle Step 2 Reaction Type Isomerization Reactants 2 Citrate EnzymeAconitase Products 2 Isocitrate

Citric Acid Cycle Step 3 Reaction Type Redox + Decarboxylation Reactants 2 Isocitrate, 2 NAD + EnzymeDehydrogenase Products 2 Alpha-Ketoglutarate 2 CO 2 Energy Carriers 2 NADH + 2H +

Citric Acid Cycle Step 4 Reaction Type Redox + Decarboxylation Reactants 2 Alpha-Ketoglutarate, 2 CoA 2 NAD + EnzymeDehydrogenase Products 2 Succinyl-CoA, 2 CO 2 Energy Carriers 2 NADH + 2 H +

Citric Acid Cycle Step 5 Reaction Type Redox + Phosphorylation Reactant 2 Succinyl-CoA, 2 ADP EnzymeSynthase Products 2 Succinate, 2 CoA Energy Carriers 2 ATP, Substrate Level Phosphorylation

Citric Acid Cycle Step 6 Reaction Type Redox Reactant 2 Succinate EnzymeDehydrogenase Products 2 Fumarate Energy Carriers 2 FADH 2

Citric Acid Cycle Step 7 Reaction Type Hydration Reactants 2 Fumarate, 2 H 2 O EnzymeFumarase Products 2 Malate

Citric Acid Cycle Step 8 Reaction Type Redox Reactants 2 Malate, 2 NAD + EnzymeDehydrogenase Products 2 Oxaloacetate Energy Carriers 2 NADH + 2 H +

Free Energy Change for Glucose Oxidation

Energy Harvested from Glucose (Cytoplasm) Glucose 2 NADH 6 NADH 2 FADH 2 2 Pyruvates 2 CO 2 4 CO 2 2 ATP 4 ATP (Mitochondrial Matrix) (Inner Membrane) 2 ATP 32 ATP Electron Transport System Glycolysis Citric Acid Cycle Water Oxygen 2 ATP Net Gain