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TCA cycle citric acid cycle krebs cycle.
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- 2. Respiration Conversion of nutrientsinto useful energy for the cell Carbohydrates - Sugars Proteins - Amino Acids Fats - Fatty Acids & Glycerol
- 3. Citric Acid Cycle(CAC) “Kreb Cycle” Tricarboxylic Acid Cycle 2/3 of O2 consumption needed for oxidation of Acetyl CoA CO2 • Occurs exclusively in the mitochondrion (matrix) • OAA acts as carrier or acceptor of acetyl CoA units – is regenerated • “Burns” acetyl CoA to CO2 – during this oxidation eˉs from acetyl CoA are trapped in the form of: NADH FADH Pyruvate Pyruvate Dehydrogenase Complex “links” glycolysis to CAC + 2eˉ + 2eˉ GTP ATP (substrate level phosphorylation) + 2eˉ + 2eˉ
- 4. The Krebs Cycle CitricAcid Cycle; The TCA Cycle Pyruvate (actually the acetyl group) from glycolysis is degraded to CO2 The acetyl group is formed in stage II of metabolism from carbohydrate and amino acid metabolism 1GTP (ATP in bacteria) and 1 FADH2 is produced during one turn of the cycle 3 NADH are produced during one turn of the cycle NADH and FADH2 energize electron transport and oxidative phosphorylation Eight reactions make up the Krebs cycle
- 6. Multimolecular aggregate 3 Enzymes 5Coenzymes 5 Reactions CoA contains the vitamin Pantothenic acid Product Inhibition Coenzymes Thiamine Pyrophosphate (TTP) NAD+ FAD+ CoA Lipoic acid Mitochondrial matrix Cytoplasm Pyruvate *Pyruvate transporter Irreversible
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- 8. Pyruvate TPP-Acetaldehyde Acetyl-Lipoamide Acetyl-CoA E1 E2 E3 CO2 Electron transfer to lipoamide-S-S Pyruvate Dehydrogenase FAD FADH2 NAD+ NADH Acetaldehyde Bacteria/ Yeast (Mostly in low O2) Pyruvate decarboxylase Dihydrolipoyl transacetylase Dihydrolipoyl dehydrogenase
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- 10. √ Allosteric Regulation √Allosteric Regulation cAMP dependent Skeletal muscle Contraction
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- 15. + NAD+ + NADH+ CO2 Isocitrate Dehydrogenase First oxidative decarboxylation
- 16. + NAD+ + CoASH +NADH + CO2 α-ketoglutarate dehydrogenase Second oxidative decarboxylation
- 17. + GDP +Pi + GTP + CoASH Succinyl-CoA Synthetase Symmetrical Product Only Substrate Level Phosphorylation in Cycle
- 18. + FAD + FADH2 Succinate Dehydrogenase ThirdOxidation of Cycle
- 19. Succinate Dehydrogenase Enzyme isembedded in inner mitochondrial membrane Only enzyme of Citric Acid Cycle not found in matrix
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- 21. + NAD+ + NADH Malate Dehydrogenase Fourthand final oxidation of cycle
- 23. Citric Acid CycleSummary Input 2 Carbons (1 Acetyl CoA) Release 2 CO2 Molecules Four Oxidations 3 NADH, 1 FADH2, 1 GTP Per Turn of Cycle
- 27. Each Citric AcidCycle Intermediate Functions in Other Pathways Citrate - Glyoxylate Cycle, Allosteric Effector, Shuttle System Isocitrate - Glyoxylate Cycle a-Ketoglutarate - Amino Acid/Nitrogen Metabolism Succinyl-CoA - Heme Synthesis, Amino Acid Metabolism Succinate - Glyoxylate Metabolism, Odd Chain Fatty Acid Metabolism Fumarate - Nucleotide Metabolism Malate - Shuttle System Oxaloacetate - Gluconeogenesis, Amino Acid Metabolism
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