TCA Cycle

Cellular Metabolism - CH 17 and 18
Cell Metabolism

Converts the product from glycolysis and pyruvate decarboxylation and produces a product to be used in the electron transport chain

Tricarboxylic Acid Cycle/Krebs Cycle/Citric Acid Cycle

? kJ

Function/Purpose:

• Takes Acetyl CoA and forms a six carbon "fuel" for the TCA cycle
• This fuel is "combusted" to form NADH

Fundamentals:

• Substrate level phosphorylation

LOC:

• Mitochondria - mitochondrial matrix

Summary:

• A 2C and 4C molecule is converted into a 6C molecule
• Preparation for combustion through conversion of 6C molecule
• "Combustion" step 1 - reductes to C5
• "Combustion" step 2 - reductes to C4
• First step to regenerate original 4C molecule
  • Is like a stop light to give a buffer because there is another process utilizes the reverse
• Second step to regenerate original 4C molecule
• Original 4C molecule is regenerated and cycle starts again

Detailed Steps:

• Acetyl CoA and Oxaloacetate into Citrate
  • Citrate Synthase
• Citrate into D-isocitrate
  • Aconitase
• D-isocitrate into alpha-ketoglutarate
  • Isocitrate Dehydrogenase
• alpha-ketoglutarate into Succinyl CoA
  • alpha-ketoglutarate Dehydrogenase
• Succinyl CoA into Succinate
  • Succinyl CoA Synthetase
• Succinate into Fumarate
  • Succinate Dehydrogenase - ETC C2 enzyme!
• Fumarate into L-malate
  • Fumarase
• L-malate into Oxoaloacetate
  • Malate Dehydrogenase

Concepts:

• Combustion
• Enzymes
• Pyruvate Decarboxylation
• Phosphorylation

Additional Information:

• Wikipedia