Chapter 12 (part 1)

Citric Acid Cycle

Gylcolysis

TCA Cycle

Electron Transport andOxidative phosphorylation

Entry into the TCA Cycle

Pyruvate Dehydrogenase

Citrate Synthase• Only step in TCA cycle that involves the

formation of a C-C bond

Aconitase

Isocitrate Dehydrogenase

-Ketoglutarate Dehydrogenase

Succinyl-CoA Synthetase

Fumarase

Malate Dehydrogenase

Reduced Coenzymes Fuel ATP Production

• Acetyl-CoA + 3 NAD+ + Q + GDP + Pi +2 H20 HS-CoA + 3NADH + QH2 + GTP + 2 CO2 + 2 H+

• Isocitrate Dehydrogenase 1 NADH=2.5 ATP• -ketoglutarate dehydrogenase 1 NADH=2.5

ATP• Succinyl-CoA synthetase 1 GTP=1 ATP• Sunccinate dehydrogenase 1 QH2=1.5 ATP• Malate Dehydrogenase 1 NADH=2.5 ATP

• Total of 10 ATPs gained from oxidation of 1 Acetyl-CoA

Regulation of TCA

Cycle

Protein/amino acid

Catabolites feedInto the TCA

Cycle

Fats breakdown and feed

into the TCA Cycle

TCA Cycle provides intermediates for many biosynthetic processes

The Anaplerotic ReactionsThe "filling up" reactions

• PEP carboxylase - converts PEP to oxaloacetate

• Pyruvate carboxylase - converts pyruvate to oxaloacetate

• Malic enzyme converts pyruvate into malate

Following the carbons through

the TCA cycle