The Link Reaction (Mitochondrial Matrix)
- Pyruvate dehydrogenase removes hygrogen atoms from pyruvate. It is dehydrogenated.
- Pyruvate decarboxylase removes a carboxyl group (which becomes carbon dioxide) from pyruvate. It is decarboxylated.
- NAD accepts the hydrogen atoms.(becomes reduced NAD)
- Coenzyme A accepts acetate to become acetyl coenzyme A.
CoA carries acetate to the Krebs Cycle.
No ATP is produced
reduced NAD takes hydrogen atoms to inner mitochondrial membrane for oxidative phosphorylation.
The Krebs Cycle (Mitochondrial Matrix)
- Acetate is offloaded from CoA and joins oxaloacetate (4C) to form citrate (6C)
- Citrate is decarboxylated and dehydrogenated to form a 5C compound. The hydrogen atoms are accepted by NAD.
- The 5C compound is decarboxylated and dehdrogenated to form a 4C compound and another molecule of reduced NAD.
- The 4C compound is changed to another 4C compound. ADP is phosphorylated to produce ATP (substrate level phosphorylation)
- The second 4C compound is changed to another 4C compound. A pair of hydrogen atoms are removed by FAD.
- The third 4C compound is further dehydrogenated and regenerates oxaloacetate. Another molecule of NAD is reduced.
2 turns of the cycle = one molecule of glucose.
Products: 6 reduced NAD, 2 reduced FAD, 4 CO2, 2 ATP (for one glucose)