Oxidation of Pyruvate
- Pyruvate (from glycolysis) is transported from the cytosol into the mitochondria
- If oxygen is available, aerobic respiration will continue
- Movement of pyruvate across the double membrane of the mitochondria occurs by active transport
- It requires a transport protein and a small amount of ATP
Entry of Pyruvate into the Mitochondrion Diagram
Pyruvate enters the mitochondrial matrix from the cytosol (cytoplasm) by active transport
- This stage links glycolysis to the Krebs cycle
- Pyruvate is oxidized and acetyl coenzyme A (acetyl CoA) is formed
- During the process,
- Hydrogen and an electron removed from pyruvate (dehydrogenation) are used to reduce NAD+ to form NADH
- Carbon dioxide is removed from pyruvate (decarboxylation)
- CoenzymeA (CoA) is added to form acetyl CoA
- The products are then used as follows:
- Acetyl CoA - is used in the Krebs cycle
- Carbon dioxide (CO2) - which is released as a waste product
- NADH - provides electrons to drive the electron transport chain
Oxidation of Pyruvate Diagram
The first stage of pyruvate oxidation occurs in the mitochondrial matrix.
It dehydrogenates and decarboxylates the three-carbon pyruvate to produce the two-carbon acetyl CoA that can enter the Krebs Cycle.
Exam Tip
Remember that there are two pyruvate molecules produced per glucose molecule so you need to multiply everything by 2 when thinking about what happens to a single glucose molecule in aerobic respiration.
