Topic 29: Pyruvate Oxidation

Pyruvate Oxidation

Pyruvate is converted to acetyl-CoA, producing reduced electron carriers and CO2.

Mitochondria

• Glycolysis occurs in the cytosol

• All other processes of cellular respiration occur in Mitochondria, including Pyruvate Oxidation

Pyruvate Oxidation (Acetyl-CoA synthesis) Oxidation

How many molecules of Acetyl-CoA per Pyruvate? 1

How many molecules of CO2? 1

How many molecules of NADH? 1

2 pyruvate —> 2 acetyl-CoA

Substrate-Level Phosphorylation: 0 ATP

Oxidative Phosphorylation: 2 NADH = 5 ATP

Total ATP: 5 ATP

General Review

• Describe pyruvate oxidation as the oxidation of pyruvate to acetyl-CoA, which is the starting material for the citric acid cycle.

• Identify the products of pyruvate oxidation within the context of cellular respiration.

• Describe the cellular location of pyruvate oxidation with reference to the locations of the other phases of cellular respiration.

How many carbon atoms does pyruvate contain? 

Where is pyruvate located when it is first produced during glycolysis? 

Where is pyruvate oxidized? 

• Three

• Cytosol/cytoplasm

• Mitochondrial matrix

How many ATP are generated by pyruvate oxidation? 

How many electron carriers and which ones are generated by pyruvate oxidation?

0 ATP generated directly 

NOTE: could also say that 5 are generated from 2 NADH per glucose, or 2.5 generated from 1 NADH per pyruvate.

1 NADH per pyruvate 

OR 

2 NADH per glucose

(only need to state one)

At the end of pyruvate oxidation, but before the subsequent stages in cellular respiration, which molecules contain some of the chemical energy held in the original pyruvate molecule?

Acetyl CoA

NADH

Which molecule enters pyruvate oxidation from glycolysis? How many carbons does it have?

Which molecule leaves pyruvate oxidation to enter the citric acid cycle? How many carbons does it have?

Pyruvate - 3 carbons

Acetyl Co-A - 2 carbons

Where in the cell is pyruvate generated? Where in the cell is it oxidized?

It is generated in the cytosol/cytoplasm. It is oxidized in the matrix of the mitochondria.

What are the products that are formed during pyruvate oxidation? How many of each are produced per pyruvate. Consider the molecules that carry the carbons found in the original pyruvate molecule as well as any molecule that carries energy originally contained in the pyruvate molecule.

1 acetyl coA

1 CO2

1 NADH