4.4: Pyruvate Oxidation (Acetyl CoA synthesis) and the Citric Acid Cycle

Question 1

Where does pyruvate oxidation occur?

Answer 1

Pyruvate oxidation is the first step that takes place inside the mitochondria (for eukaryotes, cytoplasm for pro)

Question 2

What are the inputs of pyruvate oxidation? The outputs?

Answer 2

One pyruvate molecule (input) oxidizes into one molecule of CO2 (output) and one molecule of NADH (output) to synthesize into one molecule of acetyl-CoA.

Question 3

How many molecules of acetyl-CoA are produced from a single glucose molecule?

Answer 3

Glucose -> 2 pyruvate -> 2 acetyl CoA

Question 4

What happens during the citric acid cycle?

Answer 4

Fuel molecules are completely oxidized, leading to a production of much more ATP than is obtained by glycolysis alone.

Question 5

Where does the citric acid cycle occur?

Answer 5

Same as acetyl-CoA synthesis, mitochondria.

Question 6

What are the inputs of the citric acid cycle? The outputs?

Answer 6

One acetyl-CoA group (input) forms a 6-carbon citric acid molecule with oxaloacetate (input). This is oxidized in a series of reactions to regenerate the 4C molecule (output) and produces two CO2 (output) molecules, 3 NADH (output) e- carrier, and 1 FADH2 e- carrier.

Question 7

How many molecules of ATP are produced from a single glucose molecule?

Answer 7

Glucose -> 2 acetyl CoA -> 2 ATP, 3 NADH, 2FADH2/ per cycle