Prep for CAC

Question 1

The irreversible conversion of pyruvate into

Answer 1

Acetyl CoA is the linked between glycolysis and the citric acid cycle

Question 2

Conversion of pyruvate into Acetyl-CoA requires:

Answer 2

1) enzymes of the pyruvate dehydrogenase complex: pyruvate dehydrogenase, dihydrolipoyl transacetylase, and dihydrolipoyl dehydrogenase
2) coenzymes: TPP, lipoic acid, FAD, CoA, and NAD+

Question 3

Steps of the coupled reaction of pyruvate to acetyl CoA

Answer 3

1) Decarboxylation (removal of CO2, pyruvate dehydrogenase)
2) Oxidation (removal of 2e-, pyruvate dehydrogenase)
3) Transfer to CoA (dihydrolipoyl transacetylase)
4) Oxidized form of lipoamide is regenerated (dihydrolipoyl dehydrogenase, FADH2 + NAD+ -> FAD + NADH + H+)

Question 4

Acetyl CoA is a precursor to:

Answer 4

1) Citric Acid Cycle (Oxidized + ATP)

2) Fatty acid synthesis

Question 5

Regulation of the Pyruvate Dehydrogenase Complex

Answer 5

Inhibited by: Acetyl CoA, NADH, and ATP

Activated by: ADP and pyruvate