Citric Acid Cycle

Question 1

What happens to pyruvate under aerobic conditions?

Answer 1

It is transported from the cytosol into the mitochondrial matrix.

Question 2

pyruvate dehydrogenase complex has a complex of what 3 enzymes.

Answer 2

pyruvate dehydrogenase (E1), dihydrolipoyl transacetylase (E2), dihydrolipoyl dehydrogenase (E3)

Question 3

the citric acid cycle is the final common pathway for the oxidation of what fuel molecules?

Answer 3

Carbs, fats and proteins.

Question 4

Carbohydrates, fatty acids and some amino acids enter the cycle as what?

Answer 4

Acetyl coenzyme A

Question 5

Citric acid cycle is also known as…

Answer 5

Krebs cycle, citrate cycle, tricarboxylic acid (TCA) cycle.

Question 6

In the Citric acid cycle, what is an activated acetyl (c2) unit oxidised to?

Answer 6

CO2 and H2O

Question 7

Where does it take place?

Answer 7

in the mitochondrial matrix in eukaryotes.

Question 8

Reaction 1 name of citric acid cycle and explain it.

Answer 8

Citrate synthase. Condensation of Acetyl co-A with oxaloacetate forms a c4 molecule citrate. Reaction is catalysed by the allosteric enzyme, citrate synthase.

Question 9

Reaction 2 name of citric acid cycle and explain.

Answer 9

Aconitase. citrate is isomerised. citrate—cis aconitate—isocitrate

Question 10

Reaction 3 name and explain.

Answer 10

.socitrate dehydrogenase (allosteric enzyme) inhibited by NADH & ATP and activated by NAD+ and ADP. Isocitrate is oxidised. loss of NAD+