The Fate of Pyruvate

Question 1

Name the 3 Fates of Pyruvate

Answer 1

Ethanolic Fermentation, Lactate Production & The Pyruvate Dehydrogenase Complex (Link Reaction)

Question 2

What is the purpose of Ethanolic fermentation and Lactate production?

Answer 2

To regenerate NAD+ to allow glycolysis to continue

Question 3

Describe the pathway of Ethanolic Fermentation of Pyruvate

Answer 3

Pyruvate Decarboxylase converts it into ethanal, which is then converted to ethanol by ethanol dehydrogenase, which produces NAD+

Question 4

Describe the reaction in lactate production

Answer 4

Lactate Dehydrogenase converts pyruvate into lactate converting NADH into NAD+

Question 5

Which reactions might occur in humans and in which conditions?

Answer 5

In aerobic conditions, the Pyruvate dehydrogenase complex is the most common pathway.
In anaerobic conditions, lactate production occurs so ATP can continue to be generated by glycolysis.

Question 6

Name the 3 enzymes in the Pyruvate dehydrogenase complex

Answer 6

E1: Pyruvate Decarboxylase
E2: Lipoamide reductase transacetylase
E3: Dihydrolipoyl dehydrogenase

Question 7

Name the Cofactors involved in the Pyruvate dehydrogenase complex, and which enzyme they may be attached to

Answer 7

Thiamine pyrophosphate ((TPP)) (Pyruvate decarboxylase)
Lipoamide (Lipoamide reductase-transacetylase)
FAD (Dihydrolipoyl dehydrogenase)
NAD+
CoA

Question 8

Describe the pathway of the Pyruvate dehydrogenase complex

Answer 8

1. Decarboxylation of Pyruvate by E1 to give Hydroxyethyl TPP (2C)
2. Transferred to lipoamide and oxidised to actylipoamide
3. Actyl group transfered to CoA
4. Lipoamide reoxidised producing FADH2 on E3
5. Reoxidation of FADH2 to FAD producing NADH.

Question 9

Where do the reactions of the Pyruvate Dehydrogenase Complex occur?

Answer 9

The Mitochondrial Matrix