2017 Biochemistry - Oxidation of Pyruvate and TCA Cycle Flashcards Preview

2017 Semester 1 > 2017 Biochemistry - Oxidation of Pyruvate and TCA Cycle > Flashcards

Flashcards in 2017 Biochemistry - Oxidation of Pyruvate and TCA Cycle Deck (11):
1

Where does the pyruvate dehydrogenase complex "live" in the cell?

Inside the mitochondrion

2

How many enzymes and cofactors are involved in the PDH Complex?

3 Enzymes
-pyruvate dehydrogenase
-dihydrolipoyl transacetylase
-dihydrolipoyl dehydrogenase

5 Cofactors
-Thiamine pyrophosphate
-Lipoic acid
-Coenzyme A
-FAD
-NAD+

3

Where does the TCA cycle take place?

Matrix of Mitochondria

4

What are the inputs and outputs of the TCA cycle?

Inputs:
-Acetyl CoA
-H20

Outputs:
-2-CO2
-3-NADH
-FADH2
-GTP

5

What are the irreversible steps of TCA cycle and which enzymes are involved?

Step 1: Citrate Synthase
Step 6: a-Ketoglutarate dehydrogenase complex

6

What is the rate limiting step of TCA cycle? What is produced at this step?

Isocitrate dehydrogenase
Produces first NADH and first CO2

7

What inhibits Citrate synthase?

Succinyl-CoA

8

What stimulates and inhibits Isocitrate Dehydrogenase?

Stimulates: ADP
Inhibits: ATP

9

What inhibits a-KGDH?

Inhibits: Succinyl-CoA, NADH, GTP

10

What is the purpose of the pyruvate dehydrogenase multienzyme complex?

Oxidatively decarboxylate pyruvate into Acetyl-CoA

11

How many ATP molecules are produced per molecule of glucose using the TCA cycle?

Glycolysis: 8
PHD Complex: 6
TCA Cycle (only): 24
Total: 38 ATP