1 Figure 162 Pyruvate dehydrogenase contains how many enzyme

1. Figure 16-2. Pyruvate dehydrogenase contains how many enzymes? 2. Which of the following is NOT true of the reaction catalyzed by the pyruvate dehydrogenase complex? point) O Both NAD+ and a flavin nucleotide act as electron carriers. O Two different cofactors containing-SH groups participate. O Biotin participates in the decarboxylation. The substrate is held by the lipoyllysine \"swinging arm O The reaction occurs in the mitochondrial matrix. 3. Which of the below is NOT required for the oxidative decarboxylation of pyruvate to form acety-CoA? CoA-SH O NAD. FAD Lipoic acid ATP

Solution

1.The correct answer is:The correct answer is:3

Reason: The three enzymes are pyruvate dehydrogenase, dihydrolipoyl transacetylase and dihydrolipoyl dehydrogenase

2.The correct answer is:Biotin participates in the decarboxylation.

Reason: Biotin does not participate in the above step.

3.The correct answer is:ATP.

Reason: ATP is not required for the abobe step.

4.The correct answer is:6

Reason: Citrate contains 6 carbon atoms.

5.The correct answer is:aconitase

Reason:Aconitase converts citrate to isocitrate.

6.The correct answer is:Isocitrate dehydrogenase and alpha-keto glutarate dehydrogenase.

Reason:These two enzymes participate in oxidative decarboxylation process.

7.The correct answer is:They all require ATP.

Reason:The mentioned enzymes carry out the reactions without using ATP.

8.The correct answer is:Succinyl CoA synthetase.

Reason:Succinyl CoA synthetase forms succinate and ATP by substarte level phosphorylation.

9.The correct answer is:Succinate dehydrogenase.

Reason:Succinate dehydrogenase catalyses reaction in which FADH2 is formed.

10.The correct answer is :L-malate

Reason: Fumarase converts fumarate to L -malate.

11.The correct answer is:oxaloacetate.

Reason:Malate dehydrogenase oxidises malate to 4 carbon oxaloacetate.

12.The correct answer is: two carboxyl groups derived from oxaloacetate.

Reason:The above answer is correct as carboxyl groups of oxaloacetate form carbon dioxide.

13.The correct answer is:1 mol of FADH2.

Reason: 1 mol of FADH2 is produced in the above step.