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Oxidative decarboxylation of pyruvate and Citric Acid Cycle test

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LESSON 17: PYRUVATE AND CAC

LESSON 17: PYRUVATE AND CAC

Question 1 of 9

2

Which of these is not true?

Select one of the following:

  • The outer mitochondrial membrane is crossed by facilitated diffusion by cotransport with a proton

  • Pyruvate is going to be transformed into Acetyl coenzyme A and one molecule of CO2

  • The oxidative decarboxylation of pyruvate is catalyzed by pyruvate dehydrogenase complex

  • Pyruvate dehydrogenase complex is constituted by 3 different kind of enzymes and 5 different coenzymes

  • The pyruvate that is formed in glycolysis will be transferred into mitochondrial matrix

Explanation

Question 2 of 9

2

About the enzymes E1, E2 and E3, which of these is true?

Select one of the following:

  • 1.) Enzyme 1 contains TPP as coenzyme and it is involved in the oxidative decarboxylation of pyruvate

  • 2.) Enzyme 2 contains Lipoamide that is involved in the transfer of one hydroxyethyl group to CoA

  • 3.) Enzyme 3 contains as coenzyme FAD and it is involved in the regeneration of oxidative form of lipoamide

  • 1.) and 3.) are both true

  • All are true

Explanation

Question 3 of 9

1

Pyruvate is going to suffer a oxidative dicarboxylation that is catalyzed by Ez 1, and in this reaction, one molecule of CO2 is going to be released and one hydroxyethyl group is going to be linked to the coenzyme TTP of E1.

Select one of the following:

  • True
  • False

Explanation

Question 4 of 9

2

In the regulation of PDH, when PDH will be active?

Select one of the following:

  • PDH will be active when is not phosphorylated and when levels of NADH and Acetyl CoA are low.

  • PDH will be active when is phosphorylated and when levels of NADH and Acetyl CoA are low.

  • PDH will be active when is not phosphorylated and when levels of NADH and Acetyl CoA are high.

  • PDH will be active when is phosphorylated and when levels of NADH and Acetyl CoA are high.

  • Any of these

Explanation

Question 5 of 9

2

Which of these about the Citric Acid Cycle is not true?

Select one of the following:

  • CAC is cycle and it takes place in mitochondria

  • CAC is one pathway that is used in the metabolism of carbohydrates, amino acids and lipids

  • It is responsible of the production of 1 third of the total energy (ATP)

  • It is an amphipathic pathway

  • There are 3 points of regulation in the cycle

Explanation

Question 6 of 9

2

The three reaction regulated in CAC are...?

Select one of the following:

  • - Oxaloacetate condense with Acetyl CoA forming Citrate
    - Alfa-ketoglutarate suffer one oxidative decarboxylation forming Succinyl CoA
    - Malate is oxydased and one molecule of NADH is formed

  • - Citrate is transformed to its isomer that is called Isocitrate
    - Isocitrate suffer one oxidative decarboxylation and it is transformed into alfa-ketoglutarate
    - Fumarate is transformed into malate

  • - Oxaloacetate condense with Acetyl CoA forming Citrate
    - Fumarate is transformed into malate
    - Malate is oxydased and one molecule of NADH is formed

  • - Citrate is transformed to its isomer that is called Isocitrate
    - Isocitrate suffer one oxidative decarboxylation and it is transformed into alfa-ketoglutarate
    - Succinate is oxydased to fumarate

  • - Oxaloacetate condense with Acetyl CoA forming Citrate
    - Isocitrate suffer one oxidative decarboxylation and it is transformed into alfa-ketoglutarate
    - Alfa-ketoglutarate suffer one oxidative decarboxylation forming Succinyl CoA

Explanation

Question 7 of 9

2

For each molecule of AcetylCoA we finally obtain...?

Select one of the following:

  • 3NADH, 1 FADH2, 1 GTP, 2CO2: 12 ATP

  • 2NADH, 2 FADH2, 1 GTP, 2CO2: 12 ATP

  • 3NADH, 2 FADH2, 1 GTP, 2CO2: 12 ATP

  • 3NADH, 2 FADH2, 2 GTP, 2CO2: 14 ATP

  • 3NADH, 1 FADH2, 1 GTP, 1CO2: 12 ATP

Explanation

Question 8 of 9

2

Which are the enzymes that are submitted to CAC regulation?

Select one of the following:

  • Citrate synthase, malate dehydrogenase and alfa-ketoglutarate dehydrogenase complex

  • Citrate synthase, isocitrate dehydrogenase and alfa-ketoglutarate dehydrogenase complex

  • Citrate synthase, succinate dehydrogenase and alfa-ketoglutarate dehydrogenase complex

  • Citrate synthase and alfa-ketoglutarate dehydrogenase complex

  • Any of these is totally true

Explanation

Question 9 of 9

1

The inhibitors of the enzymes acting in CAC regulation rare ATP and NADH and the activator is ADP

Select one of the following:

  • True
  • False

Explanation

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