Krebs cycle or Citric acid cycle Enzyme Labeling Diagram Quiz

 This labelled diagram quiz on Krebs cycle is designed to assess your knowledge on enzymes in Krebs cycle. Choose the best answer from the four options given. When you've finished answering as many of the questions as you can, scroll down to the bottom of the page and check your answers by clicking ' Score'.  Percentage score will be displayed along with right answers. You can watch this video for better understanding.

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1. The pyruvate formed during glycolysis enters mitocondria and is converted to Acetyl CoA. The enzyme in this link reaction is
Pyruvic acid dehydrogenase
Acetate dehydrogenase
Isocitrate dehydrogenase
Aconitase

2.In the first step of Krebs cycle, Acetyl CoA (C2) is added to oxaloacetate (C4) to form citrate (C6). The enzyme 1 involved in this step is
Aconitase
Citrate synthase
Acetate dehydrogenase
Isocitrate dehydrogenase

3. The second step of Krebs cycle is the conversion of Citrate (C6) to isocitrate (C6). The enzyme 2 involved in this step is
Citrate synthase
Citrate dehydrogenase
Isocitrate dehydrogenase
Aconitase

4. In the third step of Krebs cycle, Isocitrate (C6) is converted into alphaketoglutarate (C5) by dehydrogenation and decarboxylation. The enzyme 3 involved in this step is
Citrate dehydrogenase
Isocitrate dehydrogenase
α-ketoglutarate dehydrogenase
Acetate dehydrogenase

5. In the Fourth step of Krebs cycle, α-ketoglutarate (C5) is oxidatively decarboxylated to form succinyl-CoA (C4), a high energy compound. The enzyme 4 involved in this step is
α-ketoglutarate dehydrogenase
Isocitrate dehydrogenase
Acetate dehydrogenase
Aconitase

6. The Fifth step of Krebs cycle is the conversion of Succinyl CoA(C4) to succinate (C4) by substrate level phosphorylation . The enzyme 5 involved in this step is
Succinyl-CoA synthetase
Succinyl-CoA dehydrogenase
Fumarase
Isocitrate dehydrogenase

7. In the sixth step of Krebs cycle, Succinate(C4) is converted to fumarate (C4) by dehydrogenation. The enzyme 6, located in the inner mitochondrial membrane is
Succinyl-CoA dehydrogenase
Succinate synthase
Succinate dehydrogenase
Fumarase

8. In the seventh step of Krebs cycle, Fumarate(C4) is converted to malate(C4) with the addition of water. The enzyme 7, involved in this step is
Fumarase
Aconitase
Malate dehydrogenase
Malate synthase

9. In the final eighth step, Malate (C4) is converted to oxaloacetate(C4) with NADH synthesis.The enzyme involved is
Malate dehydrogenase
Malate synthase
oxaloacetate synthase
oxaloacetate dehydrogenase

10. Krebs cycle is also called as
Citric acid cycle
TCA cycle
both a and b
none of these

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