Question

acid cycle (see the figure)? The figure shows the scheme of the citric acid cycle. Starting from acetyl CoA, it transforms into citrate, then isocitrate, then alpha-ketoglutarate, then succynil CoA, then succinate, then fumarate, then malate, then oxaloacetate and then forms a cycle with the transformation of oxaloacetate into citrate in the presence of acetyl CoA. One molecule of CO2 is formed at the stage of formation of alpha-ketoglutarate and one is formed at that of succinyl CoA. For each mole of glucose (C6H12O6) completely oxidized by cellular respiration, how many moles of CO2 are released in the citric acid cycle (see the figure)? 2 3 4 6 12

Answer 1

Answer:

4  

Step-by-step explanation:

The reactions are:

Glycolysis:                      1 glucose ⟶ 2 pyruvate

Link reaction:         2 × [1 pyruvate ⟶ 1 acetyl CoA]

Citric acid cycle: 2 × [1 AcetylCoA ⟶ 2 CO₂]

Now, add the reactions, cancelling species that occur on both sides of the reaction arrow,

             1 glucose ⟶ 2 pyruvate

           2 pyruvate ⟶ 2 acetyl CoA

        2 AcetylCoA ⟶ 4 CO₂

Overall : 1 glucose ⟶ 4 CO₂

For each mole of glucose, four molecules of CO₂ are released in the citric acid cycle.