Question

How many times oxidative decarboxylation occurs during breakdown of glucose?

Answer 1

The following reactions show the oxidative decarboxylation that occurs during the breakdown of glucose molecule:
1) In aerobic respiration, when acetyl CoA enters the citric acid cycle, it oxidized to ${\text{CO}}_2$

2) In the Kreb’s cycle, when Isocitric is oxidized to ${\text{NAD}}^{+}$ and ${\text{NAD}}^{+}$ is reduced from NADH, at this time ${\text{CO}}_2$ is released and alpha-ketoglutarate is formed.

3) When CoA oxidizes alpha-ketoglutarate and produce succinyl CoA, again ${\text{CO}}_2$ is released when ${\text{NAD}}^{+}$ is reduced from NADH.

So, in total three time oxidative decarboxylation occurs.
Hence, the correct answer is option “C” – Three.