During which stage in the complete oxidation of glucose are the...

In glycolysis 4 ATP and $2 \mathrm{NADH}_2$ molecules are formed. These $2 \mathrm{NADH}_2$ molecules go to electron transport chain. In oxidative decarboxylation no ATP molecule is formed but two molecules of $\mathrm{NADH}_2$ are formed from two molecules of pyruvate. These two $\mathrm{NADH}_2$ go to electron transport chain. In Krebs cycle 2 ATP, $6 \mathrm{NADH}_2$ and $2 \mathrm{FADH}_2$ molecules are formed from two molecule of acetyl Co-A. These $\mathrm{NADH}_2$ and $\mathrm{FADH}_2$ go to electron transport chain. In electron transport chain all $\mathrm{NADH}_2$ and $\mathrm{FADH}_2$ pass to electron carriers and yield 3 ATP and 2 ATP molecules per $\mathrm{NADH}_2$ and $\mathrm{FADH}_2$ respectively. Thus, 4 ATP are formed in glycolysis 2 ATP in Krebs cycle and 34 ATP from electron transport chain 40 ATP 2 ATP molecules are used during glycolysis. So, net gain of ATP molecules during one complete oxidation of a glucose molecule is 38 ATP.