Question

In what stage of cellular respiration is most of the carbon dioxide produced?

Answer 1

The Krebs Cycle

Explanation:

The Krebs cycle or the TCA cycle produces `"2 "CO_2` for every `"1 molecule of acetyl CoA".`

This occurs in Step 3 and Step 4 of the Krebs cycle.

In Step 3, `color(orange)"isocitrate"` is oxidized to become `color(blue)"alpha-ketoglutarate"` by the rate-limiting enzyme, `color(red)"isocitrate dehydrogenase".`

In Step 4, `color(blue)"alpha-ketoglutarate"` undergoes a redox reaction, oxidizing to become `color(magenta)"succinyl-CoA"`, also releasing `CO_2` in the process.

Each step generates the coenzyme, `"NADH"`, an electron carrier which is going to be important in the next stage of cellular respiration, the electron transport chain.