what happens to the carbon dioxide produced in breaking down pyruvic acid?

Answer 1

In the human body, the CO2 diffuses out of the mitochondria into the cytoplasm. From the cytoplasm, it diffuses through the plasma membrane into the interstitial fluid, and into the bloodstream. The circulatory system takes the CO2 to the lungs where it is diffused into the alveoli and is exhaled into the environment.

In bacteria and yeast, the waste product of CO2 is simply excreted into the environment. The CO2 getting trapped in the gluten is what makes bread rise and gives it's porous texture. In a liquid, the CO2 is dissolved and it's what gives beer and champagne it's effervescence.

Answer 2

Depends on the reaction vessel. If the vesel is open, it will escape into the surrounding air. If the vessel is closed, it will accumulate in the reaction vessel.