When an organism such as a yeast lives by fermentation, it converts the pyruvate from glycolysis into a different compound, such as alcohol, which is then exported from the cell. Why doesn't it secrete the pyruvate directly

The conversion is required to regenerate the molecules needed for glycolysis.

Explanation:

1. Yeast lives by fermentation, in which the glycolysis produce pyruvate and the pyruvate is further broke down into different compounds like alcohol.

2. There is no TCA cycle in yeast.

3. Yeast cell export alcohol, because while converting pyruvate into alcohol, it regenerate the molecules which are required in glycolysis.

4. This conversion isrequired to regenerate the molecules needed for glycolysis.