Baker's yeast is a single-celled ascomycete that is used in bread making. Why does yeast make bread dough rise?

Presence of CO2 in the dough.

Explanation:

Yeast cells thrive on simple sugars. As the sugars are metabolized, carbon dioxide and alcohol.

chemical process known as fermentation.

Equation of Fermentation reaction:

C6H12O6(s) --> 2C2H5OH(aq) + 2CO2(g)

Tiny air cells fill with carbon dioxide are released into the bread dough, making it rise.

enzyme active site and substrate specificity

enzymes bind with chemical reactants called substrates. there may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. in some reactions, a single-reactant substrate is broken down into multiple products

the answer to your question is tooth decay.