Yeast mushrooms need sugar to reproduce, then why do they multiply in the dough?

First of all, due to the fact that a little sugar is added to the dough during kneading to speed up the process of yeast multiplication. But if sugar is not added, the yeast will still act, although a little slower. This is due to the fact that glucose is formed during the breakdown of starch, which is quite abundant in flour. If you take a little flour and put it in the mouth, then after a while, under the action of the digestive enzymes of saliva, carbohydrates will begin to break down into glucose. This is done with the help of yeast enzymes.