What do yeast cells primarily consume during fermentation?

Yeast cells primarily consume sugars during fermentation because sugars serve as their primary source of energy. When yeast is introduced to a sugar-rich environment, typically in the form of glucose or other fermentable sugars, they metabolize these sugars to produce energy. This process generates alcohol and carbon dioxide as byproducts, which is fundamental in applications such as baking and brewing. In baking, the carbon dioxide is what causes the dough to rise, while in brewing, the alcohol is the desired product.

Fats, proteins, and minerals are not the main substrates for yeast fermentation. While yeast can utilize proteins and fats in some metabolic pathways, their primary energy conversion mechanism relies on sugars. Thus, the fermentation process is heavily dependent on the availability of sugars, making this choice the correct answer.