Is sucrose an endogenous energy source for yeast?

Sucrose is not an endogenous energy source for yeast; rather, it is an external carbohydrate that yeast can utilize for energy. Yeast cells, particularly Saccharomyces cerevisiae, can metabolize sucrose after it is hydrolyzed into glucose and fructose by the enzyme invertase. Once broken down, these simpler sugars can be fermented to produce energy. Therefore, while yeast can use sucrose, it does not produce it internally.