Question

How would you demonstrate that yeast can respire both aerobically and anaerobically?

Answer 1

Yeast can respire both aerobically and anaerobically. It obtains more energy from aerobic respiration than anaerobic respiration. In absence of air, it continues to respire anaerobically. In bread-making, the yeast starts first with aerobic respiration. It produces water and carbon dioxide. This results in the dough rise. It then starts anaerobic respiration in absence of air. It produces ethanol when it respires anaerobically. Hence, respiration of yeast can be demonstrated by the product produced. Yeast produces water and carbon dioxide aerobically and anaerobically, it produces ethanol.