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Multiple Choice
Under what conditions do yeast cells switch from aerobic respiration to fermentation?
A
When oxygen is abundant
B
When oxygen is scarce
C
When glucose levels are low
D
When carbon dioxide levels are high
Verified step by step guidance
1
Understand the basic metabolic pathways: Yeast cells can undergo aerobic respiration or fermentation. Aerobic respiration requires oxygen and produces more ATP, while fermentation occurs in the absence of oxygen and produces less ATP.
Identify the role of oxygen: Oxygen is a key factor in determining whether yeast cells will undergo aerobic respiration or fermentation. When oxygen is abundant, yeast cells prefer aerobic respiration due to its higher energy yield.
Recognize the switch to fermentation: When oxygen becomes scarce, yeast cells switch to fermentation. This allows them to continue producing ATP, albeit less efficiently, by converting glucose into ethanol and carbon dioxide.
Consider glucose levels: While glucose is necessary for both aerobic respiration and fermentation, the switch between these pathways is primarily influenced by oxygen availability rather than glucose levels.
Evaluate carbon dioxide levels: High carbon dioxide levels are a result of fermentation, not a cause for the switch. The switch is primarily driven by the scarcity of oxygen.