O Levels Biology (5090)•5090/12/M/J/23
Explanation
Anaerobic respiration in yeast produces alcohol and CO2 from sugar
Steps:
- Recall anaerobic respiration in yeast is alcoholic fermentation without oxygen.
- Identify substrate as glucose (sugar) broken down for energy.
- Note products are ethanol (alcohol) and carbon dioxide (CO2) to regenerate NAD+.
- Match to option listing sugar used and alcohol/CO2 produced.
Why C is correct:
- Aligns with fermentation equation: C6H12O6 → 2C2H5OH + 2CO2, where sugar is substrate and alcohol/CO2 are products.
Why the others are wrong:
- A: Omits substrate (sugar); water not produced in anaerobic yeast respiration.
- B: Lactic acid from bacterial/muscle fermentation, not yeast; water absent.
- D: Water and CO2 from aerobic respiration, not anaerobic in yeast.
Final answer: C
Topic: Anaerobic respiration
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