Anaerobic respiration in yeast produces alcohol from glucose

Steps:

• Identify process: Anaerobic respiration by yeast (fungus) ferments glucose to ethanol and carbon dioxide.
• Match P: Organism is fungus (yeast), not bacteria or viruses.
• Match Q: Substrate is glucose, the simple sugar directly used in fermentation.
• Match R: Gas produced is carbon dioxide, collected in the apparatus.

Why C is correct:

• Fermentation equation: C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂, where yeast converts glucose to alcohol and CO₂ under anaerobic conditions.

Why the others are wrong:

• A: Amylase digests starch to glucose, but apparatus uses glucose directly; oxygen inhibits anaerobic process.
• B: Bacteria typically produce lactic acid, not alcohol; nitrogen is irrelevant to respiration.
• D: Viruses do not perform respiration; sucrose requires hydrolysis first; water vapor is not the primary gas output.

Final answer: C