Fermentation Original Scenario-Based Practice

Questions

1. 1.

   A bio-engineering team exploring an oxygen-depleted subterranean fissure deploys synthetic yeast cells engineered to metabolize glucose within an anaerobic chamber. The researchers observe that although oxygen is completely absent, the cells maintain a steady rate of substrate-level ATP production without depleting cytoplasmic reserves. They determine that this continuous energy generation depends strictly on the recycling of essential electron carriers through alcoholic fermentation. Which specific chemical event directly enables these cells to sustain glycolysis under these anaerobic conditions?

   • A) Donating electrons from NADH directly to an oxygen-dependent inner mitochondrial transport chain
   • B) Converting pyruvate into acetyl-CoA so that the citric acid cycle can generate excess high-energy electrons
   • C) Reducing acetaldehyde using electrons from NADH to produce ethanol and regenerate free NAD+
   • D) Cleaving accumulated ethanol into inorganic phosphate and lactate to phosphorylate ADP directly

Answers and step-by-step solutions appear after you finish the test.