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Question #46566
The Question
During industrial ethanol production, a cooling system failure causes the bioreactor temperature to exceed the thermal tolerance of the yeast, specifically denaturing the enzyme pyruvate decarboxylase. Which of the following represents the most immediate biochemical consequence of this thermal stress?
Options
- A.
Glycolysis arrests due to the inability to regenerate NAD+ from NADH, as the formation of the intermediate electron acceptor, acetaldehyde, is blocked.
- B.
Alcohol dehydrogenase directly utilizes the accumulated pyruvic acid as an electron acceptor to maintain the continuous regeneration of NAD+.
- C.
The metabolic flux shifts towards the mitochondrial electron transport chain to oxidize the accumulated NADH, independent of oxygen availability.
- D.
The yeast cells immediately switch to lactic acid fermentation, utilizing lactate dehydrogenase to sustain the optimal energetic yield of 2 ATP.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Comparative_Analysis
Sharpen your ability to evaluate multiple scenarios and distinguish between competing potential answers.
Concepts Behind This Question
Saccharomyces_cerevisiae|Thermal Tolerance Ranges|Optimal Foraging Theory
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize the net equation of fermentation without understanding the sequential enzymatic dependency.
The core misconception is failing to recognize that the first enzyme (pyruvate decarboxylase) generates the specific electron acceptor (acetaldehyde) required by the second enzyme (alcohol dehydrogenase) to regenerate NAD+.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Microbes in Human Welfare - Class 12 |
| Concept | Alcoholic Beverage Fermentation Source |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |