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Question #47658
The Question
To maintain cytosolic redox balance under anaerobic conditions, both yeast and human muscle cells rely on fermentation pathways. Which of the following statements regarding these processes is INCORRECT?
Options
- A.
Both homolactic and ethanolic fermentation pathways release less than seven percent of the energy stored in a glucose molecule.
- B.
In yeast, pyruvic acid decarboxylase acts first to release CO2, followed by the action of alcohol dehydrogenase.
- C.
During lactic acid fermentation in muscles, lactate dehydrogenase catalyzes the reduction of pyruvic acid while simultaneously reducing NAD+ to NADH + H+.
- D.
The fundamental physiological role of both pathways is to act as an electron sink, regenerating NAD+ to ensure the uninterrupted operation of glycolysis.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Evolutionary_Exception
Tackle problems where standard rules evolve or change based on specific environmental constraints.
Concepts Behind This Question
Saccharomyces cerevisiae | Ethanol Fermentation | NAD+ Pool
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize that 'reduction' happens during fermentation (pyruvate to lactate) but fail to track the inverse redox state of the coenzyme.
If the substrate is reduced, the coenzyme (NADH) must be oxidized to NAD+.
The trap exploits the functional overlap of redox terminology and tests the exact mechanism of cytosolic redox balance.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Respiration in Plants - Class 11 |
| Concept | Glycolysis Redox Balance |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |