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Question #45926
The Question
A novel pharmacological agent specifically inhibits the malate-aspartate shuttle in highly active aerobic tissues, such as cardiac muscle, while oxygen supply remains abundant. Which of the following represents the most immediate and accurate metabolic consequence of this inhibition?
Options
- A.
The net ATP yield per glucose molecule drops to 2, accompanied by cytosolic accumulation of lactic acid to regenerate NAD+.
- B.
Glycolysis halts completely due to the absolute inability to regenerate cytosolic NAD+ through oxidative phosphorylation.
- C.
The electron transport chain ceases to function entirely, leading to a complete halt of the Tricarboxylic Acid (TCA) cycle.
- D.
Pyruvate accumulates in the mitochondrial matrix, shifting the cellular metabolism towards alcoholic fermentation.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Shuttle System Impact|NADH|Mitochondrial Matrix
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often assume that the mere presence of oxygen guarantees complete aerobic respiration.
This question tests the understanding of cellular compartmentalization—specifically, that glycolytic NADH must physically transfer its electrons into the mitochondria via shuttles.
Failing this, the cell must resort to lactic acid fermentation to maintain redox balance (NAD+ regeneration), drastically reducing ATP yield despite normoxic conditions.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Respiration in Plants - Class 11 |
| Concept | Shuttle System Impact |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |