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Question #45912
The Question
A researcher is comparing the net ATP yield from the complete aerobic oxidation of one molecule of glucose in a human hepatocyte and a skeletal muscle fiber. They observe a net yield of 38 ATP in the hepatocyte and 36 ATP in the skeletal muscle. Which of the following statements accurately explains this quantitative discrepancy?
Options
- A.
In skeletal muscle, reducing equivalents from cytosolic NADH are transferred to mitochondrial FAD via the glycerol-phosphate shuttle, bypassing Complex I.
- B.
Hepatocytes utilize the malate-aspartate shuttle to actively transport intact cytosolic NADH molecules directly into the mitochondrial matrix.
- C.
Skeletal muscle utilizes the malate-aspartate shuttle, which transfers electrons to mitochondrial NAD+, yielding 3 ATP per cytosolic NADH.
- D.
In hepatocytes, the glycerol-phosphate shuttle transfers electrons from cytosolic NADH to mitochondrial FAD, bypassing Complex I of the ETS.
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
Malate-Aspartate_Shuttle|NADH|FAD
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize the '36 or 38 ATP' rule from NCERT but fail to understand the biochemical basis (tissue-specific shuttle systems).
The primary trap (Option B) exploits the common misconception that the NADH molecule itself physically crosses the inner mitochondrial membrane, whereas shuttle systems only transfer the reducing equivalents.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Respiration in Plants - Class 11 |
| Concept | Chemiosmotic ATP Yield |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |