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Question #45800
The Question
In an ecosystem experiencing a severe drop in primary productivity, an apex predator faces a critical glucose deficit due to the 10% energy transfer law. During a sudden, intense sprint, its skeletal muscles rapidly fatigue due to a shift towards anaerobic glycolysis. Which of the following statements correctly identifies the molecular consequence of this metabolic shift on the sarcomere's cross-bridge cycle?
Options
- A.
The resulting accumulation of lactic acid lowers intracellular pH, causing H+ ions to interfere with Ca2+ binding to Troponin C and inhibiting myosin ATPase.
- B.
The rapid depletion of ATP prevents the binding of the energized myosin head to the exposed active sites on F-actin, halting the power stroke.
- C.
Anaerobic glycolysis produces excess CO2, which binds to the allosteric site of myosin ATPase, preventing the hydrolysis of ATP.
- D.
The lack of aerobic energy yield prevents the release of Ca2+ from the sarcoplasmic reticulum, keeping the tropomyosin-troponin complex bound to the myosin head.
Check Your Answer
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
Mitochondrial_Respiration|ATP_Synthase|10_Percent_Law
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize 'lactic acid causes fatigue' without understanding the molecular mechanism (pH drop affecting protein conformation and Ca2+ binding).
Additionally, this question tests the 'Common Misconception' regarding the role of ATP in muscle contraction; students frequently assume ATP is needed to form the cross-bridge, whereas NCERT clearly states ATP binding causes the cross-bridge to detach.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Locomotion and Movement - Class 11 |
| Concept | Cross-bridge Cycling Energy |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |