Before You Begin
Question #45803
The Question
A patient suffering from severe hypokalemia (abnormally low extracellular ) exhibits profound skeletal muscle weakness, despite having normal intracellular ATP levels and no lactic acid accumulation. Based on the mechanism of excitation-contraction coupling, what is the primary reason for this failure of muscle contraction?
Options
- A.
The sarcolemma becomes hyperpolarized, increasing the threshold for action potential generation and preventing release from the sarcoplasmic reticulum.
- B.
The myosin heads are unable to hydrolyze ATP, preventing the formation of the cross-bridge with the active sites on F-actin.
- C.
The motor end plate undergoes continuous depolarization, leading to a state of sustained contraction or tetany.
- D.
The troponin subunit fails to bind with due to competitive inhibition by intracellular potassium ions.
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
Sarcomere|K+ Ions|Neuromuscular Junction
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often associate muscle weakness exclusively with ATP depletion or lactic acid accumulation (standard NCERT fatigue).
The pivot here is recognizing that the electrical prerequisite (Action Potential via ionic flux) must precede the mechanical sliding filament mechanism.
A common misconception is confusing the effects of different ion imbalances; for instance, failing to distinguish that hypocalcemia causes tetany (depolarization ease) while hypokalemia causes flaccid paralysis (hyperpolarization).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Locomotion and Movement - Class 11 |
| Concept | Muscle Fatigue Factors |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |