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Question #47433
The Question
Given below are two statements regarding the ionic basis of cellular events in animal physiology:
Statement I: The immediate 'fast block' to polyspermy in an ovum and the depolarization phase of an axonal action potential are both mediated by the rapid efflux of K+ ions. Statement II: The 'slow block' to polyspermy (cortical reaction) and the exocytosis of neurotransmitters at a chemical synapse both strictly require an intracellular surge of Ca2+ ions.
Choose the correct option:
Options
- A.
Both Statement I and Statement II are correct.
- B.
Both Statement I and Statement II are incorrect.
- C.
Statement I is correct but Statement II is incorrect.
- D.
Statement I is incorrect but Statement II is correct.
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
Polyspermy Prevention Mechanisms|Synaptic Delay Determinant|Calcium signaling
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize 'depolarization' and 'polyspermy block' as abstract concepts without linking them to their specific ionic drivers (Na+ vs Ca2+).
The trap in Statement I is the phrase 'efflux of K+' instead of 'influx of Na+', testing precise reading of ion kinetics.
The synthesis requires mapping the mechanism of exocytosis (cortical granules in ova vs. synaptic vesicles in neurons) to the same universal Ca2+ trigger, bridging NCERT Human Reproduction with Neural Control and Coordination.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Neural Control and Coordination - Class 11 |
| Concept | Synaptic Delay Determinant |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |