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Question #45431
The Question
Successful fertilization in humans requires the secondary oocyte to complete Meiosis II, a process strictly dependent on intracellular Ca2+ oscillations. The oocyte's competence to respond to these calcium pulses is primed by the pre-ovulatory hormonal environment. Which of the following statements regarding this physiological process is INCORRECT?
Options
- A.
The fertilizing sperm triggers a Ca2+ surge that primarily originates from the oocyte's smooth endoplasmic reticulum.
- B.
Inadequate pre-ovulatory estrogen priming can lead to a failure of oocyte activation despite successful sperm penetration.
- C.
The intracellular Ca2+ oscillations directly inhibit the Anaphase Promoting Complex (APC), maintaining the oocyte in Metaphase II until the pronuclei fuse.
- D.
The calcium-dependent activation of the oocyte simultaneously triggers the exocytosis of cortical granules to prevent polyspermy.
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
Calcium_Oscillations|Oocyte_Activation|Corpus_Luteum
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often confuse the roles of APC (Anaphase Promoting Complex) and MPF (Maturation Promoting Factor) during cell cycle arrest.
The secondary oocyte is arrested in Metaphase II due to high MPF activity.
Calcium oscillations activate APC, which destroys MPF, thereby breaking the arrest.
Stating that calcium 'inhibits' APC perfectly flips the molecular logic, creating a high-yield 'Not/Except' trap that tests the integration of 'Cell Cycle' and 'Human Reproduction' chapters.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Chemical Coordination and Integration - Class 11 |
| Concept | Calcium Homeostasis |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |