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Question #45367
The Question
A transgenic male mouse is engineered to express a specific double-stranded RNA (dsRNA) in its primary spermatocytes. This dsRNA is perfectly complementary to the mRNA transcript of acrosin, an essential acrosomal serine protease. Assuming the RNA interference (RNAi) pathway is fully active, which of the following represents the most accurate physiological outcome and its underlying mechanism?
Options
- A.
A. The mouse will exhibit azoospermia because the dsRNA-RISC complex binds to the acrosin promoter, permanently blocking its transcription by RNA polymerase II.
- B.
B. The spermatozoa will be morphologically normal but functionally sterile, as the RNAi pathway prevents the translation of acrosin mRNA, leaving the Golgi-derived acrosome deficient in this enzyme.
- C.
C. The spermatozoa will fail to undergo capacitation in the female reproductive tract because the absence of acrosin prevents the removal of sterols from the sperm membrane.
- D.
D. The primary spermatocytes will undergo apoptosis due to the accumulation of untranslated acrosin mRNA in the rough endoplasmic reticulum, halting spermatogenesis.
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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
Acrosin|dsRNA|RISC Complex
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Distinguishing between post-transcriptional silencing (RNAi) and transcriptional blocking, alongside differentiating the Acrosome Reaction (enzyme-dependent zona penetration) from Capacitation (membrane sterol efflux).
A common misconception is assuming that silencing a single enzyme gene halts the entire cellular developmental pathway (spermatogenesis) rather than just causing a highly specific functional deficit.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Human Reproduction - Class 12 |
| Concept | Acrosomal Enzyme Activation |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |