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Question #45319
The Question
The filiform apparatus plays a crucial role in pollen-pistil interaction by guiding the pollen tube into the synergid. To study the termination of this guidance (the angiosperm 'polyspermy block'), a researcher pollinates a normal diploid (2n) plant with artificially induced tetraploid (4n) pollen. They observe that the signaling fails to terminate, leading to the entry of multiple pollen tubes into a single embryo sac. Which of the following statements regarding this reproductive event is INCORRECT?
Options
- A.
The filiform apparatus consists of special cellular thickenings at the micropylar tip of the synergids that secrete chemoattractants.
- B.
The altered stoichiometry of the polyploid pollen tube contents disrupts the signaling feedback loop required for the rapid degeneration of the receptive synergid.
- C.
The continuous attraction of pollen tubes occurs because the polyploid male gametes fuse with the synergid nucleus, delaying its programmed cell death.
- D.
In a normal diploid cross, the degeneration of the penetrated synergid is essential to stop further pollen tube attraction and ensure strict double fertilization.
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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
Synergids|Filiform apparatus|Primary Endosperm Nucleus
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often confuse the spatial location of pollen tube discharge (into the synergid) with the actual fertilization events (fusion).
The trap exploits the misconception that a male gamete fuses with the synergid nucleus to cause its degeneration.
In reality, synergid degeneration is a signaling/mechanical response to the tube's entry and discharge, not a nuclear fusion event.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Sexual Reproduction in Flowering Plants - Class 12 |
| Concept | Pollen-Pistil Interaction |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |