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Question #45326
The Question
During the development of the free nuclear endosperm in Cocos nucifera, the Primary Endosperm Nucleus (PEN) undergoes rapid successive mitotic divisions without cytokinesis. If a targeted mutation eliminates the 3' → 5' exonuclease activity of DNA polymerase during this syncytial phase, which of the following is the most likely developmental consequence?
Options
- A.
The endosperm will immediately undergo cytokinesis to isolate the mutated nuclei, forming a premature cellular endosperm.
- B.
The seed will likely abort because catastrophic replication stress prevents the PEN from reaching the nuclear density threshold required for cellularization.
- C.
The PEN will switch to a helobial mode of development, forming a transverse wall immediately after the first division to limit mutation spread.
- D.
The embryo will develop normally by bypassing the endosperm and directly absorbing nutrients from the persistent nucellus (perisperm).
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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
Free Nuclear Endosperm|Coconut Water|DNA Replication
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Integrating Molecular Basis of Inheritance (DNA Pol proofreading) with Sexual Reproduction in Flowering Plants (Endosperm cellularization).
Students often memorize endosperm types but fail to realize that the 'free nuclear' phase is essentially a massive, rapid DNA replication event.
The common misconception is assuming that mutations would merely create a 'mutated endosperm' rather than halting the developmental sequence entirely due to replication checkpoint failures and the inability to reach the nuclear density required for cellularization.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Sexual Reproduction in Flowering Plants - Class 12 |
| Concept | Endosperm Development Sequencing |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |