Before You Begin
Question #46269
The Question
During microsporogenesis in a diploid angiosperm, a complete failure of meiotic reductional division occurs, leading to the formation of unreduced microspores. If these microspores develop into mature pollen grains and successfully fertilize a normal, wild-type female gametophyte, which of the following statements correctly describes the ploidy of the resulting structures and the most probable developmental outcome?
Options
- A.
The zygote will be 3n and the Primary Endosperm Nucleus (PEN) will be 5n, leading to a viable polyploid seed.
- B.
The zygote will be 3n and the PEN will be 4n, but the seed will likely abort due to an altered maternal-to-paternal genome ratio in the endosperm.
- C.
The zygote will be 4n and the PEN will be 5n, resulting in immediate post-zygotic reproductive isolation.
- D.
The zygote will be 2n and the PEN will be 4n, allowing normal embryogenesis to proceed without interruption.
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
Seed Embryology|Microsporogenesis Ploidy Shift|Meiotic Reductional Division
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often mechanically memorize 'Zygote = 2n, PEN = 3n' without applying the additive mathematics of syngamy and triple fusion in mutant scenarios.
Furthermore, this question tests the 'NCERT-Plus' concept of genomic imprinting in plants—the understanding that endosperm viability is highly sensitive to the maternal-to-paternal genomic ratio, which acts as a post-zygotic isolation mechanism.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Morphology of Flowering Plants - Class 11 |
| Concept | Seed Embryology |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |