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Question #45489
The Question
An angiosperm species that typically sheds pollen at the 3-celled stage is subjected to extreme heat stress just prior to anthesis. This thermal disruption specifically denatures the regulatory proteins (Cyclin-CDK complexes) required for the G2/M transition within the developing pollen grain. Which of the following represents the most direct consequence of this event?
Options
- A.
The microspore mother cell arrests at Prophase I, preventing the formation of microspore tetrads.
- B.
The vegetative cell fails to undergo mitosis, preventing the elongation of the pollen tube upon reaching the stigma.
- C.
The generative cell fails to divide mitotically, resulting in a pollen grain incapable of completing double fertilization.
- D.
The pollen grain fails to synthesize sporopollenin, leading to rapid desiccation of the exine layer.
Check Your Answer
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
Generative_Cell|Thermal_Tolerance_Ranges|Pollen_Viability
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Distinguishing between the developmental timelines of microsporogenesis (meiosis) and microgametogenesis (mitosis).
The trap relies on the student's ability to pinpoint exactly which cell (generative vs. vegetative) undergoes the final mitotic division and the precise timing of tapetal functions versus internal pollen grain divisions.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Sexual Reproduction in Flowering Plants - Class 12 |
| Concept | Generative Cell Division |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |