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Question #45586
The Question
In an angiosperm where pollen is shed at the 2-celled stage, a severe heat shock on the stigma causes complete depolymerization of spindle fibers within the growing pollen tube. Which of the following is the most likely genetic consequence during double fertilization?
Options
- A.
The generative cell fails to undergo meiosis, resulting in a diploid zygote and a tetraploid primary endosperm nucleus.
- B.
Non-disjunction during generative cell mitosis produces aneuploid male gametes, leading to developmental arrest of the embryo or endosperm.
- C.
The vegetative nucleus undergoes unequal division, failing to guide the pollen tube to the filiform apparatus of the synergids.
- D.
Syngamy proceeds normally using the vegetative nucleus, while triple fusion fails due to the absence of functional male gametes.
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
Mendelian Gamete Frequency|Heat Shock Thermal Gradient|Generative Cell Division
Why This Question Is Tricky
Common Mistakes
The 'Conceptual Pivot' is distinguishing between the types of cell division in microsporogenesis vs. microgametogenesis.
Students often reflexively associate 'gamete formation' and 'spindle disruption' with meiosis (Option A trap).
However, in angiosperms, male gametes are formed via mitosis of the already haploid generative cell.
Furthermore, it tests the strict functional boundaries of the vegetative and generative cells.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Principles of Inheritance and Variation - Class 12 |
| Concept | Mendelian Gamete Frequency |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |