Before You Begin
Question #45483
The Question
During an in vitro pollen germination experiment, a researcher adds a specific calcium channel blocker to the nutrient medium. Which of the following will be the most direct and immediate consequence of this treatment on the pollen grain?
Options
- A.
The pecto-cellulosic intine will fail to emerge through the germ pore due to the disruption of the apical Ca2+ gradient and localized vesicle fusion.
- B.
The sporopollenin-rich exine will fail to rupture, preventing the vegetative cell from elongating into a pollen tube.
- C.
The generative cell will fail to undergo mitosis to form two male gametes due to the absence of calcium-dependent spindle fibers.
- D.
The filiform apparatus will fail to secrete the chemotropic substances required to dissolve the exine at the germ pore.
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
Pollen Wall Chemistry|Calcium Homeostasis|Secondary Messenger Cascade
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often misunderstand the mechanics of pollen germination, assuming the hard exine must be 'broken' or 'dissolved' by enzymes.
They also frequently fail to integrate concepts from the Mineral Nutrition chapter (Calcium's role in membrane function and tip growth) with the Sexual Reproduction chapter.
The trap in Option B exploits the misconception of 'exine rupture', while Option A correctly identifies that the intine simply extends through the germ pore, driven by Ca2+-dependent tip growth dynamics.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Sexual Reproduction in Flowering Plants - Class 12 |
| Concept | Pollen Wall Chemistry |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |