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Question #45961
The Question
A plant physiologist observes that a specific genetic mutant fails to develop lateral roots even after the application of synthetic auxins. Histological sectioning of the root reveals that the pericycle cells are locked in a state where chromosomes are aligned at the equatorial plate. Which of the following is the most scientifically accurate explanation for this phenotype?
Options
- A.
A mutation in the Anaphase Promoting Complex (APC) prevents the degradation of securin, arresting pericycle cells in metaphase.
- B.
The absence of auxin-efflux carriers prevents the accumulation of auxin in the endodermis, arresting cells in prophase.
- C.
A defect in the G1/S checkpoint prevents the pericycle cells from entering the synthetic phase, halting root primordia initiation.
- D.
Hyperactivity of the Anaphase Promoting Complex (APC) causes premature sister chromatid separation, leading to apoptosis of pericycle cells.
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
Auxin Polarity|Anaphase Promotion Complex (APC)|Pericycle activation
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Integrating Plant Anatomy (endogenous origin of lateral roots from the pericycle) with Cell Biology (APC's role in the M-phase checkpoint).
The trap relies on students failing to connect the cytological description ('chromosomes aligned at the equatorial plate') with the specific molecular machinery (APC) required to progress past that exact point, while simultaneously testing the anatomical location of lateral root initiation.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Plant Growth and Development - Class 11 |
| Concept | Auxin Polarity |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |