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Question #45252
The Question
In a dormant seed, the embryo cells are metabolically active but arrested in a quiescent stage (G0 phase). To break this dormancy and initiate seed germination, the cells must re-enter the active cell cycle (G0 to G1 transition). Which of the following represents the critical molecular switch that facilitates this transition?
Options
- A.
An increase in the ABA/GA ratio, which directly phosphorylates cell cycle arrest proteins.
- B.
Gibberellic acid-mediated degradation of DELLA repressor proteins, unblocking transcription factors.
- C.
Direct phosphorylation of the Rb protein by Abscisic acid, releasing E2F transcription factors.
- D.
Activation of translation by Abscisic acid, which overcomes the G1/S restriction point.
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
G0 Phase Quiescence|Seed Dormancy Breaking|Plant Growth and Development
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize 'GA breaks dormancy' but fail to understand the antagonistic ratio (GA/ABA) and the molecular mechanism of derepression (DELLA degradation).
The trap lies in confusing the direction of the hormone ratio and misattributing mammalian cell cycle regulators (Rb-E2F) directly to plant hormone pathways, even though they are functionally analogous in removing transcriptional blocks.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Cell Cycle and Cell Division - Class 11 |
| Concept | G0 Phase Quiescence |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |