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Question #45345
The Question
In a transgenic dicot plant, RNA interference (RNAi) is utilized to silence the genes essential for the transition of the zygotic embryo from the globular to the heart-shaped stage. This developmental arrest triggers the surrounding nucellar cells to divide, protrude into the embryo sac, and form multiple embryos. Which of the following statements regarding this phenomenon is INCORRECT?
Options
- A.
The multiple embryos formed from the nucellus are diploid and represent a form of apomixis known as adventive polyembryony.
- B.
The RNAi mechanism achieves gene silencing by preventing the transcription of the specific genes responsible for the globular-to-heart transition.
- C.
The source of the complementary RNA required for this RNAi process could be mobile genetic elements (transposons) that replicate via an RNA intermediate.
- D.
Despite the arrest of the zygotic embryo, the triploid primary endosperm nucleus (PEN) is still essential to provide nourishment to the developing nucellar embryos.
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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
Pro-embryo|Suspensor|Silencing_RNAs
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: The exact mechanism of RNA interference (RNAi).
Students frequently confuse 'gene silencing' with the inhibition of transcription (DNA to mRNA).
RNAi specifically acts post-transcriptionally by degrading or blocking the translation of mRNA.
This question also tests cross-chapter synthesis, combining Plant Embryogeny/Polyembryony (Chapter 2) with Biotechnology Applications (Chapter 12).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Sexual Reproduction in Flowering Plants - Class 12 |
| Concept | Polyembryony Mechanisms |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |