Before You Begin
Question #46129
The Question
Obelia exhibits metagenesis, where the sessile polyp transitions into the free-swimming medusa. Both morphological forms possess identical double-stranded DNA that strictly obeys Chargaff's rule. A researcher introduces a novel chemical inhibitor that specifically blocks the transcription of regulatory RNAs from the non-coding DNA strand in a polyp, resulting in its complete inability to form medusae. Which of the following statements is INCORRECT regarding the genetic and reproductive principles of this phenomenon?
Options
- A.
The structural polymorphism seen in Obelia is a result of differential gene expression, confirming that metagenesis does not involve a change in the underlying genotype.
- B.
The chemical inhibitor disrupts the epigenetic switching and non-coding strand utility necessary for the morphological transition from polyp to medusa.
- C.
Chargaff's rule of base equivalence explains the structural stability of the DNA in both forms, but is inadequate to explain their phenotypic polymorphism.
- D.
The inhibitor halts metagenesis by preventing the meiotic division required for the polyp to produce the haploid medusa generation.
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
Cnidarian Polymorphism|Non-Coding Strand Utility|Chargaff’s Rule Limitation
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students frequently confuse animal metagenesis with plant alternation of generations.
In plants, a diploid sporophyte undergoes meiosis to produce a haploid gametophyte.
In Obelia, BOTH the polyp and medusa are diploid.
The trap relies on the false assumption that the medusa is haploid because it eventually produces gametes, and that the transition requires meiosis.
Additionally, the question synthesizes Animal Kingdom (Metagenesis) with Molecular Basis of Inheritance (Gene expression vs.
Chargaff's rule).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Animal Kingdom - Class 11 |
| Concept | Cnidarian Polymorphism |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |