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Question #46193
The Question
The long bones of Aves (e.g., Neophron) are pneumatic, an adaptation for flight. This hollow structure is achieved during skeletal development by preventing complete ossification of the medullary cavity. At the molecular level, this involves differential gene expression in osteoblasts. Which of the following epigenetic profiles would most likely be observed in the osteoblasts lining the developing medullary cavity of an avian long bone?
Options
- A.
High levels of heterochromatinization in the promoter regions of genes responsible for complete medullary ossification.
- B.
Maintenance of genes that inhibit bone matrix deposition in a densely packed, transcriptionally inactive state.
- C.
Complete dissociation of histone octamers from the DNA to allow continuous transcription of pneumatic factors.
- D.
Conversion of the entire osteoblast genome into euchromatin to maximize bone morphogenetic protein (BMP) signaling.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Comparative_Analysis
Sharpen your ability to evaluate multiple scenarios and distinguish between competing potential answers.
Concepts Behind This Question
Aves Pneumatic Bones|Chromatin Condensation States|Glandular Secretion Mechanism
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Bridging macroscopic evolutionary adaptations (pneumatic bones in Aves from Class 11 Animal Kingdom) with molecular genetics (Euchromatin vs Heterochromatin from Class 12 Molecular Basis of Inheritance).
Students often fail to apply the concept of differential gene silencing to specific anatomical developments, falling for traps that suggest absolute absence of histones or whole-genome euchromatinization.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Animal Kingdom - Class 11 |
| Concept | Aves Pneumatic Bones |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |