Before You Begin
Question #45785
The Question
Cardiomyocytes often undergo natural polyploidization during development. However, if a localized aneuploidy occurs resulting in the overexpression of the Myosin Heavy Chain (MyHC) gene, which of the following represents the most accurate physiological consequence at the sarcomere level?
Options
- A.
The stoichiometric ratio of thick to thin filaments is disrupted, leading to defective structural assembly and hypertrophic cardiomyopathy.
- B.
The length of the A-band increases proportionally to accommodate the excess heavy meromyosin (HMM) during muscle contraction.
- C.
The ATPase activity of the myosin head is completely inhibited, preventing the formation of the cross-bridge with F-actin.
- D.
The excess MyHC binds to troponin-C, masking the active sites on the actin filaments and causing flaccid paralysis.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Evolutionary_Exception
Tackle problems where standard rules evolve or change based on specific environmental constraints.
Concepts Behind This Question
Actin|Myosin|Chromosomal_Theory_of_Inheritance|Aneuploidy
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Integrating 'Gene Dosage Effect' (Genetics) with 'Sarcomere Structure' (Locomotion).
Students often fail to realize that constitutive structural proteins require precise stoichiometric ratios dictated by chromosomal dosage.
Option B serves as a classic NCERT trap by suggesting the A-band length changes during contraction, which violates the Sliding Filament Theory.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Locomotion and Movement - Class 11 |
| Concept | Myofilament Protein Composition |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |