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Question #45860
The Question
A eukaryotic cell culture is subjected to severe thermal stress, exceeding its upper thermal tolerance limit. This results in the 'melting' of chromatin architecture and global transcriptional silencing. Regarding the biophysical basis of this nucleosome instability, which of the following statements is INCORRECT?
Options
- A.
A. Thermal denaturation of the histone octamer disrupts the electrostatic interactions between its basic amino acid residues and the DNA.
- B.
B. The loss of structural integrity in the H1 linker histone compromises the packaging of the 'beads-on-a-string' structure into the 30 nm solenoid.
- C.
C. The extreme heat cleaves the covalent phosphodiester bonds of the DNA backbone, permanently preventing transcription factors from binding.
- D.
D. The destabilization of the protein-DNA complex alters the spatial availability of promoter regions, effectively blocking sequence-specific access.
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
Histone_Octamer|H1_Linker|Thermal_Tolerance_Ranges
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Distinguishing between covalent and non-covalent bond stability under thermal stress.
Students often associate 'DNA melting' (as seen in PCR) with the destruction of the DNA strand itself, failing to realize that thermal melting only breaks the hydrogen bonds between base pairs and the electrostatic interactions in nucleosomes, while the covalent phosphodiester backbone remains intact.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Molecular Basis of Inheritance - Class 12 |
| Concept | Histone Octamer Charge Interaction |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |