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Question #47733
The Question
During DNA fingerprinting, Variable Number of Tandem Repeats (VNTRs) are separated via agarose gel electrophoresis and visualized. Regarding the molecular mechanism of the staining agent used in this process, which of the following statements is INCORRECT?
Options
- A.
Ethidium bromide imparts a bright orange fluorescence under UV light by intercalating between the stacked nitrogenous bases of the DNA helix.
- B.
Insufficient concentration of the stain will mask the presence of genetic polymorphisms by failing to adequately tag the separated VNTR fragments.
- C.
The distinct spatial banding profiles of VNTRs are visualized because the stain covalently binds to the negatively charged phosphodiester backbone of the satellite DNA.
- D.
Even after successful staining with ethidium bromide, the separated satellite DNA fragments remain completely invisible to the naked eye under standard visible light.
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
Restriction_Endonuclease|DNA_Fragment|Agarose_Matrix
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize that 'Ethidium Bromide stains DNA' but fail to grasp the exact molecular mechanism (intercalation between base pairs vs. binding to the backbone) and the nature of the bond (non-covalent vs. covalent).
The trap leverages 'Functional Confusion' by mixing the cause of the banding pattern (size separation of VNTRs) with a fabricated sequence-specific, covalent staining mechanism.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biotechnology : Principles and Processes - Class 12 |
| Concept | Gel Electrophoresis Migration |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |