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Question #47706
The Question
A researcher treats a bacterial DNA fragment containing a complete transcription unit with a restriction endonuclease. The enzyme makes a double-stranded cut exactly within the promoter region, leaving the entire structural gene and terminator sequences completely intact downstream. If this modified DNA fragment is introduced into a suitable bacterial host, which of the following will be the immediate consequence?
Options
- A.
Transcription will occur normally because the 3' → 5' template strand of the structural gene remains intact.
- B.
Transcription fails completely as the RNA polymerase holoenzyme cannot recognize and bind to the disrupted promoter sequence.
- C.
RNA polymerase will bind directly to the intact structural gene, but the resulting mRNA will lack a 5' untranslated region (UTR).
- D.
Transcription initiates normally but halts immediately at the cleavage site, producing a truncated, non-functional RNA transcript.
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 | Ori Sequence | Vector Compatibility
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often confuse the integrity of the 'coding sequence' (structural gene) with the 'expression capability' of the gene.
A common misconception is that if the template strand for the actual protein is intact, transcription can somehow proceed.
The trap tests the absolute prerequisite of the promoter sequence for RNA Polymerase holoenzyme binding (initiation) versus the elongation phase.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biotechnology : Principles and Processes - Class 12 |
| Concept | Restriction Endonuclease Nomenclature |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |