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Question #47739
The Question
During the construction of a genomic library, a researcher digests whole human genomic DNA with a restriction endonuclease and subjects it to agarose gel electrophoresis. Instead of distinct bands, a continuous 'smear' is observed, making the precise elution of a specific single-copy target gene highly inefficient. Which of the following is the primary genomic reason for this phenomenon when compared to prokaryotic DNA manipulation?
Options
- A.
The human genome contains a vast amount of repetitive DNA sequences, generating millions of overlapping restriction fragments of varying sizes.
- B.
Eukaryotic DNA remains tightly bound to histone octamers during electrophoresis, causing irregular migration and smearing.
- C.
The presence of large introns within eukaryotic genes prevents restriction enzymes from making precise double-stranded cuts.
- D.
Eukaryotic DNA lacks palindromic recognition sequences, leading to random, non-specific cleavage by the restriction endonuclease.
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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
Downstream Processing|Ethidium Bromide Visualization|Bioreactor Geometry
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize 'elution' as simply cutting out a distinct band (as seen in plasmid digests) but fail to synthesize this with the structural reality of the eukaryotic genome.
The trap lies in confusing the theoretical action of restriction enzymes with the practical outcome of digesting a massive, repetitive genome, highlighting why isolating eukaryotic genes directly from a genomic digest is vastly more difficult than from a streamlined prokaryotic genome.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biotechnology : Principles and Processes - Class 12 |
| Concept | Ethidium Bromide Visualization |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |