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Question #45879
The Question
In an actively dividing cell culture, a highly specific inhibitor of DNA ligase is introduced during the S-phase. Which of the following accurately describes the immediate molecular consequence on the newly synthesized DNA?
Options
- A.
RNA primers remain attached to the 5' ends of Okazaki fragments, leading to the accumulation of RNA-DNA hybrids.
- B.
DNA Polymerase I fails to add deoxyribonucleotides into the gaps left by RNA primers, leaving single-stranded DNA stretches.
- C.
The 3'-OH and 5'-phosphate ends of adjacent DNA fragments fail to form phosphodiester linkages, accumulating single-strand nicks.
- D.
Continuous synthesis on the leading strand is completely arrested due to the inability to relieve topological strain.
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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
DNA Polymerase|DNA Ligase|RNA Primers
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Distinguishing between 'gap filling' (adding missing nucleotides, done by DNA Pol I) and 'nick sealing' (forming the final phosphodiester bond without adding nucleotides, done by DNA Ligase).
Students often conflate these two distinct steps of lagging strand maturation.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Molecular Basis of Inheritance - Class 12 |
| Concept | Okazaki Fragment Logic |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |