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Question #46468
The Question
Read the following statements regarding molecular evolution and the genetic code. Which of the following is INCORRECT?
Options
- A.
The degeneracy of the genetic code acts as an evolutionary buffer, permitting the steady accumulation of silent mutations.
- B.
The rate of a molecular clock is universally constant across all taxa because DNA polymerase proofreading fidelity is strictly conserved.
- C.
Without genetic code degeneracy, most point mutations would be non-synonymous, drastically altering the rate of neutral substitutions.
- D.
Silent mutations, which often occur at the third base of a codon, are the primary drivers of the molecular clock's 'ticking'.
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
DNA_Polymerase_Directionality|Phylogenetic_Trees
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often assume that because DNA replication is a fundamental, universal process, the mutation rate (and thus the molecular clock) is identical across all species.
This ignores the evolutionary divergence in DNA repair machinery, polymerase fidelity, and generation times.
The trap relies on the 'universally constant' absolute phrasing, testing the student's ability to synthesize molecular genetics with evolutionary constraints.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Evolution - Class 12 |
| Concept | Evolutionary Chronology |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |