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Question #46427
The Question
The Miller-Urey experiment successfully demonstrated the abiotic synthesis of amino acids under primitive Earth conditions. However, the subsequent progression of chemical evolution—the polymerization of these monomers into complex macromolecules—faced a critical thermodynamic bottleneck in the primordial oceans. Which of the following accurately identifies this bottleneck and a plausible mechanism to overcome it?
Options
- A.
Bottleneck: High temperatures caused rapid oxidation of monomers. Mechanism: The reducing atmosphere provided a protective shield against degradation.
- B.
Bottleneck: Condensation polymerization is thermodynamically unfavorable in an aqueous medium due to the dominance of hydrolysis. Mechanism: Adsorption of monomers onto reactive clay surfaces or concentration in evaporating tidal pools.
- C.
Bottleneck: The absence of biological enzymes made peptide bond formation impossible. Mechanism: Ribozymes spontaneously formed from methane and ammonia to catalyze the reactions.
- D.
Bottleneck: Continuous lightning strikes cleaved the newly formed peptide bonds. Mechanism: The formation of the ozone layer shielded the primordial soup from electrical discharges.
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
Spark_Discharge|Abiotic_Synthesis|Temperature_Moisture_Lignin
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often assume that the primordial soup naturally facilitated polymerization just as it did monomer synthesis.
They fail to recognize the thermodynamic conflict between condensation reactions (which produce water) and an aqueous environment (which drives hydrolysis).
The trap lies in confusing the conditions required for monomer synthesis (reducing atmosphere, lightning) with the distinct micro-environmental conditions required for polymer stability (removal of water/adsorption).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Evolution - Class 12 |
| Concept | Miller-Urey Conditions |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |