Why in the News?
A recent study published in the Nature suggests that simple molecules called aminoacyl-thiols may have helped amino acids stick to RNA (ribonucleic acid) without enzymes, giving clues to how protein-making began on early Earth.
About the RNA–Amino Acid Link:
- Discovery: Study showed that aminoacyl-thiols (simple prebiotic molecules) can attach amino acids to RNA directly (aminoacylation) without enzymes.
- Modern Parallel: In cells today, this is done by aminoacyl-tRNA synthetases before ribosomes build proteins. This created the “chicken-and-egg problem”: proteins are needed to make proteins.
- Chemical Mechanism:
- Thioesters: Enable amino acids to attach to RNA (“charging RNA”).
- Thioacids: Enable amino acids to link into peptides.
- Robustness: Works at neutral pH, across many amino acids, with unexpected selectivity for RNA despite other molecules being more reactive.
Significance for Origin of Life:
- RNA World Hypothesis: Supports the idea that RNA and amino acids interacted directly before enzymes evolved.
- Chemical Advantage: Shows RNA had a natural edge in early Earth conditions, explaining its central role in life’s origin.
- Prebiotic Plausibility: Aminoacyl-thiols could form from simple nitriles and thiols, and reactions occurred even in cold/frozen pools resembling early Earth.
- Evolutionary Pathway: Suggests life began with short peptides, with RNA later evolving control, leading to coded protein synthesis and ribosomes.
| [UPSC 2022] Consider the following statements : DNA Barcoding can be a tool to:
1. assess the age of a plant or animal. 2. distinguish among species that look alike. 3. identify undesirable animal or plant materials in processed foods. Which of the statements given above is/are correct ? Options: (a) 1 only (b) 3 only (c) 1 and 2 (d) 2 and 3* |
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