Which one is considered the first biological catalyst when life originated on earth ?

Options

A. RNA
B. DNA
C. Protein
D. Lipid

Answer

**Step-by-Step Text Solution:**

1. **Understanding Biological Catalysts**: Biological catalysts are substances that speed up chemical reactions in living organisms. The most common biological catalysts are enzymes, which are typically proteins.

2. **Identifying the First Biological Catalyst**: When life originated on Earth, the first biological catalysts were not proteins. Instead, research suggests that RNA molecules played a crucial role in early life forms.

3. **Role of RNA**: RNA is capable of both storing genetic information and catalyzing chemical reactions. Certain RNA molecules, known as ribozymes, can act as enzymes, facilitating biochemical reactions.

4. **Eliminating Other Options**:
- **DNA**: While DNA is essential for genetic information storage, it does not function as a catalyst.
- **Proteins**: Although proteins can act as enzymes, they are not considered the first biological catalysts because they evolved later.
- **Lipids**: Lipids are important for cell membranes but do not act as catalysts.

5. **Conclusion**: Based on the evidence, the first biological catalyst when life originated on Earth is RNA, specifically in the form of ribozymes.

**Final Answer**: RNA (specifically ribozymes) is considered the first biological catalyst when life originated on Earth.

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