During the course of origin of life what was the sequence of substances which appeared on earth:

Options

A. Water, oxygen, nucleic acid, enzymes
B. Amino acids, ammonia, phosphates, nucleic acid
C. Glucose, amino acid, nucleic acids, proteins
D. Ammonia, Amino acids, proteins, nucleic acids

Answer

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

1. **Early Earth Conditions**: The early Earth had a very thin atmosphere, primarily composed of gases like hydrogen, nitrogen, and carbon, with very little oxygen. The high temperatures were due to volcanic activity and lightning.

2. **Formation of Simple Compounds**: As the Earth cooled down, the energy from lightning contributed to the formation of simple compounds such as ammonia (NH3), methane (CH4), and cyanides.

3. **Rainfall and Ocean Formation**: The cooling of the Earth led to rainfall, which caused these simple compounds to mix with water, creating a primordial soup in the oceans.

4. **Formation of Amino Acids**: In this primordial soup, the combination of water and the simple compounds facilitated the formation of amino acids, which are the building blocks of proteins.

5. **Formation of Proteins**: With the presence of amino acids, proteins began to form, which are essential for various biological functions.

6. **Emergence of Genetic Material**: The first genetic material to appear was RNA (ribonucleic acid). RNA served dual roles as both genetic material and a catalyst for protein synthesis.

7. **Development of Early Organisms**: The presence of RNA, amino acids, and proteins allowed for the emergence of the first organisms, which were chemoheterotrophic anaerobes. These organisms thrived in an oxygen-poor environment.

8. **Evolution of Life Forms**: Over time, these early organisms evolved, leading to the development of oxygen-consuming autotrophs and heterotrophs as the oxygen levels in the atmosphere increased.

9. **Sequence of Substances**: Thus, the sequence of substances that appeared on Earth during the origin of life is:
- Ammonia (NH3)
- Amino Acids
- Proteins
- Nucleic Acids (RNA)

**Final Answer**: The sequence of substances that appeared on Earth during the origin of life is: Ammonia → Amino Acids → Proteins → Nucleic Acids (RNA).

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