Which sequence of events best describes the current theory of the origin of life on Earth?

• A. Formation of DNA → Appearance of multicellular organisms → Abiotic synthesis of organic molecules → Evolution of protocells
• B. Development of self-replicating molecules → Abiotic synthesis of organic molecules → Formation of protocells → Evolution of cellular life
• C. Evolution of cellular life → Formation of protocells → Abiotic synthesis of organic molecules → Development of self-replicating molecules
• D. Abiotic synthesis of organic molecules → Formation of protocells → Development of self-replicating molecules → Evolution of cellular life

Answer: (D)

Verified step by step guidance

1. Understand the concept of abiotic synthesis: Abiotic synthesis refers to the formation of organic molecules, such as amino acids and nucleotides, from inorganic precursors without the involvement of living organisms. This is considered the first step in the origin of life as it provides the building blocks necessary for life.
2. Learn about protocells: Protocells are simple, membrane-bound structures that can encapsulate organic molecules. They are thought to have formed from the aggregation of organic molecules and represent a precursor to true cellular life. This step follows abiotic synthesis as protocells provide a structure for chemical reactions and molecular organization.
3. Explore the development of self-replicating molecules: Self-replicating molecules, such as RNA, are crucial for the origin of life because they enable the transmission of genetic information and the ability to reproduce. This step comes after protocells, as the environment within protocells could support the emergence of self-replicating molecules.
4. Understand the evolution of cellular life: Cellular life evolved from protocells and self-replicating molecules. This step involves the development of more complex structures, metabolic pathways, and the ability to sustain life processes independently. It marks the transition from simple protocells to fully functional cells.
5. Review the sequence: The correct sequence of events in the current theory of the origin of life is: Abiotic synthesis of organic molecules → Formation of protocells → Development of self-replicating molecules → Evolution of cellular life. This sequence reflects the logical progression from simple chemical processes to complex biological systems.