What is the core proposition of the RNA world hypothesis regarding early life?

What is the core proposition of the RNA world hypothesis regarding early life?

• A. Life began with lipids
• B. Life used DNA for storage and catalysis
• C. Life used RNA for both information storage and catalysis
• D. Life began with proteins

Answer: (C)

RNA can carry genetic information and act as a catalyst, so it’s plausible that early life used RNA to store heredity and accelerate chemical reactions before DNA and proteins took over those roles. This dual capability is demonstrated by ribozymes, RNA molecules that catalyze reactions, showing that an RNA-based system could replicate and evolve. In today’s cells, RNA sits at the center of information flow (mRNA, tRNA, rRNA) and still participates in catalysis (the ribosome, for example, is largely RNA-based), which echoes how an RNA-first world could have operated. The other options miss this combination: lipids form membranes but don’t store information or catalyze reactions; DNA stores information but isn’t catalytic; proteins catalyze but don’t primarily store genetic information.

RNA can carry genetic information and act as a catalyst, so it’s plausible that early life used RNA to store heredity and accelerate chemical reactions before DNA and proteins took over those roles. This dual capability is demonstrated by ribozymes, RNA molecules that catalyze reactions, showing that an RNA-based system could replicate and evolve. In today’s cells, RNA sits at the center of information flow (mRNA, tRNA, rRNA) and still participates in catalysis (the ribosome, for example, is largely RNA-based), which echoes how an RNA-first world could have operated. The other options miss this combination: lipids form membranes but don’t store information or catalyze reactions; DNA stores information but isn’t catalytic; proteins catalyze but don’t primarily store genetic information.