The idea that when life originated on Earth a macromolecule

The idea that, when life originated on Earth, a macromolecule other than DNA served the role of information storage and that this same macromolecule carried out catalysis is called the _____ hypothesis.

1) macromolecular world

2) water world

3) carbon world

4) RNA world

Solution

4) RNA world

In 1986, the RNA World Hypothesis was proposed by Walter Gilbert, on the possibility of RNA self-replication.

However, the ability of the RNA molecules to catalyze the synthesis of another identical RNA is questioned. Many of the ribozymes can catalyze either the formation or breakup of phosphodiester bonds. In prokaryotes, the 23S and in eukaryotes, the 28S large subunits of rRNA are ribozymes, which catalyze the formation of peptide bonds.

Many of the naturally occurring ribozymes can catalyze only one reaction, for example the self-splicing introns. The properties these ribozymes are far away from the expectations of RNA World Hypothesis. Perhaps, the self-replicating RNA was existed during the times of evolution but was replaced by the more stable DNA molecules.