RNA-based catalyst.

Ribozymes play roles in normal cellular metabolism, are involved in the excision of introns from RNA , play important roles in translation, and arguably pre-dated enzymes in the .

ndeed, an important component the argument that an "" predated our present DNA and protein-based world is that ability of RNA to serve as catalysts (as a component of phenotype) that is in addition to the potential for RNA to carry genotype.