What came first - the ribosomal RNA or the ribosome?

Proteins being one of the fundamental biomolecules (like DNA and RNA), did evolve before ribosomes, which are complex biomolecular machines made up of RNA (2/3) and proteins (1/3). read more

It is a piece of RNA that forms a protein-like compound, and carries out biochemical functions. Basically, it is a piece of RNA that does double duty. The RNA World hypothesis holds that the first life was self-replicating ribozymes. At some point, these separated into two separate units - RNA which only contains information, and then something like a ribosome that translated that RNA to form proteins. read more