RNA's enzymatic properties are not sufficiently versatile for even the simplest imaginable proto-cell. The problem of the origin of information on the information carrying RNA remains unsolved. A proto-cell based solely on proteins is equally impossible, since proteins lack the ability to reproduce themselves. Each component of a living cell is breathtakingly complex, yet in isolation it cannot survive nor replicate itself. All the parts of the cell are necessary to its functioning and replication.
Nothing works until everything works.
This has been called irreducible complexity. Even small parts of the components of cells can be unimaginably complex. An example of this is the enzyme adenosine triphosphate synthase, found in all living cells including animals, plants, fungi and bacteria. The elucidation of the structure of ATP synthase won a 1997 Nobel Prize. Every cell contains hundreds of these miniature motors embedded in the surfaces of the mitochondria.