I wouldn't call amino acids "large complex basic units" at all, they may be bigger than an atom but 10-20 heavy atoms is hardly complex. Plus many amino acids t

I wouldn't call amino acids "large complex basic units" at all, they may be bigger than an atom but 10-20 heavy atoms is hardly complex. Plus many amino acids themselves are synthesized in vivo. Moreover, this misses the point somewhat, namely that the resulting peptide chain folds into a protein with essentially atomically precision. Atoms may not be placed one by one, but an atomically precise structure is created.