"The cellular genetic system is composed of several mutually dependent subsystems.
Single and double arrows represent an immediate, direct dependency for a particular subsystem to function.
Dozens of protein-based molecular machines are indispensable such as DNA and RNA polymerases; topoisomerases; helicases (for nucleotide, amino acid and cell membrane synthesis); transcription factors; error correcting enzymes; aminoacyl tRNA synthetases, etc." CMI