Yes, specifying which proteins are made, and how much of each and how that varies with cell type is most of what determines an organism's phenotype. This is lar

Yes, specifying which proteins are made, and how much of each and how that varies with cell type is most of what determines an organism's phenotype. This is largely because enzymes are proteins, and enzymes control all the biochemical reactions in a cell. But proteins can also be transcription factors, which control which other proteins are produced, and they can be important for their mechanical properties, etc. So, not some boring category of biomolecule that gets listed on nutritional information section on food packaging.