In 1971, Dr. Blobel and a colleague, Dr. David D. Sabatini, who later headed cell biology studies at the New York University School of Medicine, proposed a bold idea known as the “signal hypothesis.” It suggested that each protein carries in its structure a sequence of signals comparable to address tags on airport luggage or ZIP codes on mail to ensure that it all arrives safely.
The signals, Dr. Blobel found, are chains of amino acids created by protein-making machines that read distinctive RNA codes and then fix them on each new batch.
Like transmitters, these signals order receptors in membranes to open up watery holes so that proteins can pass through. They then act as GPS devices to cross the crowded terrain of a cell or a human body and, like finding a mailbox across the universe, penetrate precisely the right worksite organelle for each protein’s assigned task.
Proteins have many tasks: rebuilding or replacing constantly dying cells, protecting against viruses and bacteria, regulating body chemistry, reading DNA to make new molecules, releasing hormones to signal and repair tissues and organs, carrying and binding atoms throughout the body, and many other functions.
From the New York Times obituary, 2/20/2018, for Gunter Blobel
The point this statement makes is that biology is different from physics. Proteins are molecules, but in organisms they act as if they can think, while inorganic molecules do not. This is how organic evolution is different from mechanistic physics.