Molecular Mind in Cellular Motors 1: Chemical Bonds for Agile, Ingenious, Perceptive, Resourceful Behavior.

Most people picture molecules as rigid, locked-together structures — like tiny pieces of stone. But the molecules inside every living cell are something far more remarkable: they hold together loosely and temporarily on purpose.

The strongest molecular bonds—called covalent bonds—share electrons so firmly that breaking them requires a serious chemical event. These strong bonds produce the stable structures of large molecules like DNA, RNA, lipids, and proteins. When the DNA/RNA/Protein dogma was first described, excitement about information embedded in covalent structures influenced  biological research for many decades. Almost all scientific research was focused on how information was stored and used in these large somewhat static molecules

It was believed that the way biology worked was based largely on these fairly permanent covalent bonds in information scaffolds of DNA and proteins. Most work was on protein structure because the state of molecular imaging largely allowed scientists to decipher the amino acid sequences of proteins, rather than considering the actions of non-covlent bonds. RNA was considered to be secondary, just a copy of DNA on the way to a protein.  

But life also depends on something subtler—that is, weak, non-covalent bonds—that form and dissolve constantly, trillions of times per second throughout every cell in your body and every molecule in each cell. Non-covalent bonds produce most actions in and around the large macromolecules. 

These weak bonds — called hydrogen bonds, electrostatic attractions, transient dipoles, and the clustering of water-avoiding regions — allow molecules to approach each other, grip briefly, do something, and let go. Without this capacity for temporary connection, cells would be too rigid to breathe, move, or respond to the world. These rapid, flexible, transient bonds are what allow biological action to proceed at the time scales needed for perceptions, analysis, and strategic responses. The time scales of life are measured in attoseconds (or 10 to the minus 18 orders of magnitude) for electronic motion in atoms, molecules, and solids; and femtoseconds, (or 10 to minus 15 orders of magnitude) for the speed of chemical, molecular dynamics. These are the speeds that life requires, only possible with non-covalent bonds.

Recently other factors have been discovered that contribute to the incredibly dynamic, rapid, variable actions of biomolecules that take advantage of non-covalent bonds. It has been found that most proteins are not static, but have some strands of amino acids that constantly move in unbelievably complex and rapid motions. Also, with the recent ability to image the structures and actions of RNA, it has been found that RNA strands are also often in motion, forming vastly complex configurations, in fantastically rapid time scales.

The great biochemist Linus Pauling, winner of two Nobel Prizes, predicted this a century ago. He said that weak bonds would turn out to be the secret engine of living things. He was right. Life is not made of inert stone. Genetic information engraved in vital cellular structures must be maintained in covalent bonds, but even with these huge molecules, all the actions that are needed for this information to function are produced with extremely complex, almost instantaneous non covalent bonds.

Life is more like a flowing, self-organizing conversation between molecules — held together not by force, but by the right kind of attraction, at the right moment, in the right place.

These infinitely subtle, complex, ever changing non-covalent bonds instantaneously respond in every molecule, in all parts of every cell, in all aspects of life with responsive, adaptive, resourceful actions.

How can these bonds not be enabling mind in nature?

In this series of posts, we will follow that conversation—from molecular bonds, water molecules filling every cell, rapidly moving molecular strands—all the way to molecular machines that walk upright like humans, make decisions, converse, and deliver cargo across the vast interior landscape of a living cell.