June 14, 2019
Life Can't Make It Without Them
Brazilian scientist Marcos D. Eberlin has written a book, Foresight: How the Chemistry of Life Reveals Planning and Purpose (Discovery Institute Press). The book is adding another level to my understanding of what makes life work. Consider just the exterior of the living cell, the membrane.
The relationship of a living cell to oxygen and water is a matter of life or death, so the makeup of the membrane is crucial.
The oxygen molecule is ... essential to life; but only a life form that can efficiently trap and transport the devil O2 exactly to the place where it can be used as an energy source would benefit from its angel side. Otherwise, O2 becomes life's greatest enemy.
Rupture the membrane of a living cell, exposing it to the air, and you will see the great damage O2 and a myriad of other chemical invaders can do to a perforated cell. Death would be swift and sure.
The first membrane on earth could not be "simple." It's a lot more than plastic wrap. A cellular membrane that functions as a shield also must allow penetration of nutrients inside and the passage of cellular waste outside--while keeping out other substances. Selective "smart" channels had to be in place from the beginning. A double-layer membrane was needed, one that would promptly and efficiently protect the cell from the devastating O2 permeation, remain stable in aqueous acid media, and ably handle fluctuations in temperature and pH. To do all these tasks, the cell's molecular shield also would need a mechanism to sense changes in temperature and pH, and react accordingly, adjusting the membrane's chemical composition to handle these physical and chemical changes.
The membrane also contains phospholipids, which are complex biomolecules that have heads and tails:
The head is polar and water-loving (hydrophilic), while the tail is non-polar and water-hating (hydrophobic). This dichotomy of "tastes" is crucial, because it allows for a marvelous trick: In the presence of water, the biomolecules automatically arrange themselves so as to form round, double-layer structures with all the polar heads lining up next to each other and the elongated tails packed very tight.
Attracted by finely-tuned chemical forces, two such monolayers come together so that the tails from both layers will also contact each other in a tail-to-tail arrangement.
In water, the tails are hidden while the water-loving heads on the outside and inside of the cell are exposed to water. Voilà! There is much more detail about other aspects of the membrane, including the electrical part of the cell and its membrane. All these are crucial components of a (not-so) "simple" living cell.
Life exists because it has boundaries. Chemicals have fixed (not fluid) properties. These properties allow life to have the flexibility to respond to different environments. These living adaptive responses become explainable after we study them closely and figure out the principles and patterns at work.
Adaptations occur following certain laws and patterns that we have been slowly discovering. The work of biochemical scientists is to figure out the thousands of interactions that make life as we know it possible. In discovering how things work, data is mapped onto hypotheses to look for convergences and patterns.
Our bodies are full of boundaries and depend on fixed physical laws to adapt as needed. There are 200 different kinds of cells, with 20 different types within each kind. Consider just the eye, optic nerves, neurons, nerve cells, muscles, heart cells with their proper electrical charges. They must function in minute three-dimensional detail, plus a fourth: timing.
My body as a unit also has limits and boundaries: I must have the right amount of water, air, and nutrients. What goes into my body must be controlled and regulated if life is to continue. If I do this right, I can live and adapt as needed.
This boundary rule of control and regulation is true for life: for a cell, a body, a mind, a family, a village, a nation, a culture. A church. Boundaries are there for all living things. Rupture them and death will follow. Set rules and functions serve the good of all, enabling survival even when the environment changes. And, boy, has it.
Yours for Christ, Creed & Culture,
James M. Kushiner
Executive Director, The Fellowship of St. James
James M. Kushiner is Executive Editor of Touchstone: A Journal of Mere Christianity, and Executive Director of The Fellowship of St. James.