Bovine biology series
Part - 47 Life cycle (8/8)
We have arrived at the end of the journey. At least for a biology journey, and thus in this 47th article, we finish. Throughout the four years we have reduced the complex into the simple, and yet we have just scratched the surface. For reductionism is never done, nor is it ever fully explained.
In solving the riddle of life, as "where did we come from, what are we made of, and what is to become of us?" are unanswerable. And even though there are those proclaiming they truly know, we know inwardly that the very most we can do is participate in life, and recognize that the journey of life is more glorious and magnificent than we can ever describe. That is what poets do, you know.
We have recently taken the simple and built the complexity that defines life. We begin, of course, with atoms. At the basis of this beginning is carbon, an atom consisting of six protons and six electrons. What is remarkable about carbon is that it has two electrons in its first orbital shell and four in its second. Now the second orbital shell becomes filled when it contains eight electrons, thus with a carbon atom, there is room for four more electrons to join with the four already there.
Hydrogen, for instance, has one electron. Thus in creating methane, or CH4, four atoms of hydrogen join with a single carbon atom and the molecule is made stable.
The substance of life is thus made, in that orbital electron shells are filled creating a stable molecule. This means, of course, that there is a longing for atoms to combine, and this attraction for each other is called a valence. The valence for carbon is four.
Oxygen has a valence of two, because it owns eight electrons, six of which are on the second orbital shell. The highly favorable attraction of an oxygen atom and two hydrogen atoms is so strong that whole oceans are made. And we know that H2O is a stable molecule.
A third example of atomic combination is silicon, an atom with 14 electrons, four of which reside in its third orbital, and this orbital longs for four more electron to fills its valence. And so it combines with two atoms of oxygen, with six electrons in its second orbital shell (and therefore searching for multiples of two electrons to combine with), and the very stable molecule silicate, SiO2, is made. Silicate (sand, silt) is the most abundant molecule found in the earth’s crust.
We know, however, that if all atoms joined together just to fill out their own valence attractions, soon such stability would exist that the world might consist only of methane, water and silicate, for instance.
But that is not the case. Indeed, what is remarkable about atoms is that even though they long to satisfy a valence attraction, sometimes the valence is left open-ended. That is, atoms combining with atoms may do so with certain electrical combinations, opposing charges attracting, yes, but it means that carbons can join with other carbons and they can adhere to other hydrogen’s, nitrogen’s, sulfur, phosphorus, and so on, in such a manner that as molecules become more complex, they become larger and capable of greater complexity. And the process is never ending. Because the complexity of a molecule is constantly changing, the longing for electron valence is enduring as well. The electrical charges now are secondary, for the transactions of atoms with molecules become metabolism.
This, then, is why entropy, that second law of thermodynamics that states all systems are running downhill towards chaos, is met by atomic valence and the building of molecules. But let us not forget that what drives this is the fuel source of hydrogen burning in a yellow star 93 million miles away, our sun, erupting photons that reach the earth’s surface. The oceans and the land are bathed in the radiant energy of the sun, fighting the law of entropy.
And life, then, is atoms making molecules and molecules making metabolism, in which molecules are made, stored (anabolism) and then broken down and used via metabolic pathways creating smaller molecules and eventually atoms once more (catabolism). Life is a circle, where life is derived from life, but only when some part of life is consumed, or dies.
Yet this is structuralism and reductionism combined, and I may liken this accounting of electrons and electric charges to number counting, that determinism of exact mathematical answers. The answer is not here in this approach.
We biologist’s wonder, don’t we, that at what point (if we may call it that), is the flicker of life defined as more than just the summary collection of atoms and molecules and cells? Surely we ponder the dream, an inward one for me, that life is so beautiful that it is inevitable. That wherefore stardust may be our origins, of some hydrogen star bursting forth with the elements of life as found in the periodic table of elements, we were destined to be made from these atomismal bits and pieces from afar and yet so near.
We long to be, I think, recognized as part of some magnificent creation of that which we see beneath our microscopes and through the eyes of a giant mirror gaining access to light have been sent over ten to fifteen billions light years. We long to be derived from what once was darkness and now is bathed in light; entropy held at bay, we are supposed to be here.
The study is both outward and inward. In our search for answers, we find them merely presented to us after longingly searching for them, and once found, they are inadequate, for indeed, the answers cannot be found.
For as one may know who has in the middle of the night held in our hands the newly born calf, a sum of eighty pounds of flesh that just 280 days before was the simple gamete, the longingly active sperm cell swimming in salty froth until alas, the beauty of an ovum came forward, longingly beautiful itself, and they joined. Who amongst us can doubt that there is more to this 280 day journey than just electrons finding attractive parity in valence orbits, that atoms find their own electrical charge fulfilled, that molecules form in fluid of inorganic salt, that cells are formed, tissues arise, organ differentiation is made, and oxygen enters a sac of tissue while carbon dioxide is repelled into motherly blood flow?
Who amongst us can elicit nothing but awe in the face of evening star visits, when overhead the celestial dance is underway, a shooting star streaks nearby, and the lunar light longs to fill our horizon with glorious illuminations?
Who amongst us can truly stay away from the wonder of a microscope as our eyes fill the glass and we watch a dozen bacteria swim in water, longingly beautiful themselves; they are organic and they are owners of the same DNA nucleotides as you and me, those A, T, G, and C molecular symbols from which our, and their genotype is defined?
And who can wonder why every cell in every plant and animal that has lived and lives today is comprised of largely the same fifty atoms; the difference among them one of relative combination rather than atomic definition?
At the conclusion, then, I am confident in my statement that any discovery of science is met by the same discovery of that which cannot be defined by science; rather it is defined by art expressed as interpretations of what we cannot measure or quantify or determine fully.
Wherefore this biology study has scratched the surface of life, in the words contained are meanings that only the reader can define, make use of, and therefore make the darkness of ignorance come alive with light.
Indeed, in a month or year or decade we may find something else in our telescopes and microscopes that alters our view, changes our mind, and redefines our thoughts. We are explorers, still…..
In my final biology series article, part 48, a literature source will be provided. And that will be all.
|