Quantum Biology

Quantum mechanics has not only enabled postulation of new causes for biological processes that have been inexplicable any other way, but its mathematical precision provides the platform for ingenious experiments putting the imagery of its models to the test.  Most biochemistry within living cells occurs too rapidly to be accounted for with Newtonian concepts of force transfer by three dimensional contact between particles as in diffusion, even if the cytoskeleton arranges reaction pathways on the order of thousands.  Lightning fast mechanisms of the quantum scale have been proffered as key features of biology.  

Quantum theory is also suggestive for understanding consciousness, with alternate mechanisms potentially available to perception than those of solution chemistry.  Where no conclusive experiments have yet been constructed, what we do already know gives a good indication of what quantum effects can look like, their structure in natural environments and conditions which must be present for them to operate.

Up to this point, it has seemed that biochemistry at the quantum scale is exceedingly sensitive to incoming energy, so even the slightest increase in entropy can produce decoherence, converting a system into the more familiar form of self-contained, jostling particles combining and separating at rates determined by three dimensional structure.  Hypothesizing claims quantum biology is in need of a thermodynamic buffer shielding its actions from even most molecular-scale forces, which directs the search for its presence to specific components of even large macromolecules, particularly anywhere that individual protons, electrons or other charged particles are relatively free to shift across some kind of gap, such as between atoms.

An instance is the fast triplet reaction.  An electron in an outer atomic orbital paired with its partner of opposite spin is so to speak knocked or drawn out of position into another atom due to the orientation of these atoms to each other.  Even after this happens, the newly positioned electron remains quantum entangled with its former mate, while electromagnetic force is also exerted on it by its new partner, in which state it is in superposition putting it into a statistical percentage of same spin with each, a highly unstable formation that can be driven out of its wavering tension by tiny quantities of energy.  When this type of reaction exists upstream of biochemical pathways in key cells, its behavior might be magnified by molecular flow it instigates, engendering exquisite sensitivity of organic processes to the environment.

A fast triplet reaction was found by molecular biologists in cryptochrome, a pigment that is sensitive to blue light, present throughout the animal kingdom within many cell types and body parts, and was also identified in the eyes of European robins and antennae of monarch butterflies by collaboration with field biologists.  These two instances came to the attention of biochemists because it was apparent that the cryptochrome reaction is sensitive enough for responding to Earth’s magnetic field, a vanishingly small energy source, possibly constituting a perceptual mechanism of long-range migration.  Through a fortunate set of events the camps joined forces, discussing each other’s research projects and pinning down cryptochrome as a likely candidate for stimulating magnetically-induced qualia in transient species.  Cryptochrome and similar molecules in additional organs also have a plausible role for making organisms sensitive to the magnetic charge of storm fronts and other natural events, allowing them as everyone notices to find shelter far in advance.  Statistical math, conceptual modeling and chemistry experiments with a bioactive molecule have, along with ongoing fact-gathering about the natural world and interdisciplinary efforts, set modeling on course for mechanistic understanding down to the atomic level of a perceptual phenomenon previously untouched by science.

Enzyme activity has also been something of a mystery as its catalytic rates, hundreds of thousands of reactions per minute, seem beyond Newtonian physics.  Scientists hypothesized that quantum effects may be at work, and set out to uncover whether tunneling of protons or electrons at active sites might be in play.  A primary target of analysis was the hydrolysis reaction that breaks peptide bonds between amino acids, the building blocks of protein, inserting lysed water molecules into the former bonding site and stabilizing both monopeptides.  It was speculated that attractive and repulsive forces might induce near instantaneous motion of subatomic particles as peptide and water molecules split and form new chemical bonds, a sort of ricocheting flow of quantum wavicles towards and away from centers of charge, through whatever trace amount of solution occupies the catalytic space on this minuscule scale.  A fine theory, but a way to test it was required.

The quantum scale is of course tiny and so difficult to observe, but as has been stated it is also highly sensitive to surrounding energy as well as slight changes in atomic structure, and researchers utilized both of these properties in their search for tunneling.  Everyone knew that proteases, the peptide-lysing enzymes, function best at human body temperature, and reducing temperature slows the reaction at a measurable rate.  The degree of molecular agitation by heat is a significant variable, but if quantum tunneling is involved, a solution saturated with enzyme and substrate then chilled to very low temperature might result in a plateau of catalytic rate rather than continuous decrease as thermodynamic effects are rendered negligible and quantum effects continue unperturbed due to diffusion-transcending high concentrations.  Suppressing thermodynamic properties could perhaps unshroud the quantum process, and this is in fact what experimenting with super-cooled solution found, a rate plateau in a reaction laced with heat independence.

An experiment was also designed that exploited sensitivity of tunneling to particle size.  Batches of a protease’s substrate were prepared containing the hydrogen isotope deuterium in its peptide bonds, having one neutron in its nucleus as opposed to the nonneutron form almost exclusive to nature.  The hypothesis was that if tunneling of hydrogen wavicles was happening in the active site, rate of reaction would be slowed by a hydrogen nucleus roughly twice as massive because of its impaired ability to slip through interposing aqueous solution to adjacent atoms.  This chemical alteration yielded the result of a large drop in catalytic productivity, still more evidence that quantum tunneling is probably involved.  So far, experiments with enzymes have failed to rule out quantum effects and matched the predictions of quantum theory.  Though much remains to be learned about the flux in active sites, tunneling seems to be a key mechanism for cellular biochemistry, and hypotheses regarding metabolic pathways will be formulated with quantum mechanics in mind going forward.

One hundred percent efficiency in photosynthetic conversion of light energy to chemical bonding energy was another theoretical problem that researchers set out to solve, and once again quantum mechanics was at the forefront.  Chlorophyll pigments that capture UV light are found in abundance within plant surfaces, but the molecular receptacles for electron-absorbed energy, reaction centers where biochemical pathways are initiated that generate bond formation in molecules such as NADPH and glucose adapted for energy storage and transfer needs, are much less numerous and must service a multitude of chlorophyll molecules.  Newtonian mechanics predicts significant loss of energy in the form of light and heat as a statistically large portion of random movement by energized electron spheres misses its mark for energy transfer to other orbiting electrons in the transport chain, not proceeding in the right direction or finding the appropriate orientation at least some of the time.  However, energy of an excited electron in chlorophyll is harnessed by a reaction center every time – total energy  yield – regardless of proximities or other fluctuating conditions in a transport chain complex.  This exceeds by a large margin the performance of any energy transfer technology based on traditional mechanics, but quantum theory has led to devices such as superconductors with near photosynthetic efficiency, so it was pondered whether photosynthesis might be an ideal quantum system sculpted to virtual perfection by billions of years of evolutionary adaptation.  

Scientists know that electrons can exist as wavicles – spatially diffuse and capable of near instantaneous motion – when sheltered from thermodynamic entropy, so it was hypothesized that an electron wavicle in its spread out form might, because of structure peculiar to the cellular chemistry, take multiple routes to reaction center activation, perhaps overcoming random disalignment and decoherence as well as the Newtonian speed limit in some kind of tunneling.  As an amazing technological accomplishment, it became possible to stimulate the chlorophyll electrons of a single transport chain complex including only one reaction center with a laser and observe whether statistical signatures of quantum diffusion, wave particles flowing through multiple molecules to the reaction center, appeared.  The electronics are beyond most, requiring a highly technical understanding, but suffice it to say that this experiment did show mathematical signs of wavicle tunneling, which will perhaps help science enhance the efficiency of technology as we reverse engineer photosynthesis and learn to simulate it with assemblies of manufactured materials.

Quantum mechanics, in particular superposition, has also been invoked in one of its stranger applications, namely for hypothesizing the theory of evolution.  It has long been a quandary as to how the improbable leap from inorganic to organic chemistry transpired, especially the way in which self-replicating molecules emerged when they cannot even perform any functions at all without enzymes that simple intuition tells us they must have proceeded in time.  Looking at the relationship of DNA with crucial enzymes DNA polymerase and reverse transcriptase, it is hard to see how a symbiotic evolution through hundreds if not thousands of more primitive forms could occur.  We have not recreated it in a lab, as the basic ingredients simply do not yet come close to the refined machinery of actual life in our experiments.  The means of evolution have been quite alien to the evidentiary legacy of molecular genetics.  

What seemed chemically impossible a few decades ago became more tenable in the 21st century.  Researchers discovered that RNA, single-stranded replicators, are much more prone to mutation than DNA, as RNA polymerase does not proofread its genetic copying, so unprecedented enzymes are constantly being produced by new code in even modern cells, some of which can perform novel functions and change intracellular metabolism, at least temporarily.  This flexibility shortens the timeframe necessary for evolutionary transition.  Ribozymes have also been observed in the cytoplasm, hybrids of RNA strands and protein chains that catalyze some of their own functions.  These could be descendant molecules of a missing link: self-directing replicators.  It has become convincing to think of the living cell not as a factory or manufacturing plant with fixed, mechanical structure, but rather as a dynamic ecosystem in which its elements are semiautonomous, competing, coalescing into complex symbiosis, adapting to the nanoscale environment at rapid rates.

Even with the viability of an RNA and ribozyme ecosystem as the breeding ground for macroscopic life, the chances of thousands of types of symbiotic macromolecules each containing thousands of atoms arising in perfect sequence is astronomically small by conventional standards in solution chemistry.  A degree of functional order on that scale emerging from the inorganic environment would require a much longer duration than the entire 14 billion year history of our universe in the context of thermodynamically-driven diffusion along with energy transfer between basic particles of a roughly spherical nature and their chains and loops, let alone the less than 3 billion year incubation of prokaryotic life.  This led scientists to wrack their brains about what could accelerate rates of evolutionary formation.  

The tentative solution, still in its speculative stages, is the idea that protons and electrons in macromolecules can be in superposition with themselves as they undergo a kind of vibrational fluxing within and between atoms, existing in the form of overlapping wave phases as modeled by the Schrodinger equation, meaning that each molecule is in hundreds of different configurations at once, greatly reducing the time necessary to achieve an adaptive form.  The beginnings of replicator-generating evolution would be less competitive, with primitive macromolecules free to adopt a plethora of wave forms simultaneously, until in this blindingly fast tailoring of organic metabolism to the inorganic surroundings a real replicator or replicator/enzyme hybrid was born.  Expansion and diversification of replicator populations would exert additional forces of natural selection as more effective function self-propagated at higher rates, perhaps causing some of the replicators’ sites of quantum behavior, modelable as superposed wave functions, to collapse into forms providing greater reproductive fidelity, more subatomically stable, thermodynamic structures adapted for the inheritance of enduring traits, though pragmatisms of speedy reaction rate, magnified biochemical triggering and more complete energy transfer must have kept quantum effects in these molecules from entirely discomposing, a total decoherence.  Though life has not yet been created from nonlife in the lab, it may be the fastest and most inevitable step in evolutionary history, capable of happening in myriad ways.  Quantum mechanics makes it seem realistic that we will someday evolve the organic out of inorganic chemistry by artificial means, perhaps very soon.

Also in its initial stages is quantum theory’s promise for clarifying the workings of consciousness.  It has been known for decades that nerves function by voltage conductance down their length as ions are transported into the cell via a cascade of ion channels in the axon’s membrane, a sequence which ends by stimulating the release of neurotransmitters into synaptic clefts between axon terminals and dendrites as well as between dendrites, where neurons intersect.  A well-founded model, but as in the case of enzyme activity, this process happens too fast to be explained as discrete, spherical particles ferried through a three dimensional rate bottleneck.  It is also unclear how the qualia that comprise subjective experience can exist at all in association with traditional chemistry, resulting in a persistently advocated dichotomy of mind and matter within our modeling of the central nervous system.  

Accounts have ranged all the way from consciousness as a byproduct of brains, supervenient on matter and some kind of illusion, at most a certainty-bolstering epiphenomenon of perceived free will, to awareness as fundamental to the universe and matter nestled within it, the corporeal world essentially a perception.  Philosopher Rene Descartes proposed the pineal gland as the point of intersection between mental and material, physicist Roger Penrose offered that microtubules in cells might abet a mechanism of qualia production, but quantum biology presages a superior model, though tests are still forthcoming.

Those versed in quantum mechanics find it likely that rapid turnover in the ion flow cycle of nerve cells implies these ions take the form of a tunneling wavicle as they enter and leave through transport channels.  Rather than being seized as localized mass by some kind of membrane machinery and moved or coaxed with electromagnetic charge through a medium of three dimensions, they probably undergo higher dimensional, near instantaneous tunneling into and out of the cell, along with a complementary mechanism of wavicle afflux down longitudinal transport chains internal to the axon that bust through rate barriers of diffusion.  Along the length of an axon’s interior, transduction of the total signal via diffusion alone would require hours in some cases, yet comes to pass in milliseconds, so something much more potent is at work.  

In this quantum state, ionic motion may be acutely responsive to minute inputs of energy, just as in the fast triplet reaction, and the electromagnetic field of brains as registered by an EEG machine may be such an energy source.  If brain waves linked to states of awareness can in fact impact ion channels or other quantum-scale facets of the biochemistry of brain and nervous system, this may go a long way towards explaining how qualia seem both supervenient and causal, with subjective consciousness being describable and predictable in terms of energy field/quantum mechanical interactions.  Maybe we would gain the ability to say what something such as ‘color perception’ or ‘stream of consciousness’ is at the cellular level, and the dubious view that professes a paucity of function for the pervasiveness of qualia would be overcome.

Experiments have been performed showing statistically significant matching amongst the brain wave readings of meditators, just one instance of a wealth of evidence for quantum entanglement as a biological function that can trump thermodynamic decoherence.  These many observations befuddle even current quantum theory; a comprehension of the diverse conditions under which either entanglement or decoherence effects triumph is still to be devised, and we will hopefully be able to make inroads into the much contested arena of paranormality, determining what is and is not in fact illusion more decisively.

Mathematical measurements of an advanced kind provided us with models of matter and energy interrelatedness, its causal features, that had evaded theory until the 20th century, what we conceive as the quantum world, and crafty experiments based on these models promise to dramatically remake our knowledge of nature’s structure and our technology.  A wholesale transformation of the episteme is gaining steam that, if we can vouchsafe the continuity of scientific objectivity via strategic handling of institutions, may see humans safely into a new age of possibilities for humanist rationality.

A free download of the book Standards for Behavioral Commitments: Philosophy of Humanism, also available for preview below.  Topics covered include chemistry, biology, genetics, neuroscience, epistemology, the history of Western philosophy, cultural evolution, theory of cognition, ethics and much more.

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