Quantum Biology [Quantum Explora 2022]

Quantum science is about the very basic building blocks of nature and deals with energy and matter at the smallest level. It has influenced many fields of science by explaining concepts previously deemed unexplainable by classical science. However, the more exciting relationships are usually more commonplace, such as how quantum science ties into biology, which focuses on life itself.

Often, there are biological phenomena that cannot be explained by classical physics, sparking the need for a new area of quantum science, namely quantum biology, to develop in order to utilize quantum mechanics and quantum-related concepts to explain biology. A large concept in biology is what genetic mutations are and how they come to be. In order to help explain genetic mutation, ideas from quantum mechanics can be used. Genetic mutations are phenomena that, in short, are changes to a gene's DNA sequence, which can either barely affect the organism at all or leave the organism with new traits. These traits can either be helpful or harmful to the organism and to its survival.

One-way classical physics attempts to explain these mutations is by citing a process known as “point mutation”: when a single base pair is added to, deleted from, or changed in a genome. Base pairs are two nucleotides, or nitrogen-rich bases, that go together to create DNA’s structure, and include adenine, cytosine, guanine, and thymine, where the normal pairings are adenine to thymine and cytosine to guanine. Point mutation reasons that there are multiple different types of point mutations that can occur in DNA, and each one involves different variations of insertion and deletion of bases from the genome. However, classical physics mostly fails to explain precisely why point mutation occurs in the first place because the classical proton transfer theory and classical thermodynamics fail to consider all of the instances where protons move around in DNA. This is where quantum mechanics comes into play, suggesting that “proton tunneling”, a phenomenon in quantum where a proton disappears in one area and appears at a nearby location, causes protons in the hydrogen bridges of DNA to move around. This can slightly alter the hydrogen bonds of DNA, which can lead to mistakes when DNA replicates itself. These errors can end up causing the normal base pairings of adenine to thymine and guanine to cytosine to switch around, which can change information of traits and therefore cause mutations.

This is because DNA “unzips” when breaking the bonds between the base pairs using an enzyme called polymerase when it attempts to replicate itself. New bases are then placed into the open slots left by the broken bonds. However, when polymerase finds a proton in an unstable or incorrect position, it can end up attempting to match the wrong base pair with the already attached base. This shows how the quantum idea of proton tunneling helps explain point mutation because the displaced proton causes the polymerase enzyme to become confused and “change” base pairs in the genome, which helps explain one of the effects of point mutation.

However, in the bigger world, such a theory would not work at all because definitive information on a large moving object’s speed and location can easily be found. In other words, an object like a ball cannot simply appear in a front yard, disappear, and reappear on a road. Because of this, this theory relies on the quantum principle of uncertainty in order to be plausible. This principle shows that the location and speed of very small particles cannot be calculated exactly, and instead, calculating the probability that one would appear in a certain spot given its rate of travel is a more accurate way of finding the general position of a particle. This principle can be used to calculate the probability of a proton tunneling from a certain area to a certain area in the hydrogen bonds of DNA in the same way.

How can this quantum-based explanation of a common biological concept be applied in real life? Well, as of right now, research on exactly how often and in what people proton tunneling in DNA occurs most is ongoing. Seemingly, it appears that because point mutation is such a major cause of genetic mutation aside from environmental concepts, proton tunneling happens most to people whose ancestors also experienced point mutation, much like how one would inherit other traits, such as eye color. Therefore, when one inherits a mutated gene, proton tunneling is likely the method of delivering that mutation. Further research is needed to explain specifics on how proton tunneling would create certain harmful mutations. 

~ Arya Akula

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What is Quantum? [Quantum Explora 2022]