Quantum Biology: Understanding the Way We Work

Quantum biology is widely considered to be an emerging theory, although it's certainly not a new concept. In fact, this unique junction where the physics world and the biological world cross paths has popped up multiple times over the last century - Schrödinger, for example, proposed a connection between quantum mechanics and biology back in the 1940's, closely followed by Löwdin in the 1960's - and yet we're still not that much closer to figuring out how strong an association there is between the two, or whether there really is a viable link at all. Quantum biology is still very much an unknown.

Not only are the intricate details of quantum biology not fully understood, but the basic concept is also the source of much confusion. What exactly is meant by 'quantum biology'? At its simplest level, quantum biology refers to the notion that quantum mechanics can be applied to biological processes. Quantum mechanics, of course, is based on the idea that there can be multiple possibilities, even multiple realities, until we determine which possibility, or which reality, is, in fact, 'real'.

There are a number of examples of quantum mechanics in action. Thomas Young's double slit experiment proposed the idea that particles are capable of performing all roles they are capable of undertaking at the same time, until we apply a specific role to the particle. However, Schrödinger's cat is, perhaps, the most famous thought experiment, discussing the notion that a cat sealed in a box is both alive and dead - at the same time - until the box is opened and we can properly determine the animal's fate. Can this be applied to biology?

Counterintuitive Quantum Mechanics

If quantum mechanics can indeed be applied to biology, why is proving the association such a seemingly difficult process? After all, not much progress has been made since Schrödinger's 'What is Life?' was published in 1944. The issue, it appears, is that the laws of quantum mechanics only apply to the smallest structures of the universe. Imagine a tennis ball flying through the air, for example. We can see what the ball is doing - it follows the classical rules of physics - but we can't see what's going on inside the ball, where the particles are adhering to the rules of quantum mechanics. That is, they're performing all possible actions until we're able to determine which actions they're actually undertaking. It's the same for biological processes. The body operates in an organized manner on a larger scale; it's only once we delve deeper and isolate the atoms that we're able to apply the rules of quantum mechanics. Scientists tend to agree that quantum biology is relevant, but the 'why's' and 'how's' are largely unknown.

So what do scientists mean when they say that quantum biology is relevant? They're referring to the concept that, by applying the rules of quantum mechanics to biology, we can obtain a better understanding of basic biological processes. 'There are definitely three areas that have turned out to be manifestly quantum. These three things… have dispelled the idea that quantum mechanics had nothing to say about biology', says Dr Luca Turin of the Fleming Biomedical Research Sciences Centre in Greece. What are these three things? While quantum biology is certainly still an emerging field, it is generally accepted by physicists and biologists that there are three processes that show a stronger link to quantum mechanics than others. These are photosynthesis, avian magnetoreception, and olfaction.

Photosynthesis

There's a common misconception that photosynthesis alone is a specific single process, when really it's more of an umbrella term covering many different types of energy transfer. Due to the presence of different chromophores amongst different plant species, the molecules that absorb sunlight vary considerably. Green plants, for example, contain chlorophyll, whereas red algae contains phycobilin. Therefore, it stands to reason that the transfer of energy would be pretty hit and miss, depending on compatibility between the energy and the molecules.

Therefore, it stands to reason that the transfer of energy would be pretty hit and miss, depending on compatibility between the energy and the molecules. However, according to Johnjoe McFadden, biologist at the University of Surrey, photosynthesis is 95 percent accurate - an accuracy rate that seems almost impossible given the need for this compatibility. McFadden says that photosynthesis is 'more efficient than any other energy transfer known to man'. How can we explain this? Through quantum biology?

One theory that has been put forward is that the rules of quantum mechanics - the idea of multiple possibilities or multiple realities - can be applied to the process of photosynthesis. Many biologists believe that the reason that photosynthesis is so accurate - perhaps too accurate to seem real - is superposition. Superposition is the notion that particles can be present in multiple places at the same time. The concept of superposition is used to support the idea that light energy can target a single plant in a number of different ways simultaneously, in order to quickly identify the most effective and efficient route for energy transfer, regardless of the molecules or chromophores of that specific plant. Scientists are pretty sure that this is the only reasonable explanation, and yet it's still somewhat mystical. Everything we know tells us that superposition shouldn't exist. Everything we're learning tells us it does.
 

Avian Magnetoreception

The migratory patterns of birds aren't a mystery, and we've even discovered how birds navigate - by the position of the sun, by constellation patterns, by noticeable landmarks, and by the landscape. Karl von Frisch, for example, was the first to propose the idea that honey bees navigate by the sun, while William Tinsley Keeton suggested that homing pigeons use landmarks and the landscape to stay on track.

However, there are some species of bird, such as the European robin, that go against the grain. Researchers have determined that the European robin doesn't adopt the same navigational methods as Monarch butterflies, wasps, and other animals. Instead, they use avian magnetoreception, but once again this is a notion that our brains tell us shouldn't be possible. And yet there's no other explanation.Magnetoreception is a navigational method by which some avian and mammal species determine direction by signals drawn from the earth's magnetic field. It's a very controversial concept that has many possible explanations, with one of these being quantum entanglement. Quantum entanglement is, of course, controversial in itself - it's the idea that two particles can be connected, and can even communicate with each other, despite having no physical connection. When applied to avian magnetoreception, quantum entanglement states that particles in two different 'realities' can form a link, enabling both to be viewed at a single time. In terms of the European robin, this suggests that the birds are able to see both the landscape and the earth's magnetic field simultaneously, overlaying one on top of the other and utilizing both as a comprehensive navigational aid during migration season.

Olfaction

The general consensus when it comes to human smell is that we identify smells based upon the individual shapes of the molecules. Based on this concept, it stands to reason that two similarly shaped molecules should smell remarkably similar, and that two very different molecules should create very different aromas. However, this is the subject of much debate, and it's easy to see why. Take hydrogen and sulfur, for example. Both have a significantly different chemical make up, and yet many people agree that both smell like rotten eggs. How can two differently shaped molecules smell the same if the only way we identify smells is through molecular shape? Could there be another force at work here?

Scientists have proposed the idea that molecular shape is only one factor, and that vibrations also play a significant role in determining smell. How do these vibrations occur? It's widely suggested that it all comes down to quantum tunnelling. Quantum tunnelling is the notion that molecules can 'tunnel' through barriers, passing from one receptor to another, creating vibrations during the process. This is used to explain how two similar molecules can behave in very different ways at the same time. Is there much evidence supporting the idea of quantum tunnelling in olfaction? It appears that for every supportive study, there's research that seems to disprove the theory. Turin's 'Molecular vibration-sensing component in Drosophila melanogaster olfaction' reported findings that were 'inconsistent with a shape-only model for smell', showing that it was possible to distinguish between the identically-shaped hydrogen and deuterium. However, Keller and Vosshall came to a different conclusion. Based on the idea that quantum tunnelling plays a role in olfaction, a mixture of guaiacol and benzaldehyde should, in theory, create a vanilla-like smell, as the molecular vibrations are similar to those produced by vanillin. Participants were unable to identify a similarity between the odors.

The Future of Quantum Biology

The potential associations between quantum mechanics and biology have piqued the interest of many scientists, and today much more attention is being given to developing the notions further, and providing more support to the concepts. Johnjoe McFadden and Jim Al-Khalili have established themselves as big names in the quantum biology world, claiming that a better understanding of how the rules of quantum mechanics could apply to the body may lead to a better overview of genetic mutation, development of cancers and other diseases, and the most efficient and effective ways to treat deadly disease.

There are many questions in biology to which we simply do not have the answers. Let's look at M. tuberculosis and E. coli, for example. These bacteria are what keep scientists awake at night. They mutate in different ways, at faster rates, than other bacteria, despite classical rules stating that this sort of mutation shouldn't be possible. These forms of mutation are, however, possible when quantum mechanics laws are applied. Could quantum mechanics hold the answers we've been searching for? It is argued that mutation anomalies such as this could be the result of quantum tunnelling, with atoms tunnelling themselves to the 'wrong side of the tracks' - or rather, the wrong side of the DNA ladder.

A better understanding of quantum biology could also have a significant impact upon the drug industry, both in terms of manufacture and efficiency. In recreating some quantum biology processes artificially, such as photosynthesis, we could potentially see light energy being used to convert carbon dioxide into pharmaceuticals, or new drugs being developed that adopt the basics of superposition, enabling the medicines to target multiple particles simultaneously to determine the most effective route.

Over the past few years, we've made more progress with quantum biology than ever before, and it has become easier to see how a link may exist between the physics world and the biology world. However, it's still very much a 'touchy' subject. In fact, it's one of the most controversial topics in science today. While those that support quantum biology believe that they've finally found the answer to some of the most complex unanswered questions in the field of biological sciences, it's just as easy to argue that these scientists are taking the easy route by essentially assigning a 'magical' label to anything that seemingly cannot be explained through classical rules. Does quantum biology really exist, or are we merely clinging onto a glimmer of hope? Whatever the answer, it's clear that more research into quantum biology is needed.