- Daniel González Cappa
- BBC News World
If we took a few minutes to think about quantum physics, what would you say?
Many people would argue that they are complicated formulas that explain very complex processes related to subatomic particles, gravity, energy, the motion of galaxies, black holes, and everything related to space-time and the size of the planet. universe.
A bit like Albert Einstein. And that would not be an exaggerated answer.
After all, the father of the theory of relativity laid the foundations of statistical physics and quantum mechanics, which are part of modern physics, which is very different from the physics proposed by Isaac Newton centuries ago.
But there is a less explored branch that does not require going very far to understand what it is.
In fact, he is here, on our planet, among us.
Iraqi British theoretical physicist Jim Al Khalili posed this in 2015 with a question during a conference: What if the quantum world played a major role in the functioning of a living cell?
Can something so small help us understand why we are alive?
For many years, the scientific community was adamant that biology was such a complex science that it had nothing to do with the quantum world.
An idea that, today, is considered wrong. In fact, quantum mechanics plays such an important role in biological processes that it is vital for plant photosynthesis or cellular respiration.
This branch of science is known as quantum biology.
And understanding that would open the door to countless answers and ideas that we still don’t fully understand, whether it’s understanding how mutations work, creating new drugs, or improving quantum computing.
“To some extent, we are solving an important mystery,” Vladimiro Mujica, a chemist at the Central University of Venezuela and a doctor of quantum chemistry from Uppsala University in Sweden, told BBC Mundo.
Recently, Arizona State University, where Mujica currently works, received a $ 1 million grant from the Keck Foundation, along with the University of California, Los Angeles, and Northwestern University in Chicago, to study quantum biology during the next three years.
The idea is to understand as much as possible the scope of this branch, which is revolutionizing the way we understand the relationship between quantum processes and life itself.
But what is quantum biology?
Let’s start at the beginning. Quantum mechanics:
Modern physics is based primarily on two branches that study relativity and the quantum world. The first studies areas such as the motion of galaxies and planets; the second studies the atomic and subatomic systems that are so small that we cannot see them with the naked eye.
A giant world and a small world.
The obvious side is that chemistry, biology and biochemistry are all part of matter. And this matter is made up of atoms and molecules.
Therefore, if quantum physics studies this atomic world, it also describes biology.
“Biological processes are actually quantum systems because (quantum) physics describes the behavior of matter at the microscopic level,” says Mujica.
It is a very simple conclusion. But it wasn’t always so obvious.
And there is a good reason: biological processes are really very complex. Quantum systems, on the other hand, need “stability,” which scientists call wave coherence.
The conclusion of the scientific community was then that biological processes were so “noisy” that they did not present this stability. Basically, they were destroying consistency.
And so, throughout the twentieth century, scientists separated quantum mechanics from biology. They didn’t pay much attention to him.
But maybe something was missing that scientists didn’t quite understand or didn’t quite fit. Perhaps there was a method where all this was applied in biological processes.
Isn’t it insignificant?
We already know that matter is made up of particles. Some are protons and neutrons, and others are known as elementary particles, such as electrons and photons.
These particles work at the biological level. For example, photosynthesis in plants is driven by the transfer of electrons to molecules.
But there is a problem: how does this electron travel. If we had a light bulb, the electron would pass through a copper wire that heats up a lot and causes the light to come on.
But plants do not have this copper wire. In fact, biology has “bad” energy conductors, according to Mujica, and a sudden rise in temperature would cause the cell to die permanently.
Therefore, the electron would need this that scientists do not understand. A simple process that does not require too much energy to allow the particle to travel without killing the cell.
This process actually exists, and is called the tunneling effect.
An example: if we have a tennis ball on one side of a court and we have to carry it on the other side, we simply throw it from one end to the other.
But if the court has a very high wall in the middle, the ball must be thrown very high and above the wall, otherwise it will bounce. This is how classical physics works.
But it is different in quantum physics. If the tennis ball was really an electron, there is a way to go through the wall, not over it. And this is because the particles move in the form of waves.
The tunnel effect is like “opening a hole in the barrier and sliding.” And the advantage is that it is so simple and so cheap that it is used by biological systems to use as little energy as possible.
Scientists call these events “non-trivial.” This is basically how quantum mechanics alters biological processes.
It’s not new. Physicists such as the Austrian Erwin Schrödinger had already addressed this and other topics in quantum physics in the first half of the twentieth century, thus preparing the ground for someone else to make new discoveries.
But the tunneling effect is not the only quantum mechanism that works in biological processes.
There are others, such as the direction in which the particle rotates, called the spin. And all these effects act in different ways at different stages of biological processes.
For example, photosynthesis takes place in three stages. The first is the capture of the photon (the particle that carries electromagnetic radiation, such as sunlight) by the plant.
The second is where electrons absorb photonic energy and pass to a higher energy state, passing through molecules and depending on the tunnel.
Finally, the electron is used for a chemical reaction that results in the release of oxygen. And this is what allows human beings to breathe.
In all these steps, quantum mechanics is present.
But now imagine that the electron rotates on its own axis, and that this motion can be to the right or to the left. Depending on the direction of rotation, the electron may or may not pass through the tunnel.
For simplicity, think of a screw that, once inserted into the slot, can only be screwed in the correct way. But if you try it on the other side, it will either not work or you will damage it.
This is called chirality, from the Greek kheir, which means hand. When an object is chiral, it has another object which is the reflection, such as the right hand with the left hand.
This means that the turn goes hand in hand with chirality.
“So now you have a privileged mechanism that protects electronic transport from any outside noise. So an effect that shouldn’t have been important now is,” Mujica sums up.
And understanding this is very important for science. We now know that tunnel, spin, and chirality are related not only to photosynthesis, but also to protein synthesis, the way organisms breathe, or the connection between neurons.
Even in mutations, the transformations of genetic material that occur through the random change of a molecule in our body.
But then what is it for?
Scientists are just trying to understand the true dimension of quantum biology. After all, for a long time it was considered unimportant, and it was only about ten years ago that this scientific field began to re-emerge.
One branch that can benefit from this is pharmacology, where chirality plays an important role.
Quantum computing is another. “At this point, we are trying to find good systems for doing quantum processing,” says Mujica. “Quantum computers already exist, but they are very limited. They are very advanced and very expensive toys,” he added.
But many of these applications will not see the light of day in the three years that Mujica and his colleagues will dedicate to the study of quantum biology. They see it more as a science that will have significant long-term effects.
What is clear now is the crucial role that quantum physics plays in helping us understand the workings of the very important biological processes that make life possible.
So it’s not just a matter of looking for other planets, but of looking at what we have on our own planet.