In the middle of the last century, the Austrian physicist Erwin Schrödinger was the first to try to explain the phenomenon of life using quantum mechanics. Now enough data has accumulated to build hypotheses about how quantum effects arise in the body and why they are needed there at all. RIA Novosti talks about the latest advances in quantum biology.
Schrödinger's cat is rather alive
In his book What is life from the point of view of physics ?, published in 1945, Schrödinger describes the mechanism of heredity, mutations at the level of atoms and molecules through quantum mechanics. This contributed to the discovery of the structure of DNA and pushed biologists to create their own theory based on rigorous physical principles and experimental data. However, quantum mechanics is still outside its scope.
Nevertheless, the quantum direction in biology continues to develop. His followers are actively looking for quantum effects in the reactions of photosynthesis, the physical mechanism of smell and the ability of birds to sense the Earth's magnetic field.
Photosynthesis
Plants, algae and many bacteria derive their energy directly from sunlight. To do this, they have a kind of antennae in cell membranes (light-harvesting complexes). From there, a quantum of light enters the reaction center inside the cell and starts a cascade of processes that ultimately synthesize the ATP molecule - the universal fuel in the body.
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Scientists pay attention to the fact that the transformation of light quanta is very efficient: all photons fall from the antennas into the reaction center consisting of proteins. There are many paths leading there, but how do photons choose the best one? Maybe they use all the paths at once? This means that it is necessary to admit the superposition of different states of photons on each other - quantum superposition.
Experiments have been carried out with living systems in test tubes, excited by a laser, to observe quantum superposition and even a kind of "quantum bit", but the results are inconsistent.
Quantum effects in biology / Illustration by RIA Novosti / Alina Polyanina, Depositphotos.
Bird compass
A bird called "little shawl" makes a non-stop flight from Alaska to New Zealand across the Pacific Ocean - 11 thousand kilometers. The slightest mistake in direction would cost her her life.
It has been established that birds are guided by the Earth's magnetic field. Some migratory singing species sense the direction of the magnetic field to within five degrees.
To explain the unique navigational abilities, scientists put forward a hypothesis about a built-in bird's compass, which is composed of magnetite particles in the body.
According to another point of view, on the retina of the bird's eye there are special receptor proteins that are turned on by sunlight. Photons knock electrons out of protein molecules, turning them into free radicals. Those acquire a charge and, like magnets, react to a magnetic field. Its change is capable of switching a couple of radicals between two states that exist as if simultaneously. The birds are supposed to sense the difference in these "quantum leaps" and correct their course.
Smell
A person distinguishes thousands of smells, but the physical mechanisms of smell are not fully known. Once on the mucous membrane, a molecule of an odorous substance meets a protein molecule that somehow recognizes it and sends a signal to nerve cells.
There are approximately 390 types of human olfactory receptors that combine and perceive all possible odors. It is believed that the odorous substance opens the receptor-lock like a key. However, the odor molecule does not change chemically. How does the receptor recognize it? Apparently he senses something else in this molecule.
Scientists have suggested that electrons tunnel (pass energy barriers without additional energy) through odor molecules and carry some information code to receptors. Attempts of the corresponding experiments on fruit flies and bees have not yet yielded intelligible results.
“The behavior of any complex system, in particular a living cell, is determined by microscopic processes (chemistry), and such processes can only be described by quantum mechanics. We simply have no alternative. Another question is how effective this description is today. Quantum mechanics of complex systems - this is called quantum informatics - is still in its infancy”, - comments to RIA Novosti Yuri Ozhigov, an employee of the Department of Supercomputers and Quantum Informatics of the Faculty of Computational Mathematics and Cybernetics, Lomonosov Moscow State University.
The professor believes that progress in quantum biology is hindered by the fact that modern physical devices are sharpened for inanimate objects, it is problematic to carry out experiments on living systems with their help.
“I hope these are temporary difficulties,” he concludes.
Tatiana Pichugina