Quantum mechanics in biological processes

Can classical physics explain migratory birds’ long distance navigation?

Here are some biological processes where quantum phase coherence or other quantum phenomena have been suggested to play a role:

  1. Birds’ Magnetic Navigation: European robins and other migratory birds are thought to use a quantum process known as “quantum entanglement” to navigate using Earth’s magnetic fields. This is described by the “Radical Pair Mechanism,” where certain biochemical reactions in the bird’s eye create entangled electron pairs that are affected by Earth’s magnetic field, allowing the bird to sense direction.
  2. Photosynthesis: In plants, algae, and some bacteria, the process of photosynthesis appears to exploit quantum coherence to enhance the efficiency of energy transfer. The idea is that excitons (quantum states that are a mixture of an electron and an absence of an electron) can exist in multiple states simultaneously and search for the most efficient path for energy transfer, thanks to quantum coherence.
  3. Smell: The mechanism of olfaction (smell) is not well understood, but some theories propose that electron tunneling, a quantum phenomenon, may be involved in odor detection. This tunneling might allow for more sensitive differentiation between different molecules.
  4. Enzyme Catalysis: Enzymes often catalyze biochemical reactions much faster than what would be predicted by classical models. Some theories propose that this is because the enzymes utilize quantum tunneling to get reactants over energetic barriers.
  5. DNA Mutation: Some theories suggest that quantum tunneling might also play a role in the mutations of DNA, although this idea is much less substantiated than the others mentioned here.
  6. Hydrogen Bonding in Water: While not unique to biological systems, water’s hydrogen bonds have been proposed to have quantum coherent properties that are essential for many biological processes. Water is a critical component of life, and its unique properties are essential for proteins and other biological molecules to function correctly.
  7. Microtubules in Neurons: This is a highly speculative area, but some researchers have proposed that quantum coherence in the microtubules of neurons may be important for consciousness. This idea is largely controversial and not widely accepted within the scientific community.

It’s essential to be cautious when discussing quantum biology. While it’s a tantalizing area of study that could revolutionize our understanding of biological processes, many of the ideas are still theories and have not been definitively proven. Experimental evidence is challenging to obtain, and not all scientists are convinced of the role of quantum phenomena in these biological processes.

In summary, quantum processes in biological systems can be affected by tiny disturbances in the environment that classically would be thought to have no effect at all. What might have been seen as magic in a previous era is now beginning to be understood by science albeit with a lot of effort.