Quantum Biology

Quantum Biology

Parallel worlds are not created every time we make a decision, but there are a number of processes that do cause us to branch. Any quantum experiment can have important macroscopic effects if the experimenter places bets on the outcome and so we can create worlds of our choosing in this way. We could, for example, decide to learn to play the guitar if an atom is measured with an 'up' spin state and piano if it is 'down', by doing this we could ensure that we somehow get to do both. This sort of branching would not occur unless we really intend to follow through with each action however, otherwise we will be constrained by free will.

Many forms of technology rely on quantum tunnelling including transistors, microchips, lasers, digital cameras and USB drives. Biology also offers many examples of quantum interactions that have macroscopic effects and if biology has found a way to delay decoherence then this may help us develop quantum computers. Schrodinger was the first to suggest that the genetic code could be regarded as a quantum code, with fluctuations causing mutations, in 1944 (Schrodinger, 1992). It is now known that mutations can be caused by proton tunnelling, a quantum event (Davies, pp.69-79). British-Irish biologist Johnjoe McFadden and British physicist Jim Al-Khalili provided further evidence that the genetic code can be regarded as a quantum code in 1999 (McFadden and Al-Khalili, pp.203-211). In 2001, Indian physicist Apoorva Patel showed that the polymerase enzyme, involved in replicating DNA, picks nucleotides in accordance with the Born rule (Patel, pp.145-151).

In 2007, American chemist Graham Fleming and colleagues showed that photosynthesis, the process which provides fuel for almost all life on Earth, utilises quantum interactions in order to be more energy efficient (Engel et al., pp.782-786). That same year, Spanish biochemists Ismael Tejero and colleagues showed that quantum tunnelling is utilised by antioxidants called catechins, which are found in tea, wine, and some fruits, vegetables and chocolate. They work by neutralising free radicals, ions which can damage cells and react in the bloodstream and would not be able to transfer an electron to the ion without utilising quantum effects (Tejero et al., pp.5846-5854).

Also in 2007, English physicist Marshall Stoneham and colleagues showed that our sense of smell is dependent upon random quantum interactions (Brookes et al., 2007). This theory was first suggested by Lebanon-American biophysicist Luca Turin in 1996 (Turin, pp.773-791). The classical view suggested that different smells were triggered when molecules called odorants enter receptors in our nose, but it was not known why different things smell the way they do as molecules with similar shapes do not necessarily smell like one another. Turin suggested that different smells are related to different frequencies of vibrations which are caused by quantum tunnelling.

References

Brookes, J.C., Hartoutsiou, F., Horsfield, A.P., and Stoneham, A. M., 2007, 'Could Humans Recognize Odor by Phonon Assisted Tunneling?', Physical Review Letters, Vol.98

Davies, P.C.W., 2004, 'Does quantum mechanics play a non-trivial role in life?', BioSystems, Vol.78

Engel, G.S., et al., 2007, 'Evidence for wavelike energy transfer through quantum coherence in photosynthetic systems', Nature, Vol.446

McFadden, J., and Al-Khalili, J., 1999, 'A quantum mechanical model of adaptive mutations', BioSystems, Vol.50

Patel, A., 2001, 'Why genetic information processing could have a quantum basis', Biosciences, Vol.26

Schrodinger, E., 1992, 'What is Life?', Cambridge University Press, Cambridge

Tejero, I., et al., 2007, 'Tunneling in Green Tea: Understanding the Antioxidant Activity of Catechol-Containing Compounds. A Variational Transition-State Theory Study', Journal of the American Chemistry Society, Vol.129

Turin, L., 1996, 'A spectroscopic mechanism for primary olfactory reception', Chemical Senses, Vol.21