About Me

My photo
I live in Bedford, England. Having retired from teaching; I am now a research student at the University of Bedfordshire researching into Threshold Concepts in the context of A-level Physics. I love reading! I enjoy in particular fiction (mostly great and classic fiction although I also enjoy whodunnits), biography, history and smart thinking. I have also recently become a keen playgoer to London Fringe Theatre. I enjoy mostly classics and I read the playscripts and add those to the blog. I am a member of Bedford Writers' Circle. See their website here: http://bedford-writers.co.uk/ Follow me on twitter: @daja57

Wednesday, 25 May 2016

"Life on the Edge" by Jim Al-Khalili and Johnjoe McFadden

This book is about Quantum Biology.

The essential thesis of this work is that life is too ordered to have developed by chance from the random fluctuations of thermodynamics. Each living cell requires the coordination of a number of organelles; even the molecules of RNA which might have formed the first replicating molecules are highly complex and ordered. Enzyme processes which are the fundamental processes of life are carefully structured, although the language that this book uses (the enzymes unzip, cut, select etc) tends to prejudice one's thinking towards assigning a purposeness which the enzymes may not possess. Instead of thermodynamics, the authors propose that life requires the more ordered processes of quantum physics.

The two effects they believe are most useful to life are quantum tunnelling and quantum entanglement. Quantum tunnelling makes use of the wave nature of particles; since the particle wave means that the particle is delocalised in space it has a possibility that it is on the far side of an energy barrier so that it can react even when the energetics suggest it won't. The delocalisation also makes possible 'quantum search': instead of randomly trying out one combination after another you can explore all possibilities at the same time.

But the problem with quantum effects is that they are on a very very small scale and that the waviness feature can be disrupted by 'measurement' which in practice means interaction with another particle. Given how busy and crowded and hot the inside of a cell is, it seems surprising that there isn't a permanent state of decoherence. But these authors suggest that the cell uses tricks to ensure coherence for long enough for the necessary actions for life can take place; in one occasion they suggest that this takes place by a synchronising of oscillations within the cell which is the same thing as is suggested by Stephen Strogatz in Sync.

This is a serious scientific book and they provide great evidence for what they are suggesting. But at the end I was unsure how important it all was. There are electrons and protons inside the molecules that make up cells and these very tiny particles inhabit the quantum universe and follow quantum rules. So it is surely inevitable that the chemical reactions that make and are used by enzymes utilise quantum mechanics, after all, chemistry is all about electron transfer. There surely is no dispute about this. I think what they are suggesting is that the fact that quantum physics underpins the chemistry means that the odds on the spontaneous generation of life are much better than they first appear.

OK. It is obviously harder than we first thought to create life. Even the simplest organisms we know have extraordinarily complex internal structures. If it is too difficult to create complex molecules by random reactions then we are left with the possibility that life wasn't generated in the early history of this planet but was either created or arrived from elsewhere (although this still begs the question of how it arose elsewhere). But if quantum effects makes it too easy to create complex molecules than why was life apparently only created once? (These authors seem to suggest that the complex molecules somehow competed and only one life form remained after natural selection had taken place but if it really is that easy to create complex molecules why has this process only happened when the earth was very young?) In the end you have to assume that there is only one type of life that is viable but that it is relatively easy to spontaneously generate this form. After all, astrobiologists tell us that there are very few elements which have the appropriate reactions so that it is almost certain that only carbon-based life forms can exist in this universe.

This was an incredibly well-written book with lots of lovely asides (mostly about the bizarre life histories of the scientists mentioned) and it explains some really difficult stuff superbly well. I am not sure to what extent I was convinced by the thesis but it was great fun reading it.

May 2016; 433 pages

No comments:

Post a Comment