Life on the Edge

Jim Al-Khalili , Johnjoe McFadden

Why I looked at this book

I'm interested in protein folding and similar topics - the processes which form the basis of life on the microscale - and one of the important features of algorithms used is that they almost entirely use classical physics. Quantum theory must underlie the choice of forces, but it doesn't seem to be needed in doing the calculations. And thank goodness, quantum theory soon leads to intractable calculations, to say nothing about the'does the moon really exist' nonsense that you can get into.

Now this book seems to be claiming that quantum theory is vital in understanding life on the microscale. This seems to go against my understanding of what is going on, so I'm eager to find out more. Is quantum theory ubiquitous, or just involved in a few processes? Is quantum tunnelling important? (I sometimes think this may be relevant to protein folding). I'll read this book with a critical eye.

First impressions

The first chapter looks at the migration of the European robin, telling how it gradually became accepted that quantum entanglement between a pair of free radical electrons in the robin's eye could explain how it could detect the orientation of the earth's magnetic field and use this to navigate. It looks like each chapter gives an example of how quantum theory plays a part in a specific process in a living organism. It's hard to tell so far, though, whether these are just odd examples, or whether quantum theory has this sort of role more generally. I hope to be able to read the rest of the book soon.

Note:In this case the chapter from the Royal society website is longer than the Amazon sample, and it gets on to a discussion of why examples such as the involvement of quantum effects in bird migration were so surprising

Main review

The migratory habits of may not seem a large part of biology, but the book continues with a look at the nature of enzymes, which catalyse biological reactions. 'But that's just chemistry' I thought. There are certainly plenty of chemical catalysts, but apparently there is more to it that that. Enzymes are far more effective than normal chemical catalysts, and the difference is down to quantum tunnelling. Then there's photosynthesis, which is far more effective than it should be according to classical chemistry - again quantum effects come into play. And it seems our sense of smell depends on quantum resonances to be able to distinguish so many different odours.

The chapter on genetics explains how quantum effects play a part in the mutation of DNA, although I felt that this wasn't so convincing as earlier parts of the book and indeed the book seems to get a lot more speculative at this point. The next chapter look at how quantum effects may be involved in consciousness. The authors point that ideas such as those of Penrose aren't taken particularly seriously, but I not sure that I find McFadden's idea of electromagnetic consciousness much more convincing. Then there's a chapter on how the origin of life on Earth may have been helped along by quantum processes.

OK, so it get's a bit speculative towards the end, but I don't think that there's anything wrong with that. By that time I'd already been persuaded that, yes, quantum theory does play an important part in biology. To add to that, while the authors are putting forward their arguments they also introduce the reader to some fascinating areas of science, in an accessible way.

This was the last of the 2015 Winton Prize books I read (most books I get from the library, but I actually went as far as buying this one). I was sceptical about it's message to begin with, but it is persuasive, and I'd choose it as the best of the contenders for the prize.
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