Cussedness

Power, Sex, Suicide by Nick Lane

I gave up smoking because of Nick Lane’s first book Oxygen: The Molecule That Made The World, so I approached his latest, Power, Sex and Suicide: Mitochondria and the Meaning of Life with apprehension, fearing that he might induce me to renounce alcohol or chocolate with his command of arcane data and his unrelenting logic. My worries were unfounded; fermentation does indeed get a mention, but only as an alternative to aerobic respiration at a cellular level.

Like Oxygen, this second book of Lane’s is extremely dense, filled with fact-heavy writing, clear and unpatronising, but demanding the full attention of the reader throughout. Regular recapitulation of key points helps to get the important details home, but it is certain that a repeat reading will help to embed the facts and arguments more thoroughly in the disordered mind of an unscientific mortal like me.

The writing itself is lively and engaging, and is embellished with occasional nerdy references to things like Star Wars’ ‘midichlorians‘, Tolkien’s immortal elves, and Douglas Adam’s sarcastic jab at the quest for the meaning of life. The biological details are enlivened by numerous intriguing facts, such as: the voltage generated by respiration across the 5 nanometre-thick inner mitochondrial membrane is 150 millivolts, or about 30 million volts per metre, roughly equivalent to a bolt of lightning. That’s in every mitochondrion in every cell in your body - I calculate that by tapping that energy you personally could send Marty McFly back to the future 10,000,000,000,000,000 times over (given a suitably microscopic DeLorean).

Lane argues that the origin of mitochondria was a fantastically improbable event, and because multicellular life requires mitochondria, the existence of multicellular life elsewhere in universe is similarly unlikely. Sensibly, this avenue of argument is not greatly expanded on, the idea is simply stated and left for the reader to ponder. In contrast, his treatment of how this event actually might have happened is not left unexplored, and he covers the various theories in detail. His discussion of how mitochondria gave rise to the need for two sexes is similarly thorough.

Ageing and death are also explored in great detail, and it becomes clear that mitochondria may well hold the secrets of both these great human preoccupations. Lane notes that birds age much more slowly than other complex lifeforms, and goes on to ask why. The short answer is that they have more mitochondria. Evolution is basically lazy and tries to get away with doing as little work as possible in any given individual. The threshold of minimal work (or maximal laziness) is higher in flying animals (birds and bats) than in terrestrial species like ourselves, so they need more mitochondria in their cells for peak energy production, presumably during take-off and similar extreme exertions. This extra capacity means that, overall, there is less free radical leakage within their mitochondria, because they run at a lower average load, so fewer of them incur DNA damage, and fewer cells succumb to apoptosis (programmed cell death) as a result. Bird tissues lose cells more slowly, and individuals age less rapidly relative to their metabolic rate, so birds get to live relatively longer.

If the previous paragraph makes no sense, blame my imperfect understanding and inadequate expression. Lane has no such problem, and states his case clearly and convincingly, concluding that mitochondria hold answers to many of the big questions that humanity has asked of the universe. He sums it up beautifully in his closing sentences: If [mitochondria] don’t show us the meaning of life, they do at least make some sense of its shape. And what is meaning in this world, if it doesn’t make sense?

3 comments • 2007-04-11 22:04 • Categories: Books, Geek Stuff, Reviews, Science & Maths • Tags: Mitochondria, Nick Lane