বুধবার, ২৪ অক্টোবর, ২০১২

The molecular machines that make life

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Phil McKenna, contributor

Molecular machines that follow one particular course are fundamental to biology

TEN trillion times a second, the molecules that make up our bodies crash into each other at incredible speed. Somehow, this chaos at the nanoscale gives rise to life. But how?

For thousands of years, philosophers, scientists and theologians have struggled to find the guiding force that creates organised life from disorder. In Life's Ratchet, biophysicist Peter Hoffmann reveals that the secret to life isn't some mysterious force. Rather, it is chaos itself.

Hoffmann provides a ringside perspective on life at its most fundamental level, gained through his work on imaging and manipulating molecules. "Molecular machines", he tells us, are the key to organised life. They harness the energy of the random collisions in a molecular "storm" to move life's building blocks in a single direction.

The book's initial chapters provide an exhaustively researched history of our efforts to make sense of life. My favourite tale is of how scientists in the early 19th century believed that electricity was a vital life force because it made the muscles of dead animals twitch. Their often-horrific experiments were the basis of the science-fiction thriller Frankenstein.

Hoffmann's primary focus is, however, to explain how molecular machines turn chaos into the purposeful movement that allows for organised life. Along the way, readers are exposed to bizarre phenomena found only at the nanoscale, where liquids behave like solids and the rules of classical physics give way to quantum mechanics.

As fascinating as this tiny world is, I struggled to gain a clear sense of how molecular machines operate. One analogy Hoffmann uses is that of a ratchet, which can only be turned in one direction. Under bombardment from all sides, the molecular ratchet harnesses the energy of collisions from only one direction, and is thus propelled forward. So far, so good. But Hoffmann's attempts at more concrete explanations often get bogged down in overly technical descriptions that threaten to suffocate, rather than reveal, life's inner workings.

In endeavouring to describe life, Hoffmann is standing on the shoulders of giants such as Aristotle and Erwin Schr?dinger, the physicist who tried to explain life from first principles in his 1944 book, What is Life?. Schr?dinger began his book by warning his audience that the subject matter would be difficult and could not be termed "popular". It went on to become one of the bestselling science books of all time. Perhaps Life's Ratchet will be similarly well received.

Book information
Life?s Ratchet: How molecular machines extract order from chaos by Peter M. Hoffmann
Basic Books
?18.99/$27.99

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