Life's Ratchet: How Molecular Machines Extract Order from Chaos

Life’s Ratchet

Life’s Ratchet

  HOW  

MOLECULAR MACHINES

EXTRACT ORDER
from
CHAOS

P
ETER
M. H
OFFMANN

BASIC BOOKS

A Member of the Perseus Books Group

New York

Copyright © 2012 by Peter M. Hoffmann

Published by Basic Books,

A Member of the Perseus Books Group

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Designed by Pauline Brown

Typeset in 11.5 point Dante MT Std by the Perseus Books Group

Library of Congress Cataloging-in-Publication Data

Hoffmann, Peter M.

Life’s ratchet : how molecular machines extract order from chaos /

Peter M. Hoffmann.

p. cm.

Includes bibliographical references and index.

ISBN 978-0-465-03336-2 (e-book)

1. Molecular biology. 2. Bioenergetics. 3. Life (Biology) I. Title.

QH506.H636 2012

572'.33—dc23

2012018626

10 9 8 7 6 5 4 3 2 1

To my lovely wife, Patricia,
and my parents, who raised me
to always want to know more.

Introduction

What Is Life?

1
The Life Force

2
Chance and Necessity

3
The Entropy of a Late-Night Robber

4
On a Very Small Scale

5
Maxwell’s Demon and Feynman’s Ratchet

6
The Mystery of Life

7
Twist and Route

8
The Watch and the Ribosome

9
Making a Living

Epilogue

Life, the Universe, and Everything

Glossary

Sources

Suggested Reading

Acknowledgments

Index

Little Fly,

Thy summer’s play

My thoughtless hand

Has brushed away.

Am not I

A fly like thee?

Or art not thou

A man like me?

For I dance

And drink, and sing,

Till some blind hand

Shall brush my wing . . .

—W
ILLIAM
B
LAKE

That crude matter should have originally formed itself according to mechanical laws, that life should have sprung from the nature of what is lifeless, that matter should have been able to dispose itself into the form of a self-maintaining purposiveness—that [is] contradictory to reason.

—I
MMANUEL
K
ANT

A
BLACK SPECK WHIZZES IN FRONT OF MY EYES. Absentmindedly, I swat at it, only to find I have killed a fruit fly. I probably should not be upset, but I have destroyed a living being, an autonomous, moving thing that makes its own decisions, flies around, finds its own food, and knows how to make more copies of itself. I have destroyed a marvelous machine created far beyond the capabilities of our best scientists and engineers. Now, as I look at the dead creature, I wonder: What made this motionless mass of water and organic molecules so happily alive just a moment ago? What does it mean when we say something is “alive”?

I am a physicist, not a biologist. To be honest, my formal biology studies ended when I was in eleventh grade, and I never took a single university-level class in the subject. Why write this book? When I was in high school, I loved science and mathematics, but I could never get too excited about biology. It seemed like a lot of tedious memorization and ad hoc theories and appeared to lack the coherence, clarity, and universality of physics. This remained my opinion for many years while I finished my undergraduate studies in Germany and took off for graduate school in the United States. For a while I was your typical arrogant physicist, getting a good chuckle out of Ernest Rutherford’s quote: “Physics is the only science; all else is stamp collecting.”