30-SECOND BIOCHEMISTRY 30-SECOND BIOCHEMISTRY The 50 vital processes in and around living organisms, each explained in half a minute Editor Stephen Contakes Contributors Stephen Contakes Steve Julio Kristi Lazar Cantrell Ben McFarland Vassilis Mougios Anatoli Petridou Andrew K. Udit Illustrator Steve Rawlings First published in the UK in 2021 by Ivy Press An imprint of The Quarto Group The Old Brewery, 6 Blundell Street London N7 9BH, United Kingdom T (0)20 7700 6700 www.QuartoKnows.com Copyright © 2021 Quarto Publishing plc All rights reserved. No part of this book may be reproduced or transmitted in any form by any means, electronic or mechanical, including photocopying, recording or by any information storage-and-retrieval system, without written permission from the copyright holder. British Library Cataloguing-in- Publication Data A catalogue record for this book is available from the British Library. ISBN: 978-0-7112-6367-3 eISBN: 978-0-7112-6369-7 Commissioning Editor Caroline Earle Designer Ginny Zeal Illustrator Steve Rawlings Glossaries Text Stephen Contakes Printed in China 10 9 8 7 6 5 4 3 2 1 CONTENTS 50 Machinery 106 Reading the Book 52 GLOSSARY 108 Doctoring Decoding: Epigenetics 54 Protein Folding & Aggregation 110 Finding the Source 56 Shape: Protein Structure 58 Profile: Max Perutz 112 Staying Alive 60 R oads & Rafters: Structural 114 GLOSSARY Proteins 116 In & Out: Digestion & Excretion 62 Motors 118 Blood, Breath & Balance 64 Transport & Storage 120 Moving 66 M embranes, Messengers 122 Profile: Hugh Huxley & Receptors 124 Biochemistry on the Brain 68 Making Life Go: Enzymes 1 26 Detox 6 Introduction 128 Electrolyte Balance 70 Harvesting Energy 130 Coordinating the Defence 10 Biochemistry’s Context 72 GLOSSARY 12 GLOSSARY 74 Life’s Currency 132 In Sickness & Health 14 Life’s Scale 76 Using Big Carbs 134 GLOSSARY 16 Life’s Units 78 Using Small Carbs 136 Things We Need 18 Life’s Power 80 L ong-term Storage 138 Staying Fit 20 Life’s Rules & Burning Fats 140 Progeny & the Pill 22 Life’s Matrix 82 The Central Hub 142 Maintaining the Right Balance 24 Life’s Give & Take 84 Profile: Hans Krebs 144 Repelling the Hijackers 26 Profile: Lawrence Henderson 86 ATP From Air 146 Profile: Gertrude Elion 28 Life’s Organizing Force 88 Mobilizing the Cell & George Hitchings 148 When Cells Break Bad 30 Building Blocks 90 Making Life 150 Gene Editing 32 GLOSSARY 92 GLOSSARY 34 Elements 94 B urning in Reverse: 152 Appendices 36 Bonds: Life’s Handedness Photosynthesis 154 Resources 38 Chains: Biological Polymers 96 Bringing in the Nitrogen 156 Notes on Contributors 40 Lipids 98 Pooling the Amino Acids 158 Index 42 Sweetness: Carbohydrates 100 T he Making of the 160 Acknowledgements 44 Profile: Frederick Sanger Message Bearers 46 Life’s Letters: Nucleotides 102 Maintaining the Code 48 Workforce: Amino Acids 104 Profile: James Watson, Francis & Peptides Crick & Rosalind Franklin INTRODUCTION Stephen Contakes Biochemistry deals with life, a concept difficult to pin down but which may be roughly understood as comprising parts of the natural world that are distinct from their surroundings, can take in and use energy to sustain themselves, and reproduce. It examines life in terms of atoms and collections of atoms called molecules. Over the past two centuries the merger of chemistry and biology in biochemistry has yielded an increasingly detailed understanding of how living things work. This has especially been the case from the twentieth century onwards as chemists and physicists have developed powerful tools for probing the composition and structure of matter at the molecular level. Through these it is now possible to separate living things into their molecular components with incredible resolution, determine their three-dimensional structures, follow the chemical reactions taking place in living things and determine how biomolecules perform the functions they do. The power of a molecular perspective in the life sciences was aptly summarized by Francis Crick: ‘Almost all aspects of life are engineered at the molecular level, and without understanding molecules we can only have a very sketchy understanding of life itself.’ The aim of this book it to develop an understanding of life by describing molecules and how they work together in living systems. It does so using brief digestible introductions to 50 important ideas in biochemistry. As with other titles in the series, this book does not attempt to give a systematic in-depth survey of biochemistry. Some of the entries in which the important ideas are presented explain key concepts or foundational principles that govern the behaviour of biological molecules. Others describe how molecules work individually or as part of larger systems to perform biological functions. Interspersed throughout are vignettes that present biochemistry as a human enterprise. Together these are intended to give you a sense for how life works at the molecular level and to help you see that there are always opportunities for bright and enterprising scientists to further our understanding of biochemistry. 6 g Introduction How this book works Each entry is broken into several parts. The 30-second structure and 3-second nucleus summarize the main idea. In particular, the 30-second structure gives the body of that explanation while the 3-second nucleus summarizes it in a sentence or two. In contrast, the 3-second biographies and 3-minute system explain how the main idea fits in a wider context. The 3-second biographies introduce scientists who contributed to the idea’s discovery or development. The 3-minute system expands on the main idea by explaining how it works in another context or how it applies in interesting situations. Although each entry is capable of being read individually, it helps to begin with foundational principles before applying them to increasingly complex systems. The book begins by considering biochemistry’s context, specifically its scope and the key physical principles that govern how molecules act in living systems. Next, the building blocks that make up life are described, followed by a more detailed look at the protein machinery that does much of the work of the cell. Then follow three sections that explore how collections of biomolecules work together to harvest energy, make the molecules of life and help complex multicellular organisms such as us stay alive. Finally, the way in which these processes can be disrupted for good or harm is explored in a section dealing with sickness and health. Fittingly, the final entry explores how biochemistry functions both as a way of making sense of life and transforming it, specifically through inexpensive and easy-to-use technologies for editing the information- bearing DNA molecules that shape the character of living things. 8 g Introduction