Table of Contents
Preface ix
Acknowledgements xiii
About the Authors xv
Chapter 1 Introduction 1
1.1 Why Study Photosynthesis? 1
1.2 History 2
1.2.1 The discovery of photosynthesis 2
1.2.2 The concept of energy 5
1.2.3 Early research on photosynthesis 7
1.2.3.1 What absorbs the light for photosynthesis? 7
1.2.3.2 What goes in, and what comes out? 8
1.2.3.3 Which atoms go where? Is it possible to answer this question? 10
1.2.3.4 How much light is required to drive photosynthesis? 13
References 14
Chapter 2 The Photosynthetic Apparatus 17
2.1 Introduction 17
2.2 Chloroplasts 17
2.3 Thylakoid Membrane and Photosynthetic Protein Complexes 20
2.4 Pigments 23
2.5 Lipids and Proteins 23
2.6 Evolution 26
References 26
Chapter 3 Basics of Photosynthesis: Light-Dependent Reactions 29
3.1 Overview: Harvesting Sunlight to Drive Redox Chemistry 29
3.2 Capturing the Energy of Light 29
3.3 Conversion of Light Energy into Chemical Energy 36
3.3.1 Primary photochemistry 36
3.3.2 Electron-transfer pathways 41
3.3.2.1 The "Z-scheme" of photosynthesis 41
3.3.2.2 Photosynthetic water oxidation (oxygen evolution) 43
3.3.2.3 Unique role of bicarbonate in light-induced reactions of PSII 44
3.3.2.4 Formation of reducing power 45
3.3.3 Proton-transfer pathways and formation of ATP (photophosphorylation) 46
References 51
Chapter 4 Basics of Photosynthesis: The Carbon Reactions 59
4.1 C3 Photosynthesis: The Calvin-Benson Cycle 59
4.2 C4 Photosynthesis: The Hatch-Slack Pathway 63
4.3 Crassulacean Acid Metabolism 69
4.4 Translocation and Biomass Production 71
4.5 Alternate Pathways and Evolution 74
References 75
Chapter 5 Regulation of Photosynthesis 81
5.1 Background 81
5.2 State Transitions 82
5.3 Safety Valve: Dissipation of Electronic Energy as Heat ("Quenching") 86
5.4 Xanthophyll Cycles 87
5.5 Reaction Centers as Sinks for Excess Excitation Energy 90
5.6 Quenching of Chlorophyll Triplets 93
5.7 Regulation of RuBisCO 94
5.8 Redox Regulation of Certain Calvin-Benson Cycle Enzymes by Thioredoxin 95
5.9 Other Regulatory Mechanisms Related to Photosynthesis 96
5.10 Leaf Movement 97
5.11 Concluding Remarks 97
References 98
Chapter 6 Photosynthesis and Our Planet 107
6.1 Oxygenation of the Earths Atmosphere 107
6.2 Protection: Ozone Was Formed From Oxygen and It Protects Us From the UV Radiation 108
6.3 Earth Temperature Over Time and the Effect of the Biosphere on It 110
6.3.1 Influence of the Sun 110
6.3.2 Influence of the Earth's atmosphere 111
6.4 Conclusion 115
References 117
Chapter 7 Anoxygenic Photosynthesis 123
7.1 Introduction 123
7.2 Anoxygenic Photosynthetic Organisms: Their Reaction Centers and Pathways for Carbon Assimilation 125
7.3 Relation between the RCs of Anoxygenic and Oxygenic Photosynthetic Organisms 127
7.4 Photosynthetic N2 Assimilation 128
7.5 Rhodopsin-Based Phototrophy 131
References 132
Chapter 8 The Past, Present and the Future 135
8.1 Spread of Photosynthesis by Successive Endosymbiosis 135
8.2 Adapting Photosynthesis that has Evolved Underwater for Life on Land 140
8.2.1 Grana 141
8.2.2 Hormones 142
8.2.3 Stomata 143
8.2.4 Reaching for light 145
8.2.4.1 Evolution of trees 145
8.2.4.2 Cheating: Lianas (Climbers) and Epiphytes 145
8.3 The Role of Fungi 145
8.4 Making More Photosynthesis… More Biomass, More Bioenergy, New Chemicals and Hydrogen 146
8.4.1 General: Classical breeding and genetic engineering 146
8.4.2 Conversion from C3 to C4 metabolism by genetic engineering 146
8.4.3 Cyanobacterial genes in higher plants 147
8.4.4 Improvement of RuBisCO 148
8.4.5 Photorespiratory bypass 149
8.4.6 Photosynthetic H2 production 149
8.4.7 Biofuels and other chemicals 152
8.4.8 Other improvements 152
References 153
Chapter 9 The Ultimate: Artificial Photosynthesis 165
9.1 Objectives and Approaches 165
9.2 Water Oxidation Coupled to Hydrogen Production: in Principle Simple, in Practice Not So Easy 166
9.3 Reduction of Carbon Dioxide 172
9.4 Conclusions 176
References 177
Index 183
