Energy And Life PDF

Preface

This book covers the subject of biological energetics at a breadth suitable to be taken as an individual module of study at the intermediate level of an undergraduate degree. The text takes as its theme the main mechanisms for coupling the free energy of catabolic processes to the reactions necessary for life. The approach is quantitative and detailed molecular structures are not given unless essential for numerical analysis. I make no apologies for this, although I know that numbers are often unpopular with students. I hope that this approach shows some of the beauty of the subject. It is possible to do fairly simple calculations on quite interesting problems. For example, with reasonable assumptions, the time taken for photosynthetic organisms to generate the present-day oxygen atmosphere can be estimated (within a few million years!). The food intake for reasonable body-weight balance can be calculated. It is possible to quantitate the energy needed to warm up the thoracic muscles of a bee before flight. Thermodynamics can be used to analyse living systems, but many of the parameters are unknown and the final quantitative answer may not seem sensible. Sometimes a simple numerical mistake is responsible, but once the calculations have been checked the assumptions behind the calculation need to be examined. For example, see the energy calculations on proton translocation by complex I of the respiratory chain (Figure 7.8).

The text should be suitable for non-specialists in other life-science disciplines who opt to study this topic as an optional module. Of course, depending on the background of the student, some areas will present more difficulty than others. References are therefore mainly from secondary or review literature.

I thank Harold Baum for suggesting the idea for the series and Peter Nicholls for many stimulating discussions on the subject of this volume. I am also grateful to my family for much-appreciated support and encouragement.