CHAPTER 7 



A Conceptual Introduction 

 to Bioenergetics 



Thermodynamics is a queer science. It is a system of logic based on three 

 postulates which have never been proved or disproved. By clever juggling 

 with symbols and ideas, it establishes relations between different forms of 

 energy .... These are most interesting relations which allow us to peep 

 behind the scenes of Nature's workshop .... Thermodynamics may yet tell 

 us how Nature molds such complex phenomena as muscular contraction out 

 of simpler reactions . (A. Szent-Gyorgyi. 7 ) 



INTRODUCTION 



Scope 



The manipulation of the energy available from many natural sources has 

 been a problem of deep concern to man since the realization of the facts of 

 motion. Then came the mastery of fire; the kinematic machine; the use of 

 chemicals for ballistic purposes; and the water wheel for milling, and later 

 for producing the most versatile energy form of them all: electricity. Our 

 age is witnessing the development of the peaceful uses of atomic energy, the 

 energy of nuclear reactions; and a slower but perhaps more far-reaching de- 

 velopment of methods of trapping and storing the sun's radiation as heat, 

 and chemical and electrical energy. 



Thermodynamics is the study of general principles which relate to trans- 

 fer of energy from one form to another (Figure 7-1). By contrast with some 

 of the more clearly understood systems, bioenergetics is still in its infancy, 

 although biochemists have done much toward describing the energetics of 



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