Values for cellular enthalpy, entropy, and free energy of formation

Values for cellular enthalpy, entropy, and free energy of formation. 

At the present time, values for the thermodynamic properties of cells cannot be found in compendia in the literature. Cells are not pure substances. They have some of the properties of precipitates in that they are insoluble (i.e., they are visible)[37], and do not have standard thermodynamic properties in the usual sense. Nevertheless, a unit mass of anything, impure or otherwise, does have a finite enthalpy, entropy, and fi ee-energy of formation, and this also applies to cells. The unit mass is taken as the ICCmol, represented here by formula (B). Sueh a formula accounts for more than 99% of the total mass, and formulae of this kind are probably the best that can be obtained for something as complex and as variable as different kinds of cells. 

To obtain a value for cellular enthalpy of formation, it is necessary 

It has been recommended [35,36] that AfG values calculated on the basis of a 0.001 m real concentration are more closely representative of the thermodynamic properties of biological systems than conventional A/7 values. This has been adopted here, and the values in this column are therefore 17,11 kJ more negative than those of the aqueous standard state. 

The physical entropy of any mass is a function of the quantity of thermal energy it must abscnb in order to exist at a given temperature above absolute zero, the standard temperature usually being taken at 298.15 K for biological purposes, as represented by the following equation. 

---