In thermodynamic terms, formation of the solution occurs with a fa vorable free-energy change: ΔG = ΔH - TΔS, where ΔH has a small positive value and… - Albert L. Lehninger

Water is a polar solvent. It readily dissolves most bio­ molecules, which are generally charged or polar com­ pounds (Table 2-2); compounds that dissolve easily in water are hydrophilic (Greek, "water-loving"). In contrast, nonpolar solvents such as chloroform and benzene are poor solvents for polar biomolecules but easily dis­ solve those that are hydrophobic-nonpolar molecules such as lipids and waxes.

The current understanding that all organisms share a common evolutionary origin is based in part on this observed universality of chemical intermediates and transformations, often termed "biochemical unity."

The upper limit of cell size is probably set by the rate of diffusion of solute molecules in aqueous systems.