FIGURE 2-6 Relative energies of covalent bonds and noncovalent interactions. Bond energies are defined as the energy required to break a particular type of linkage. Shown here are the energies required to break a variety of linkages, arranged on a log scale. Covalent bonds, including single (C–C) and double (C=C) carbon-carbon bonds, are one to two powers of 10 stronger than noncovalent interactions. Noncovalent interactions have energies somewhat greater than the thermal energy of the environment at normal room temperature (25°C). Many biological processes are coupled to the energy released during hydrolysis of a phosphoanhydride bond in ATP.