Using your Trial 1 data from Procedure II (Data Table II) and Procedure III (Data Table III), and the known concentration of guanine (see Activity Form tab), calculate the concentration of the cytochrome c solution. Activity form: Concentration is a measure of the amount of a substance contained per unit volume. A commonly used unit for the amount of substance is the mole (mol). When used along with the metric unit for volume, concentration may be expressed in mole per liter (mol/L). Often, for the small concentrations associated with biological systems, millimole per liter (mmol/L) may be used to express concentrations. One millimole is 1/1000 of a mole.