Is it farther or further?
cytochrome cy·to·chrome (sī'tə-krōm')
Any of a class of iron-containing proteins important in cell respiration as catalysts of oxidation-reduction reactions.
Any of a class of usually colored proteins that play important roles in oxidative processes and energy transfer during cell metabolism and cellular respiration. Cytochromes are electron carriers. They contain a heme group and are similar in structure to hemoglobin and chlorophyll. The most abundant and stable type is cytochrome c. By comparing different kinds of cytochromes, scientists can trace the evolutionary relationships of the organisms in which they occur.