Ma'anar ƙamus na cytochrome nau'in sunadaran sunadaran sunadaran da ke ƙunshe da ƙungiyar heme kuma suna taka muhimmiyar rawa a cikin numfashin salula da jigilar lantarki. Ana samun cytochromes a cikin mitochondria na sel eukaryotic da kuma a cikin membranes na sel prokaryotic. Suna shiga cikin jigilar electrons tsakanin kwayoyin halitta a lokacin numfashin salula da kuma photosynthesis. Akwai nau'ikan cytochromes da yawa, kowannensu yana da ɗan tsari da aiki daban.