All are electron transport intermediates except:

Explanation

Most electron transport intermediates in mitochondria include cytochromes, coenzyme Q, and flavoproteins, all of which play essential roles in transferring electrons along the electron transport chain to ultimately produce ATP. Cytochromes contain heme groups that alternate between reduced and oxidized states, coenzyme Q is a lipid-soluble carrier that shuttles electrons between complexes, and flavoproteins use flavin nucleotides to transfer electrons from NADH or succinate to coenzyme Q. Ferredoxin, however, is not part of the mitochondrial electron transport chain; it functions in photosynthesis in chloroplasts, making it the exception among these options.