. "Any constituent part of a mitochondrion, a semiautonomous, self replicating organelle that occurs in varying numbers, shapes, and sizes in the cytoplasm of virtually all eukaryotic cells. It is notably the site of tissue respiration." . . . . "mitochondrial part" . "mitochondrion component" . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .