REVIEW ARTICLE The mitochondrial compartment

Mitochondria are vital organelles that perform a variety of fundamental functions ranging from the synthesis of ATP through to being intimately involved in pro-grammed cell death. Comprised of at least six compart-ments: outer membrane, inner boundary membrane, intermembrane space, cristal membranes, intracristal space, and matrix, mitochondria have a complex, dynamic internal structure. This internal dynamism is reflected in the pleomorphy and motility of mitochon-dria. Mitochondria contain their own DNA (mtDNA), encoding a small number of vital genes, but this role as a genetic vault is not compatible with the role of mitochondria in bioenergetics since electron transport results in the generation of reactive oxygen species (ROS) that induce lesions in the mtDNA. It is hypoth-esized that ROS shape the morphological organization of the higher plant cell mitochondrial population into a discontinuous whole, and that ROS are a selective pressure affecting the organization of the mitochon-drial genome. This review describes how inter- and intra-mitochondrial compartmentalization underpins the biology of this complex organelle