Mitochondria, oxygen free radicals, and apoptosis

Reactive oxygen species (ROS) generated by mitochondria are produced as by- products of normal oxidative metabolism. The fate of these species is gover ned by a number of factors that vary from tissue to tissue in mammals and m ay be involved in the pathogenesis of disease. Reactive oxygen species are also invoked as agents that are important in the processes which become act ive in cells undergoing apoptosis. Integration of knowledge surrounding the se different aspects of ROS generation is difficult and reveals considerabl e gaps in our understanding. (C) 2001 Wiley-Liss. Inc.