Transport of proteins into mitochondria

Abstract

Mitochondria and plastids were derived from endosymbiont bacteria about 1-1.5 x 10⁹ a ago, and contain their own DNA (see fig. 15.1). There may be several mtDNA molecules in each mitochondrium, the exact number is species specific. The mtDNA is replicated and the mitochondria divide during the entire interphase. Division of mitochondria starts with an invagination of the inner membrane, the outer follows later. Mitochondrial division is not necessarily coupled to cell division: If for example a muscle is exercised, the number of mitochondria per muscle cell increases. The number of mitochondria per cell can be quite large, about 1000 in a rat liver cell.