Introduction

Abstract

One of the major functions of mitochondria from all organisms is to provide ATP as the principal energy source for the cell. This is true also of plant mitochondria and it is therefore no surprise that many basic features of mitochondrial membranes have been conserved between animals and plants despite a billion years of divergent evolution. Thus the morphology of plant mitochondria closely resembles that of their animal counterparts (the basic features are depicted in Fig. 1), as do their cytochrome chain, ATPase complex, energy conservation (H⁺ ejection) mechanisms, and membrane phospholipid composition. The latter point is illustrated by the data in Table 1: the pattern of phospholipids in membranes from both photosynthetic and nonphotosynthetic plant mitochondria and from human heart mitochondria are virtually identical. Presumably these basic features of mitochondrial membranes are essential for their functioning in energy transduction.