ABSTRACT
The major net energy conversion catalyzed by the mitochondrion. The process of energy conversion begins when a quantum of light excites a chlorophyll molecule, causing an electron in the chlorophyll to move from one molecular orbital to another of higher energy. Although the chloroplast can be described in similar terms, and several of its main components are similar to those of the mitochondrion, the chloroplast membrane contains some crucial components not found in the mitochondrial membrane. Mitochondria occupy a substantial portion of the cytoplasmic volume of eucaryotic cells, and they have been essential for the evolution of complex animals. Mitochondria are large enough to be seen in the light microscope, and they were first identified during the nineteenth century. Mitochondria are also critical for buffering the redox potential in the cytosol. Mitochondria are also generally believed to be descended from an endocytosed bacterium.
