Chapter 7 – Role of subcellular organelles: inter-relationships of the mitochondria and cytosol

Publisher Summary The chapter discusses the inter-relationships and the roles of the mitochondria and cytosol. The main functions of the cytosol can be described as preparation of metabolites for oxidation in the mitochondria and synthesis of important food stores such as fat and glycogen, and the main function of the mitochondria as provision of an energy supply for synthesis of molecules required in the cell and other processes. Energy generated in the mitochondria is normally in the form of chemical energy, ATP, but the energy derived from oxidation processes can also be diverted to produce heat or accumulate Ca2+. Many enzymes that utilize ATP, including those involved in synthetic processes, are located outside the mitochondria; consequently a large traffic in ATP from mitochondria to cytosol must be essential for efficient functioning of the cell. Alternatively, ATP-requiring metabolic processes that originate in the cytosol may be diverted into the mitochondria so that ATP is utilized there and the products returned to the cytosol.