ABSTRACT

The mitochondria, which are double-membrane organelles, are the major source of adenosine triphosphate (ATP) in animal cells. These organelles are specialized in oxidizing different types of molecules that serve as fuels to the cells. The electron transfer chain (ETC) and the complex V (ATP synthase/ATPase) form the oxidative phosphorylation (OXPHOS) system that converts the energy obtained from the fuels into ATP. The mitochondria contain circular DNA that encodes for a few mitochondrial proteins and structural RNA. The morphology and the number of mitochondria vary according to the cell type. The synthesis of new mitochondria (mitochondrial biogenesis or mitogenesis) and the destruction of these organelles (mitophagy) lead to alterations in the number of mitochondria depending on the stimulus. Moreover, mitochondrial fusion and fission processes alter mitochondrial morphology. In this chapter, it is presented an overview of basic aspects of the structure and function of mitochondria. Furthermore, the role of mitochondria as a major source of reactive oxygen species (ROS) is discussed.