Neurodegeneration: the degeneration of neuronal brain cellsEndosymbiosis theory: The theory stating that eukaryotic mitochondria evolved from aerobic bacteria living in their host cellsmtDNA: single circular molecule of mitochondrial DNA that consists of its own genetic material separate from the cellPolypeptides: Amino acid chains that make up proteins. For example, DNA and mtDNA are both proteins that are made up of the amino acids adenine, guanine, cytosine, thymine, and uracilOXPHOS: a.k.a, Oxidative Phosphorylation, which is the metabolic pathway used by mitochondria to release energy (ATP, adenine triphosphate) via the oxidation of nutrients Free radicals: a single atom, or a group of atoms, that have an unpaired number of electrons. When reacted with oxygen they become very reactive, and cause severe damage Substantia nigra: the layer of nerve cells in the brain that is responsible for the production of dopamineApoptosis: the cell suicide process used to get rid of cells that are no longer needed by the organismROS: a.k.a. Reactive Oxygen Species are chemically reactive molecules that contain oxygen and are a natural byproduct of metabolismFussion: processed by large GTPAses to combine fragmented pieces of mitochondria to form new mitochondrial cellsFision: The dynamic process similar to cellular division to help create new mitochondrial cellsMfnl 1,2: Mitofusin (Mfnl) 1 and 2 are proteins that assist in mitochondrial fusion and fissionHeteroplasmy: The point during the mutation process where at the cellular level the mutation can be noticedPoint mutation: a mutation that causes a single base changeOxidative Damage/Stress: caused by an imbalance in ROS and the biological systems ability to detoxify the reactive intermediatesKinase: an enzyme that catalyzes the transfer of phosphate groups from high-energy phosphate donating molecules to specific substrates