DNA (deoxyribonucleic acid): A two-stranded molecule that contains the genes, or blueprints, for the makeup of a person’s body.
mtDNA: Mitochondrial DNA, the blueprint for the makeup of the mitochondria.
Mitochondria are the only part of the body with their own separate unique DNA.
Mitochondrial DNA is entirely inherited from the mother.
nDNA: Nuclear DNA; located in the nucleus of the cell, this DNA contains the blueprints for the cells which make up the body.
Electron Microscopy: Use of the electron microscope. This special microscope uses a stream of electrons (charged particles) instead of light to illuminate the tissues being studied. Much greater magnifications are possible using this method.
Electron Transport Analysis: A study of the complexes involved in the “respiratory chain” chemical reactions that take place inside the mitochondria.
Enzyme: A protein that speeds up a chemical reaction or causes a chemical change in another substance. Enzymes do their work without being changed or used in the process.
Gene: The fundamental unit of heredity. Genes are located on the strands of DNA found in the cells and mitochondria.
Geneticists: A specialist in the study of genes & heredity.
Histochemistry: The study of the chemical reactions that take place in the cells.
Lactate: A chemical derivative of lactic acid. Lactic acid is formed when sugars are broken down for energy without the presence of oxygen (anaerobic metabolism).
Maternal Inheritance: Genes are passed from one generation to the next through the mother. Mitochondrial genes demonstrate this pattern of maternal inheritance.
Metabolism: All the chemical reactions that happen in the body. Taken together, these reactions create the energy the body uses for all its work including, breathing, thinking & moving.
Mitochondrion: The part of the cell that is responsible for converting nutrients into energy as well as many other specialized tasks.
Muscle Biopsy: A patient is placed under general anesthesia and an inch long incision is made into the thigh muscle. A sample of muscle tissue the size of a 10p is removed. The sample is used for several tests on mitochondria and their genes.
Fresh Muscle Biopsy: The sample of muscle is never frozen prior to testing. This is preferable to a frozen muscle biopsy.
Frozen Muscle Biopsy: The muscle tissue is frozen before testing. If freezing is necessary, it should be done in liquid nitrogen to snap-freeze the tissue and then shipped to the laboratory on dry ice. This is not ideal because some important Mitochondrial enzymes are destroyed by the freezing process and cannot be tested in a frozen sample.
Mutation: A change in the genetic material, either in the DNA or genes.
Point Mutation: The exchange of one amino acid on the gene for another.
Point Deletion: The deletion of a single amino acid on the gene.
Pyruvate: Pyruvate is formed when sugar is broken down for energy in the presence of oxygen (aerobic metabolism).
Screening or Initial Investigations: Initial investigation tests are conducted to determine if further; more specific testing is needed. Initial investigations are also important to “rule out” some disorders (e.g. prove they are not the problem). These initial tests are carried out on blood, urine.
The Respiratory Chain Complexes:
Each complex is made up of multiple proteins. There are actually 100 proteins involved in the respiratory chain. This table lists the various names of a few of the proteins involved in each complex.
Complex I = NADH dehydrogenase complex; NADH; ubiquinone oxireductase; coenzyme Q reductase.
Complex II = Succinate dehydrogenase complex; succinate; ubiquinone oxidoreductase; coenzyme Q reductase.
Complex III = Cytochrome BC l complex; ferrocytochrome c oxidoreductase; coenzyme Q; cytochrome c reductase.
Complex IV = Cytochrome oxidase; terminal oxidase; ferrocytrochrome c; oxygen oxidoreductase; cytochrome c oxidase.
Complex V = ATP synthase
In addition to these complexes, two other electron transport complexes, DHO-QO (dihydro orotate dehydrogenase CoQ oxidoreductase) and ETF-QO (electron transport flavoprotein coQ oxidoreductase), play essential roles in energy production.