Medical Definition of Mitochondria

  • Medical Author:
    William C. Shiel Jr., MD, FACP, FACR

    Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

Mitochondria: Structures located in the cell's cytoplasm outside the nucleus. Mitochondria are responsible for energy production. Each consists of two sets of membranes: a smooth, continuous outer coat and an inner membrane arranged in tubules or in folds that form plate-like double membranes (cristae). The mitochrondria are the principal energy source of the cell. They not only convert nutrients into energy but also perform many other specialized tasks. Each mitochondrion has a chromosome that is made of DNA but is otherwise quite different from the better-known chromosomes in the nucleus. The mitochondrial chromosome is much smaller than other chromosomes. It is round, whereas the chromosomes in the nucleus are shaped like rods. There are many copies of the mitochondrial chromosome in every cell, whereas there is normally only one set of chromosomes in the nucleus. All mitochondrial chromosomes are inherited from the mother.

Reviewed on 12/12/2018


Heart Disease: Causes of a Heart Attack See Slideshow

REFERENCE: NIH, US Library of Medicine, Genetics Home Reference. Mitochondrial DNA.

Health Solutions From Our Sponsors