Mitochondria contain their own DNA, called mtDNA, in the form of small circular molecules that evolved from the circular genomes of the bacterial ancestors from which mitochondria descended. The mtDNA of different organisms varies in size from 11 kb in some animals to 1000 kb in some fungi, plants and protists.
Mitochondria, often referred to as the “powerhouses of the cell”, were first discovered in 1857 by physiologist Albert von Kolliker, and later coined “bioblasts” (life germs) by Richard Altman in 1886. The organelles were then renamed “mitochondria” by Carl Benda twelve years later.