Mitochondrial DNA. Computer artwork of the genetic material (DNA, deoxyribonucleic acid) found in the cell structures called mitochondria. Mitochondrial DNA is circular in shape, more like a bacterial plasmid than the spiral shape of human DNA. It has the four nucleotide bases common to all DNA, and these bases (coloured) pair up to hold the strands together. Mitochondria drive the metabolism of a cell, allowing the reactions that provide energy for the cell. Because they have their own DNA, it is thought that they were once independent micro- organisms that were incorporated into cells in the early evolution of life. Most mitochondrial DNA is inherited from the mother.