Besides the nucleus, the organelle that contains DNA is the mitochondrion. Mitochondria are often referred to as the powerhouse of the cell because they generate most of the cell’s supply of adenosine triphosphate (ATP), which is used as a source of chemical energy.
Mitochondria have their own circular DNA, similar to bacterial DNA, which is distinct from the linear DNA found in the nucleus. This mitochondrial DNA (mtDNA) is inherited maternally and is crucial for the proper functioning of the mitochondria, as it provides the necessary instructions for making proteins involved in energy production.
In summary, while the nucleus is the primary repository of genetic information in eukaryotic cells, mitochondria play a significant role in cellular metabolism and also contain their own genetic material.