DNA, or deoxyribonucleic acid, is found in the nucleus of a cell. Also, a small amount of DNA known as mitochondrial DNA, or mtDNA, is found in the mitochondria of the cell because the 37 genes found in mtDNA are necessary for the mitochondria to function. Every living creature has unique DNA that contains its biological instructions.
Each human is comprised of not millions, but trillions of cells. Each cell has its own nucleus that holds a copy of the DNA for that individual. The nucleus of the cell is similar to the cockpit of an airplane; t is the command center where everything happens. Any action the cells take, whether that be to grow or replicate, begins in the nucleus. It is also the place where DNA is stored safely away. In order to protect the DNA, a membrane known as the nuclear envelope surrounds the DNA in the nucleus to separate it from the rest of the cell.
The mitochondria of a cell where mtDNA is found creates enzymes and molecules like RNA and tRNA, which are involved in making amino acids. Without the mtDNA, the mitochondria could not function because the instructions to create these enzymes and molecules is housed in the mtDNA.