Every machine needs some source of energy. Whether it’s a battery, engine or a plug, energy is converted to some usable form. The body is not different. It won’t surprise you to know that food is our energy source, but it’s at the molecular level that we use food. For our cells to get that energy, they have small engines called mitochondria. The mitochondria convert food molecules into usable energy for the cell, called ATP. In each cell there are many mitochondria.

Mitochondria are called organelles, but there are many other organelles inside our cells. Its like how a body has organs, cells have organelles, each with a special function. The thing that is very special about mitochondria, is that it’s the only organelle with its own DNA, separate from the rest of our DNA. The nucleus is where our 23 chromosomes, including the X and the Y chromosomes are located. So in addition to all that nuclear DNA, we have mitochondrial DNA. mutations in Mitochondrial DNA can also cause diseases, just like mutations in the nuclear DNA. Another interesting thing is that we get all our mitochondria from our mothers. No mitochondria are inherited from the sperm, but the egg is filled with them, so by looking at our mitochondrial DNA we can trace out maternal lineage.