I stumbled on this cool video on YouTube. In an entertaining fashion it explains some of most mind-boggling things about our cells--that the mitochondria, which provides energy for the cell, likely is the vestige of an ancient bacteria that existed outside of the cell. It has its own DNA. Our mitochondria comes exclusively from our mothers. It can be traced to a single woman; hence the mitochondrial Eve. Scientists can also use it to trace human migration patterns. Enjoy the mind blowing short entertaining video.