Where did mitochondria come from?,

We know that mitochondria were originally an integral part of the cell, evidence from bacteria. They still contain a tiny amount of DNA that is similar to bacterial DNA. About 1,500,000,000 years ago, a bacterial cell was engulfed by another cell, but rather than killing each other, the two cells worked together, probably because it was beneficial to each cell. Nuclear DNA determines our physical characteristics, mitochondria DNA does not. Mitochondria has its own independent genome, are passed to offspring only inherit from the mother. This is mean when a sperm fertilize an egg, they only pass on the DNA from their nucleus, not their mitochondria. The embryo has all its mitochondria from the mother’s egg.