Many people have puzzled about the origins of mitochondria. They look very similar to some types of bacteria and are enclosed by their own double lipid membrane. They also have remnants of their own DNA. Scientists have a theory that mitochondria were once free living bacteria that specialised in producing energy. Larger cells that may have taken them into their cytoplasm, hoping to digest them for food, perhaps got used to the extra energy supply they provided and put off digestion for a while.
These cells may have survived longer and evolved to live in a symbiotic relationship with the power-producing bacteria that they had engulfed.
After probably millions of years, the mitochondria became unable to live independently as bacteria and now are part of the structure of modern cells. It is a strange thing, but mitochondria are only ever passed on from your mother ~ in the cytoplasm of the fertilised egg. The DNA of mitochondria can be used to trace female descent back to tribes of nomadic humans that lived hundreds of thousands of years ago.
These cells may have survived longer and evolved to live in a symbiotic relationship with the power-producing bacteria that they had engulfed.
After probably millions of years, the mitochondria became unable to live independently as bacteria and now are part of the structure of modern cells. It is a strange thing, but mitochondria are only ever passed on from your mother ~ in the cytoplasm of the fertilised egg. The DNA of mitochondria can be used to trace female descent back to tribes of nomadic humans that lived hundreds of thousands of years ago.
