Basically, the cell wouldn't be able to "breathe," as the mitochondria is where the respiratory functions of the cell happens. No energy would be produced, and then the cell would stop moving and die.
Vestigial organs or parts of the body
are those that has lost its function in the course of evolution. These organs
or parts have degenerated or atrophied. It can appear as remaining small or
imperfectly developed. An example is the tiny eyes on an insect living in a
lightless cave.
