Mitochondria is the structure that only found in eukaryotic cells. It involved in energy metabolism, have more than one membrane, contain DNA and ribosomes and independent of the endomembrane system.
Prokaryotic cells are less structured than eukaryotic cells. They have no nucleus; instead their genetic material is free-floating within the cell. They also lack the many membrane-bound organelles found in eukaryotic cells. Thus, prokaryotes have no mitochondria only eukaryotic cells.