Mitochondria are related to

A plasmid is a small circular DNA molecule found in bacteria and some other microscopic organisms.
Prions and viruses are not regarded as living things because they fall short of a few key requirements for life. For instance, they lack any cell organelles, hence they are unable to carry out any type of metabolic activity.
Although, prokaryotes lack mitochondria and instead produce their ATP on their cell surface membrane but there are many striking similarities between prokaryotes (like bacteria) and mitochondria:
1) Membranes — Mitochondria have their own cell membranes, just like a prokaryotic cell does.
2) DNA — Each mitochondrion has its own circular DNA genome, like a bacteria's genome, but much smaller.