Mitochondrion
Mitochondrion is the singular form of mitochondria. The mitochondria
major role is ATP production in the eukaryotic cell. These are mobile
and flexible organelles, although in some cells they tend to stay in
a fixed position. The fixed position is especially true of cells or locations
in cells where there will be a need for a high amount of ATP production, such
as, near flagella or between myofibrils of muscle.
Mitochondria are also self-reproducing, they have their own circular DNA,
with a slightly modified version of the codons.
This differs with the eukaryote codon table.