Mitochondria

The mitochondrion is a membrane-bound organelle found in most eukaryotic cells.
Several characteristics make mitochondria unique. The number of mitochondria in a cell varies widelyby organism and tissue type. Many cells have only a single mitochondrion, whereas others can contain several thousand mitochondria. The organelle is composed of compartments that carry out specialized functions. Thesecompartments or regions include the outer membrane, the intermembrane space, the inner membrane, and the cristae and matrix. Mitochondrial proteins vary depending on the tissue and thespecies. Although most of a cell'sDNA is contained in the cell nucleus, the mitochondrion has its own independent genome.
Richard Altmann, in 1894, called them "bioblasts".
The term ‘mitochondria’ was applied byCarl Benda (1897-98)
Lewis and Lewis (1914) made extensive study of mitochondria in living cells, emphasizing their sensitivity to metabolic conditions.
In 1939, experiments using minced musclecells demonstrated that one oxygen atom can form two adenosine triphosphate molecules
Presence of DNA molecule in the mitochondria was observed by Margit M. K. Nass and Sylvan Nass in 1963.
Thepopular term "powerhouse of the cell" was coined by Philip Siekevitz in 1957
In 1967, discovered ribosomes in the mitochondria
There are two hypotheses about the origin of mitochondria: endosymbiotic andautogenous. The endosymbiotic hypothesis suggests mitochondria were originally prokaryotic cells, capable of implementing oxidative mechanisms that were not possible to eukaryotic cells; theybecame endosymbionts living inside the eukaryote. In the autogenous hypothesis, mitochondria were born by splitting off a portion of DNA from the nucleus of the eukaryotic cell at the time of divergence withthe prokaryotes; this DNA portion would have been enclosed by membranes, which could not be crossed by proteins.
Damage and subsequent dysfunction in mitochondria is an important factor in a...