The mitochondrion is a double membrane bound organelle. It is found in most Eukaryotic organisms. Mature blood cells do not have them. Other unicellular organisms like microsporidia have reduced or transformed their mitochondria into another structure. Only one Eukaryote is known to have lost its mitochondria, the monocercomonoides.

Mitos in Greek means thread and chondrion means grain-like. The mitochondria generates most of the cell's ATP which are the energy currency in the cell. The mitochondria are in the cytoplasm. In addition to energy production the mitochondria are also involved in other tasks like signalling, cellular differentiation, cell death, maintaining the control over cell cycle and growth, programed cell death-apoptosis, and immune response.

Mitochondria have been implicated in human diseases, mitochondrial disorders, cardiac dysfunction heart failure and autism. The number of mitochondria in a cell can vary by organism, tissue and cell type. Red blood cells (mature) do not have mitochondria where as liver cells have more than 2000 per cell. This organelle is composed of compartments that carry out specialized functions. I nthe mitochondrion there is the outer membrane, intermembrane, inner membrane, cristae and matrix. The origin of mitochondria- the endosymbiosis theory. They descended from specialized bacteria that survived endocytosis by another species, or other cell type and became incorporated into the cytoplasm.

Bacteria, mitochondria and chloroplasts have similarities. They have their own DNA which is separate from the DNA in the nucleus. They use their DNA to produce many proteins and enzymes required for their function. They are cells on their own right. Mitochondria contain: DNA, nucleotides, ribosomes, which are distinctly unique from their parent cell. During this session we also reviewed the other organelles present in the cell.