- Various shapes, often cylinders 1 to 10µm long.
- Two membrane layers, each a phospholipid bilayer.
- Many special proteins embedded in membranes.
- Outer membrane smooth, inner membrane convoluted and folded.
- Creates two internal compartments, one between the membranes, the other inside inner membrane.
- Often 100's or 1000's of mitochondria per cell.
- More in cells with high metabolic demands (muscle cells).
- Site of cellular respiration (creates energy for cell).
- Respiration is extracting energy with oxygen from sugars, fats, etc.
- Energy made available to cells in the form of ATP.
History (endosymbiont theory)
- Mitochondria have their own DNA !?
- Replicate independent of the cell.
- Cell membrane, nucleus and ribosomes come from an ancestral archaeon.
- Mitochondria and chloroplasts are bacteria whose ancestors were absorbed in the Precambrian.
- Over time, the endosymbionts (internal dwellers) lost the ability for an independent life.
- Mitochondrial genome arose from a purple bacterium.
- Plastid genome arose from a cyanobacterium.