Mitochondria are clearly visible only when stained.
Number, shape and size of mitochondria per cell are variable depending on the physiological activity.
It is sausage-shaped or cylindrical having a diameter of 0.2-1.0 μm (average 0.5 μm) and length 1.0-4.1 μm.
A mitochondrion is a double membrane-bound structure with the outer membrane and the inner membrane. It divides lumen into 2 aqueous compartments, i.e., the outer compartment and the inner compartment (matrix).
Inner membrane forms a number of infoldings (cristae) towards the matrix. They increase the surface area.
The two membranes have their own specific enzymes associated with the mitochondrial function.
Matrix possesses a circular DNA, a few RNA molecules, ribosomes (70S) and components for protein synthesis.
The mitochondria divide by fission.
Function
Mitochondria are the sites of aerobic respiration.
They produce energy in the form of ATP. So they are called ‘power houses’ of the cell.
