Plus one Biology lecture for NEET UG in malayalam.
Cell : The Unit Of Life (Chapter 8)
NEET Master Malayalam.
Mitochondria (sing.: mitochondrion), unless specifically stained, are not
easily visible under the microscope. The number of mitochondria per cell
is variable depending on the physiological activity of the cells. In terms of
shape and size also, considerable degree of variability is observed. Typically
it is sausage-shaped or cylindrical having a diameter of 0.2-1.0µm (average
0.5µm) and length 1.0-4.1µm. Each mitochondrion is a double
membrane-bound structure with the outer membrane and the inner membrane dividing its lumen distinctly into two aqueous compartments,
i.e., the outer compartment and the inner compartment. The inner
compartment is called the matrix. The outer membrane forms the
continuous limiting boundary of the organelle. The inner membrane forms
a number of infoldings called the cristae (sing.: crista) towards the matrix
(Figure 8.7). The cristae increase the surface area. The two membranes
have their own specific enzymes associated with the mitochondrial
function. Mitochondria are the sites of aerobic respiration. They produce
cellular energy in the form of ATP, hence they are called ‘power houses’ of
the cell. The matrix also possesses single circular DNA molecule, a few
RNA molecules, ribosomes (70S) and the components required for the
synthesis of proteins. The mitochondria divide by fission.