The powerhouse - mitochondria

Mitochondria provides chemical energy for the cell to perform its functions.
It is membrane bound organelle and is 0.5-2.0micrometer seen under electron microscope .

Mitochondria is a site for : 1. Citric acid cycle(a.k.as Kreb's cycle)
                                            2. Electron transport pathway and
                                            3. Oxidative phosphorylation
remember ... citric acid cycle takes place in mitochondrial matrix while later 2 reactions are in the inner mitochondrial membrane.
                                           4.Urea cycle only in hepatocytes

Mitochondria produces reactive oxygen species and oxidant stress .it also play a role in activation of apoptosis.

You know the cell which is without the powerhouse in it !!  they survive using glycolysis for energy. Which is that unique !!!!!

  The cell with no mitochondria is – RBC.

Structure of MITOCHONDRIA:

It has 2 membranes :  outer and inner membrane .

This is separated by the intermembrane space.

The lumen of the mitochondria has the mitochondrial matrix and is surrounded by the inner membrane.

Inside the lumen the inner membrane has tubular invaginations called cristae. The number of cristae differs with the type of the cells.

NOTE :

Outer membrane --- free permeability present, as porins are present on them.

(Porins are large non-specific channels)

Inner membrane ---- relatively impermeable, due to presence of cardiolipin (is a phospholipid).

INTERESTING FACT ON MITOCHONDRIA : Your mitochondria are definitely from your Mom.

All mitochondria we have in all types of cells ( except RBC) are derived from previously existing ones  i.e all are descended from the cytoplasm of the fertilized ovum.

During fertilization, mitochondria of the sperm are not generally incorporated into the ovum .Therefore MITOCHONDRIA ARE PASSED ONLY THROUGH FEMALE LINE (maternal origin).