MITOCHONDRIA

 MITOCHONDRIA

·      The mitochondria (Greek. “mitos” - thread; “chondros” - granule) are the centres for the Cellular respiration and Energy metabolism.

·       Mitochondria was first described by a German Pathologist named Richard Altmann in 1890.

·       Mitochondria are regarded as the “Power houses of the cell”.

·   Mitochondria are rod-like or filamentous bodies. It is present in eukaryotes and absent in prokaryotes.

·       The Eukaryotic cells contains 800 to 2500 Mitochondria per cell.

·       The size of the mitochondria is 0.2 to 0.8 µm in diameter and 0.5 to 1.0 µm in length.

·       The shape of the mitochondria in Non – static.

·       Major function of Mitochondria ATP Generation through Electron Transport Chain (ETC).

·       Mitochondria consist of 5 important parts. They are

a)     Outer Mitochondrial Membrane

b)     Inner Mitochondrial Membrane

c)     Inter Membrane Space

d)     Cristae

e)     Matrix

Mitochondria

a) Outer Mitochondrial Membrane

·       Outer mitochondria membrane is present in the outer surface of the Mitochondria.

·       It consist of Phospholipids and considerable amount of Cholesterol.

·      The Outer mitochondrial membrane is permeable to all molecules (<10,000 Daltons) due the presence of protein “Porin”.

b) Inner Mitochondrial Membrane

·      Inner mitochondria membrane is present in the inner surface of the mitochondria.

·      It consists of Phospholipid – Cardiolipin and rich in Proteins.

·  The Inner Mitochondrial Membrane is impermeable to polar and ionic substance. It is permeable to Pyruvate, ADP, ATP, Succinate, α – ketoglutarate, Malate, Citrate and Ions (Hydrogen, Potassium and Sodium).

·       Inner mitochondrial membrane is larger than Outer mitochondrial membrane.

c) Inter Membrane Space

·      The space between the Outer mitochondrial membrane and Inner mitochondrial membrane is called “Inner membrane space”.

d) Cristae

·   The inner mitochondrial membrane is highly folded and forms the finger like structure called “Cristae”.

e) Matrix 

·   The space inside the Inner mitochondrial membrane is called “Matrix”.

·    Matrix contains Circular DNA, Ribosomes, Granules and ATP Synthase.

·   It is rich in the enzymes responsible for the Citric acid cycle, β-oxidation of fatty acids and Oxidation of amino acids.

Functions of Mitochondria

·       ATG Generation through Electron Transport Chain.

·       Regulates the Metabolic activity of the cell.

·       Promotes the growth of new cells and cell multiplication.

·       Plays an important role in Apoptosis or Programmed cell death.

·       Helps in maintaining an adequate concentration of Calcium ions within the compartments of the cell.

·      Also involved in various cellular activities like Cellular differentiation, Cell signaling, Cell senescence, Controlling the cell cycle and also in cell growth.