Mitochondria are very important organelles. These are present only in Eukaryotic cells. They are involved in the manufacturing and supply of energy to the cell. So it may be called power house of the cell. The size and number of mitochondria is different in different cells.
It may be vesicle, rod or filament shaped. These are bound by two membranes. The outer membrane is smooth. The inner membrane forms many infoldings, called cristae. The inner chamber is called mitochondrial matrix. The inner surface of cristae contains small knob like structure, called F1 particles. These F2 particles are suspended inside the matrix.
The mitochondrial membranes have similar composition and structure as other membranes. They are composed of lipid and proteins. The mitochondrial matrix contains a large number of enzymes, coenzymes, organic and inorganic salts. It also contain DNA and ribosomes. So mitochondria can synthesize their own proteins.
Formation of new Mitochondria
These are self-replicating organelles. It means new mitochondria are formed by the division of the old mitochondria.
Many important metabolic processes take place in mitochondria. These are Krebs cycle, aerobic respiration, fatty acid metabolism etc. Energy is released from organic food during these metabolic processes. This energy is transferred to energy rich compound ATP (adenosine tri phosphate). ATP provides energy to cell on demand and ATP is broken to ADP. This ADP absorbs energy from mitochondria and again becomes ATP.