STRUCTURE OF MITOCHONDRIA

ORGANELLES IN A CELL
 There are several structures scattered in cytoplasm of a cell. These are called as organelles which performs different functions in cell. Mitochondria is one such organelle which is very important as it is involved in respiration of a cell. 

STRUCTURE OF MITOCHONDRIA
 Mitochondria ( singular: mitochondria) are small, spherical or cylindrical organelles. The number of mitochondria in a cell depends upon the functions it performs. Cells with heavy energy demands, such as muscle cells, have more mitochondria than other cells.
Generally a mitochondrion is 2-8 micron long and about 0.5 micron wide. It is about 150 times smaller than the nucleus. There are about 100 to 150 mitochondria in each cell. 
When seen under the compound microscope ,the mitochondria appears oval or cylindrical dots in the cell. 
When seen under the electron microscope, the mitochondria seems to have a double membrane wall. Their outer membrane is smooth whereaa inner membrane protrudes into small finger like projections called cristae, towards the inner surface. The space between the cristae is found to be filled with a fluid like substance called matrix. 
Cristae is the site for cellular respiration because it has all the enzymes which release energy from the oxidised food during respiration. 
Mitochondria are also called as power house of a cell because they are responsible for cellular respiration, a process by which cell derives its energy to do the work. 
        L.S. of a mitochondrion

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