Explain Size of Cells

The size of the cell is microscopic. It cannot be seen through naked eyes. The size of an ultramicroscopic cell ranges between 10 to 100 micrometer ( m) (1 m = 1/1000 mm). The smallest known cell is Pleuro-pneumonia like organism (PPLO). Its size ranges between 0.1 to 0.5 mm. Ostrich egg is the largest known animal cell. Its size measures 170 135 mm. In plant kingdom the algae cells exhibit very large size. A single cell of algae Acetabularia is about 10 cms. long. In human beings the nerve cells are the largest in size. Sometimes the nerve cells measure about 1 meter in length. The muscle cells are also big in size. The cells of liver, kidney and intestine have diameters ranging between 20 to 30 micrometer.
Size of the cells usually effects their functional activity. Smaller cells possess more surface area than bigger cells. Because of this the smaller cells can quickly exchange the substances with their environment. There is no relation between the size of the cells and the size of the organisms. e.g. The cells of the giant animals like elephant and whale are not big in size but the tissue has the cells of the proper size in accordance with its function.