Home Preparation for National Talent Search Examination (NTSE)/ Olympiad
Chapter : 1. The cell
Cell Size & Cell Shape
Cell Size : The size of different cells ranges between broad limits. Some plants and animals cells are visible to the naked eye. Most cells are visible only with microscope. The prokaryotic cells usually range between 1 to 10 µm. The eukaryotic cells usually range between 10 to 100 µm. Amoeba proteus may reach a diameter of 0.5 mm. The smallest cells are those of Mycoplasma laidlawiil (0.1µ in dimeter) or PPLO (pleuro pneumonia like organism). The largest cell is egg of an Ostrich. Cell Shape :
The shape of cell may be variable or fixed. Variable shape occur in Amoeba, WBC etc. Fixed shape occur in most plant and animals. Cells may be diverse shapes such as polyhedral (8, 12 or 14 sides) spherical (e.g. eggs of mainly animals), spindle shaped (Smooth muscle fibres), elongated (e.g. Nerves cells) so on.