The living organisms are millions in number. They are different shapes and sizes and contain organs that also vary in shape, size and number of cells.
The scientists observe the cells and their parts under the microscope in detail by staining them with dyes. The cells of the living organisms vary in shape, number and size.
Size of the cells:
In addition to the variation in shape the cells also show a variation in size. The size of the cell may vary from a micrometer (a million of a meter) to as large as a few centimetres. Majority of the cells are microscopic in size and hence invisible to the naked eye. These cells can be seen only with a microscope.
A cell generally has a diameter of \(0.01\)mm approximately.
Bacteria is the smallest cell among the unicellular organisms. It is \(0.01 to 0.5 micrometer \)in size.
The red blood cells are the smallest cells present in the human body.
Different sizes of the cells compared with RBC's
The egg of an ostrich is the largest cell. It measures \(170 mm ×130 mm \)in size (millimeter: mm).
Comparison between Ostrich & Chicken egg
The size of the cells have no relation with the size and functioning of the animals and plants. Hence it is not necessary that the cells of the elephant to be larger than that of the mouse.
The nerve cells are an example for this as whether it is an elephant or rat the nerve cells are long, branched and perform the same function, that of transferring messages.
Structure of a neuron cell
Different types of cells based on sizes