2. 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 metre) to as large as a few centimetres. The majority of the cells are microscopic in size and hence invisible to the naked eye. These cells can be seen only with a microscope.

Bacteria is the smallest cell among the unicellular organisms. It is \(0.01\) to \(0.5\) micrometre in size.

 

 

The red blood cells are the smallest cells present in the human body.

 

 

The egg of an ostrich is the largest cell. It measures \(170\ mm ×130\ mm\) in size (millimetre: mm).

 

 

The size of the cells has no relation with the size and functioning of the animals and plants. Hence it is not necessary that the cells of the elephant be larger than that of the mouse.

 

The nerve cells are an example for this as to whether it is an elephant or rat; the nerve cells are long, branched and perform the same function, that of transferring messages.

 

 

Different types of cells based on sizes