Question

If a cell is the main structural and functional unit of an organism, why is it so small? And why are there no organisms with huge cells?

Answer 1

Dear student.

A unicellular organism is made up of a single small cell that can perform all the necessary functions. Higher organisms like human are made up of several small cells that perform every function required for life. To maintain a compact large multicellular structure like human it is much more necessary to maintain the proper functional balance of different cells rather than size. The size of the cells also matters here. With small size, cells can be transported easily (blood cells), small size requires lesser amount of energy and more over if the cells become too large plasma membrane may lose its elasticity thus hard to maintain cellular activities.

Regards.