Cell: Fundamental Unit of Life

By Ajay Anand


The basic structural unit of a living organism is called cell. All living beings are made up of cells.

Discovery of Cell

Robert Hooke coined the term cell in 1665.

Hooke's Microscope

Robert Hooke used a self-made microscope to observe cells.

Cork Cell

Robert Hooke observed cells in a thin slice of cork. This figure shows how he saw those cells.

Cell Theory

Schwann Schleiden & Virchow

The cell is the basic structural and functional unit of life. All organisms are composed of cells.

All cells are produced by the division of preexisting cells.

All basic chemical and physiological functions are carried out by cells.

Variety in Number

Living beings show a large variation in number of cells.

Large organisms; like humans, elephants, tiger, etc. are made up of trillions of cells. They are called multicellular

But small organisms, like amoeba and bacteria are made up of single cell. They are called unicellular

Variation in Shape

Cells show wide variations in terms of shape.

Cells can be round, cylindrical, spindle-shaped, star-shaped, irregular, etc.

Shape of Cells

White Blood CellsIrregular
RBCsRound and Concave
Striated MuscleCylindrical
Nerve CellStar with a tail
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