Cell- Structure and Functions

You all might have heard of cells, right? now, what are cells basically? Cells are the basic structural, functional and biological unit of life. They perform all the life functions in a living organism.

You might have seen a building being constructed. Builders use bricks for giving shape to it. We can also see that by adding bricks one by one, a wall is constructed. By further adding walls, a room is made. So the basic unit of abuilding is the brick. The cell of an organism is also the same.

History of Cell

You might also be wondering who first saw a cell. The answer to it is Robert Hooke. He first saw a cork cell in 1664 by using a primitive microscope. (You can see it in the Picture Gallery)he saw a small box like structures very close to each other. these boxes were the dead cork cells. living cells were later observed by Anton van Leeuwenhoek by using an improved microscope.

 Theodor Schwann, Mathias Schleiden, and Rudolph Virchow were the three German biologists who in 1838, helped evolve the cell theory. the concepts of cell theory are-

All living organisms are made of cells.

The cells are the basic unit of life.

New cells arise from old cells.

Diversity in cells-

Cells are divided into two types on the basis of the number of cells-

 Unicellular Organisms-                                                                   Multicellular Organisms-

   

There is only one cell in this organism.	There is more than one a cell in this organism.
The single cell performs all the life functions.	The different cells perform specialized functions.
Examples- Amoeba, Paramecium, bacteria etc.	Example- Humans, animals, birds, etc.

 A primitive microscope used by Robert Hooke.

 Unicellular organism- Paramecium

 Multicellular organism- A human being