The cell is the basic structural and functional unit of every living organism. Just as a brick wall is built from single bricks, the body is built from basic building blocks called cells. All living things are made of one or more cells, and the cell is self-sufficient to carry out all the fundamental and essential functions of an organism. Cell types vary, but they all share some common characteristic features.
1. Seeing a Cell – The Microscope
- Cells are very minute and are said to be microscopic; they cannot be seen with our naked eyes.
- They can be observed only through a specialized scientific instrument called the microscope.
- Nowadays an electron microscope is used to magnify and observe cells.
2. Discovery of the Cell – Robert Hooke
- Robert Hooke, an Englishman, was a scientist, mathematician and inventor.
- He improved the microscope used in those days and built a compound microscope.
- He placed a water-lens beside the microscope to focus the light from an oil-lamp on specimens, lighting them brightly so that he could see minute parts clearly.
- One day he made thin sections of cork and observed them through his microscope. He saw many small, identical chambers which were hexagonal in shape.
- He then observed many other objects, such as a butterfly's wings and a bee's compound eyes.
- Based on these observations, he published the book Micrographia in 1665, where he first used the term "Cell". He used the term cell to describe the structure of tissue.