Cell theory
Contributors to cell theory
Cell theory is widely accepted theory that explain the life. There are five contributors to the cell theory:
1. Robert Hooke.
2. Anton van Leeuwenhoek.
3. Matthias Schleiden.
4. Theodor Schwann.
5. Rudolf Virchow.
In 1838, German botanist, Matthias Schleiden observed that all plants are made of different kinds of cell that form the tissues of the plant.
In 1839, British zoologist, Theodor Schwann observed different types of animal cells. He reported that cells has a thin outer layer called as ‘plasma membrane’. He also states presence of cell wall in plants which is unique character of plant cells. He give hypothesis that plants and animals are composed of cells and products of cells.
In 1855, Rudolf Virchow states that cells are divided and new cells arises from pre-existing cells.
Postulates of cell theory
The combined observation of Schleiden, Schwann and Rudolf virchow gives most accepted hypothesis that states the Cell Theory:
1. The cell is the basic structural and functional unit of life.
2. All living organisms are made up of cells.
3. All cells arise from pre-existing cells.
In 1665, Robert Hooke discovered cells under compound microscope. He observed thin cork and found honeycomb-like structure that he “cells” but those were cell walls. Therefore, he actually observed cell wall of cells. Therefore, the term cell was given by Robert Hooke.
Anton van Leeuwenhoek first saw and described live cells under microscope.
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