The initial idea of cell theory was given by a French biologist Dutrochet (1824). According to him, the concept that cell is the basic unit of living beings is known as the Cell theory.
The credit of formulation of cell theory is given to a German botanist M.J. Schleiden and a German zoologist T. Schwann who clearly outline the basic features of cell theory that the cell is the basic unit of life.
Modern Cell Theory ;- In 1858, Rudolph Virchow stated, "Omnis cellula-e-cellula" i.e all living cells arise from pre-existing cells. The old theory was thus revised and the modern cell theory proposed as follows :
1) All living organisms are made up of cells.
2) A cell is a small mass of protoplasm containing a nucleus or nuclear material and some organelles, bounded by cell membrane.
3) Cells always arise from the pre- existing cells by division.
4) Every organism starts its life from a single cell.
5) The growth of an organism is due to the growth of the cells or due to cell multiplication.
6) All cells are fundamentally similar.
7) All activities of the organism are sum total of activities of different cells.
8) The cells have complete genetic information in genetic material called DNA.
Viruses do not fit in the definition of cell. They don't have their own cellular machinery. they will act like a living cells only by using host cell mechinery or start to behave like a living organism. So outside the living cell Viruses are non-living and inside the body of living organism or cell they are living and starts to multiply.
The credit of formulation of cell theory is given to a German botanist M.J. Schleiden and a German zoologist T. Schwann who clearly outline the basic features of cell theory that the cell is the basic unit of life.
Modern Cell Theory ;- In 1858, Rudolph Virchow stated, "Omnis cellula-e-cellula" i.e all living cells arise from pre-existing cells. The old theory was thus revised and the modern cell theory proposed as follows :
1) All living organisms are made up of cells.
2) A cell is a small mass of protoplasm containing a nucleus or nuclear material and some organelles, bounded by cell membrane.
3) Cells always arise from the pre- existing cells by division.
4) Every organism starts its life from a single cell.
5) The growth of an organism is due to the growth of the cells or due to cell multiplication.
6) All cells are fundamentally similar.
7) All activities of the organism are sum total of activities of different cells.
8) The cells have complete genetic information in genetic material called DNA.
Viruses do not fit in the definition of cell. They don't have their own cellular machinery. they will act like a living cells only by using host cell mechinery or start to behave like a living organism. So outside the living cell Viruses are non-living and inside the body of living organism or cell they are living and starts to multiply.
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