Cell Theory In 1838,was proposed by Jakob Matthias Schleiden(1804-1881) was a German botanist and Theodor Schwann (1810-1882) was German zoologist.
Scheilden said that-:All plants consists of cell
Schwann said that-:All animals and plants are made up of cells
Cell Theory was refined by R.Virchow.He presented the idea that-:All cells are arise from pre existing cells only.
Thus,Cell Theory's postulates are:_
1-All organisms are composed of cells and cell products.
2-All metabolic reactions takes place in cells.Thus,cell are structural and functional unit of life.
3-All cells are arise from pre existing cells only.
4-Every organism starts its life with single cell only.Viruses are exceptions.
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