Cell : The Unit of Life
- Cell is the structural and functional unit of all living things.
- Robert hooke (1665) used crude microscope and discovered hollow cavities (empty boxes) like compartments in a very thin slice of cork (cell wall) and named them as cellular (or) cells.
- A living cell was first described by Anton Von Leeuwenhoek.
- Robert Brown Laher named and discovered the nucleus in a cell.
- The term protoplasm was coined by J.E.Purkinje. Protoplasm is the living substance present inside the cell.
- Electron microscope was developed by Max knoll and Ernst Ruska (1931) in Germany.
- Study of living cells can't be done by electron microscope because of high voltage (50,000 - 1,00,000 Volts), which is required to operate is, as that can kill the living materials.
- German Botanist M.J. schleiden (1838) and a British zoologist T. Schwann (1839) gave the concept "all living organisms are composed of cells" and products of cells.
- The theory given by schleiden and Schwann did not explain how new cells were formed.
- Rudolf Virchow (1855) first explained that cells divide and new cells are formed from pre existing cells (Omnis cellula-e cellula).
- Viruses, Viroids and prions are exceptions to the cell theory as they are obligate parasites (sub cellular in nature).
- Cell wall, cell - discovered by Robert Hooke (Non Living). Living cell - A.V. Leeuwenhoek.
- To remember botanist & zoologist, swans are bird which are under animal kingdom, so, schwann was zoologist.
View this video for the topic from 1:00 to 8:51
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