Cell : The Unit of Life

Cell theory


  • 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).
  • Virues, 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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