Cell FOR BPSC
Cell – The Unit of Life
Introduc on
Cell is the structural and func onal unit of life.
All living organisms are made up of cells.
Organisms can be:
o Unicellular (e.g., Amoeba, Paramecium)
o Mul cellular (e.g., Humans, Plants)
Discovery of Cell
Robert Hooke (1665): Observed cork under a microscope; coined the term “cell”.
Anton van Leeuwenhoek (1674): First observed living cells (bacteria and protozoa).
Cell Theory
Proposed by:
o Ma hias Schleiden (1838) – studied plant ssues.
o Theodor Schwann (1839) – studied animal ssues.
Postulate: All living organisms are composed of cells and cell products.
Rudolf Virchow (1855) added: “Omnis cellula e cellula” – cells arise from pre-exis ng
cells.
Types of Cells
Prokaryo c Cells
Simpler, smaller, lack membrane-bound organelles.
Cell – The Unit of Life
Introduc on
Cell is the structural and func onal unit of life.
All living organisms are made up of cells.
Organisms can be:
o Unicellular (e.g., Amoeba, Paramecium)
o Mul cellular (e.g., Humans, Plants)
Discovery of Cell
Robert Hooke (1665): Observed cork under a microscope; coined the term “cell”.
Anton van Leeuwenhoek (1674): First observed living cells (bacteria and protozoa).
Cell Theory
Proposed by:
o Ma hias Schleiden (1838) – studied plant ssues.
o Theodor Schwann (1839) – studied animal ssues.
Postulate: All living organisms are composed of cells and cell products.
Rudolf Virchow (1855) added: “Omnis cellula e cellula” – cells arise from pre-exis ng
cells.
Types of Cells
Prokaryo c Cells
Simpler, smaller, lack membrane-bound organelles.
