Cell

• Discovery of the cell

  Matthias Jakob Schleiden, a professor of botany in Germany, stated that all plants are composed of cells
• Theodor Schwann


  A professor of physiology at the University of Belgium, he studied several slides of animal tissues and stated that animals are composed of cells
• Postulates of cell theory

  • All organisms are made up of cells
  • The basic unit of life is cell
  • All cells come from pre-existing cells
• Rudolf Ludwig Karl Virchow

  postulated the idea of Omnis cellula e cellula(All cells come from cells)

• Theory of Spontaneous Generation


  Organisms came from non-living things
• Francesco Redi


  • Disproved the theory that maggots could be spontaneously generated from meat using a controlled experiment
• John Needham


  • Believed that life can arise spontaneously
  • Repeated Redi's experiment but yielded different result because he was not successful in killing all microbes while boiling broth
• Lazzaro Spallanzani


  • Disagreed to the theory of spontaneous generation after observing absence of small organisms in some chicken broth placed in sealed flasks heated for 30 minutes
• Louis Pasteur


  • Disproved spontaneous generation through an experiment where beef broth was sterilized through boiling in two flasks, one that was exposed to air and another that was protected from it