cell theory

• what is a prokaryote cell (bacteria)


  single celled organism, no nucleus or membrane bound organelles
• what is a eukaryote cell

  made up multi-cellular organisms such as plants and animals
• all living things are composed of cells and cell products
• new cells formed by division of existing cells
• cell contains genes which is used as instructions for growth, functioning and development
• 1665 cells


  robert hooke first described cells
• 1674-1683


  first living cell observed
• 1674-1683


  anton van leeuwenhoek first person to observe bacteria from pond water samples, after developing glass lenses
• 1891


  nucleus observed, robert brown (botanist) first to observe and describe nucleus in plant cell
• 1674-1683 universal cell theory


  matthias schleiden suggested that all plant material is composed of cells.
• 1674-1683 universal cell theory


  Jan Purkyne observed that animal tissue is composed of cells and structure is similar to plant tissue, the scientist credited for universal cell theory is Theodor Schwann, german physiologist, proposed all living things are made of cells
• 1852 evidence for the origin of new cells

  Robert Remak observed cell division in animal cells. his findings were not accepted at time, in 1855 Rudolf Virchow published findings as his own to show new cells form from existing ones
• 1860 spontaneous generation disproved

  Louis Pasteur demonstrated that bacteria will only grow in sterile nutrient broth after it has been exposed to air, disproved the theory of spontaneous generation of cells