Cell Theory Lesson - General Biology 1

Cell Theory General Biology 1: Lesson 1  In1665, British scientist Robert Hooke discovered cells  He examined a piece of cork and found little structure in which he compared to cellulae (‘little rooms”) Cell Theory  Developed in the mid-1800s  Is one of the basic principles of bi...

Cell Theory General Biology 1: Lesson 1  In1665, British scientist Robert Hooke discovered cells  He examined a piece of cork and found little structure in which he compared to cellulae (‘little rooms”) Cell Theory  Developed in the mid-1800s  Is one of the basic principles of biology  Cell Theory First Postulate: The cell is the basic unit of life In order that an organism may be considered living, it must have a cell. Unicellular or one- celled, such as bacteria. Multicellular or multi- celled, such as animals one proof that an organism is alive just by looking at its cell is the movement of the organelles inside it. When the protoplasm of the cell had dissipated it indicates the cell’s death (Hooke) When the animalcules in teeth scrapings are shooting and spinning inside the cell means it contained live bacteria (Leeuwenhoek.)  Cell Theory Second Postulate: All living organisms are composed of cells This declaration was a collaboration between a botanist and physiologist. Matthias Jacob Schleiden (German Botanist) a lawyer in practice turned botanist recognized Robert Brown’s discovery of nucleus in 1833. He established that the small compartments in his plant specimens are cells (1838) Teodor Schwann (German Physiologist) correlated his results with those of Schleiden’s. He then instituted that all animals also composed of cells  Cell Theory Third Postulate: New cells are create from preexisting cells This elucidates that cells can only be formed by the union of male and female cells, or the division of a single cell. It disapproved the archaic theory of spontaneous generation, which promoted the concept that living things generated from non- living things.  Development of Cell Theory 1590 Zacharias Janssen (Dutch spectacle- maker) invented a primitive microscope with the help of his father, Hans 1663-1665 Robert Hooke viewed a thin slice of cork where he found hollow, small structures which reminded him of cellulae used by monks. “Cells” 1665-1676 Marcello Malpighi (Italian scientist) and Nehemiah Grew (English botanist) 1670 – Anton Van Leeuwenhoek upgraded 1683 Janssen’s microscope and produced his own lens and some could magnify objects up to 270x diameters. With this he discovered mobile organelles, which he Development of Cell Theory 1831 Robert Brown (Scottish botanist) discovered the nucleus. This became a major breakthough in the history of biology 1838 Matthias Schleiden, he wrote Contributions to Phytogenesis, he proposed that the different structures of a plant are all composed of cells 1839 Theodor Schwann declared that animals are different likewise composed of cells. This put an end to the debates-whether or not plants and animals are different in structural origin and composition. 1840 Albrecht von Roelliker (Swiss embryologist) stated that sperm and egg are composed of cells. This initiated the Development of Cell Theory 1849 Louis Pasteur (French microbiologist) was developing fermentation, a process to kill bacteria, he also proved that bacteria are able to multiply and that bacteria’s cells come form other bacterial cells 1858 Rudolf Virchow declared, “Omnis Cellula e cellula,” which meant that cells come from preexisting cells.