Cell theory

The cell theory is one of the fundamental insights in the field of biology. It says that all plants and animals and their organs, as varied as they may be, are always composed of cells. This theory zeitigte far-reaching conclusions: Growth is a process in which more and more cells are formed, which always re-emerge from cells. Even in reproduction, the cell plays the essential role. New individuals are always formed from living cells through cell division, can never be a spontaneous generation, so the emergence of cells from dead material, are observed. The findings of the cell theory eventually led to a principle of biology, was formulated in Latin as: omnis cellula e cellula ( every cell comes from a cell).

History of cell theory

The development of the cell theory is closely linked with the history of cell biology (cytology ). According to the invention, optical devices such as microscope, the fine structure of the anatomical plants was examined. 1665 Robert Hooke coined the term as the first cell ( cellula, little room ), after he had observed this in the tissue of the cork, and he later found in other plant -like structures.

In his textbook Phytotomie 1830 described the physician and botanist Franz Julius Ferdinand Meyen the microscopic structure of plant organs from cells. In the same year Karl Heinrich Baumgartner published his education sphere theory, which is also considered as a precursor of the cell theory.

The cell theory was first formulated in 1838 by Matthias Schleiden for the plants. That same year, Theodor Schwann extended this statement on animal organisms. The essential commonality of all living things was identified with it. These observations were " Microscopic Investigations on the Accordance in the Structure and Growth of Animals and Plants" summarized in Schwann and published in 1839. Schwann formulated the basic principles of embryology by observing that an egg is a single cell that eventually develops into a complete organism.

The theory was extended in the 1850s by the Berlin physician Rudolf Virchow for medicine. 1858 Virchow published his theory of cellular pathology, which says that diseases are based on disturbances of the body's cells. This realization is one of the pillars of today's pathology. The influence of microorganisms on the development of diseases played for Virchow but still no role.

Through the work of Louis Pasteur, the possibility of spontaneous generation ( spontaneous generation ) has been definitively excluded.

Key messages

The now generally accepted statements of the cell theory hold:

• All organisms are composed of one or more cells.
• Cells always arise from other cells through cell division.
• All cells have the same structure in their ground plan and biochemically substantially.
• The cell is the basic unit of the structure and function of the organisms.
• The basic metabolism takes place within the cells.
• Genetic material and genetic information passed on during cell division.

• Cell Biology