sejttétel

The sejttétel, or "sejtelmelet" (cell theory) in Hungarian, refers to the foundational biological concept that describes the cell as the basic structural and functional unit of all living organisms. Developed through contributions from multiple scientists in the 19th century, this theory remains one of the most important principles in modern biology.

The sejttétel consists of three core principles. First, all living organisms are composed of one or more cells. Second, the cell is the smallest unit capable of performing all vital processes, such as growth, metabolism, and reproduction. Third, all cells arise from pre-existing cells through division, a principle that refutes spontaneous generation. These ideas were refined over time, with key figures like Matthias Schleiden, Theodor Schwann, and Rudolf Virchow playing pivotal roles in its formulation.

Schleiden, a botanist, proposed in 1838 that plants were made of cells, while Schwann later extended this idea to animals in 1839. Virchow’s 1855 assertion, *omnis cellula e cellula* ("every cell originates from another cell"), solidified the third principle. Advances in microscopy and staining techniques in the 19th century provided empirical evidence supporting these claims, allowing scientists to observe cellular structures in greater detail.

The sejttétel laid the groundwork for understanding cellular biology, genetics, and molecular processes. It also influenced fields like medicine, where the study of cells—such as bacteria, cancer cells, and stem cells—has led to breakthroughs in disease treatment and diagnostics. While the theory has been expanded with discoveries in molecular biology and genetics, its core tenets remain valid and foundational to contemporary biological research.