Understanding the Mystery of Living Cells
Cell Theory
In biology, cell theory is a scientific theory which describes the properties of cells. These cells are the basic unit of structure in all organisms and also the basic unit of reproduction. With continual improvements made to microscopes over time, magnification technology advanced enough to discover cells in the 17th century. This discovery is largely attributed to Robert Hooke. Over a century later, many debates about cells began amongst scientists. Most of these debates involved the nature of cellular regeneration, and the idea of cells as a fundamental unit of life. Cell Theory was eventually formulated in 1838. This is usually credited to Matthias Schleiden and Theodor Schwann. However, other scientists like Rudolf Virchow also contributed to the theory. Cell theory has become the foundation of biology and is the most widely accepted explanation of the function of cells.
The three tenets to the cell theory are as described below:
1. All living organisms are composed of one or more cells.
2. The cell is the most basic unit of life.
3. All cells arise from pre-existing, living cells.
The timeline for arriving at this was as follows :
(click on the scientists picture to see his contribution)
Robert Hooke 1663 - 1665 The cell was discovered by Robert Hooke in 1665. He examined very thin slices of cork and saw a multitude of tiny pores that he remarked looked like the walled compartments a monk would live in. Because of this association, Hooke called them cells, the name they still bear. However, Hooke did not know their real structure or function. Hooke’s description of these cells was published in Micrographia. His cell observations gave no indication of the nucleus and other organelles found in most living cells
Anton Van Leeuwenhoek 1674 - 1683 He was inspired by the glasses used by drapers to inspect the quality of cloth. He taught himself new methods for grinding and polishing tiny lenses of great curvature which gave magnifications up to 270x diameters, the finest known at that time. These lenses led to the building of Anton Van Leeuwenhoek’s microscopes considered the first practical microscopes, and the biological discoveries for which he is famous. He looked at the pond scum and was the first to see single cells. He called them “animalcules”.
Robert Brown 1833 He was an english Botanist discovered the nucleus in plant cells.
Matthias Schleiden 1838 He stated that the different parts of the plant organism are composed of cells. Thus, Schleiden and Schwann became the first to formulate what was then an informal belief as a principle of biology equal in importance to the atomic theory of chemistry. He also recognized the importance of the cell nucleus, and sensed its connection with cell division.
Theodor Schwann 1839 Matthias Schleiden found that all plants are composed of cells, and communicated the finding to Schwann, who had found similar structures in the cells. Other researchers confirmed the similarity, as explained in his book, where he concluded, "All living things are composed of cells and cell products. This became the cell theory
Rudolph Virchow 1855 Rudolph Virchow suggested that all cells come from pre-existing cells. His aphorism’omnis cellula e cellula’ meaning every cell from a pre-existing cell became the foundations of division, even if the process was not fully understood then. He also stated that not all plants are made up of cells,which eventually lead to the creation of the cell theory
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