Following on, Theodor Schwann (1810-1882)observed that all animals were composed of cells.In 1838, Theodor Schwann and Matthias Schleiden were enjoying after - dinnercoffee and talking about their studies on cells. It has been suggested that when Schwann heard Schleiden describe plant cells with nuclei, he was struck by the similarityof these plant cells to cells he had observed in animal tissues. The two scientists went immediately to Schwann's lab to lookat his slides. He summarized his observations into three conclusions about cells: The cell is the unit of structure, physiology, and organization in living things. The cell retains a dual existence as a distinct entity and a building block in the constructionof organisms. Cells form by free - cell formation, similar to the formation of crystals(spontaneous generation).
In the continuing years, French chemist and Biologist, Louis Pasteur (1822-1895) became a scientific giant, laying the foundation for several branches of science. During Pasteur’s time, there was great controversy over the theory of “spontaneous generation” – which believed that things such as beetles, eels, maggots and microbes arise spontaneously from decomposing matter. Pasteur conducted a series of clever experiments that destroyed every argument supporting “spontaneous generation”. It was through these experiments that Pasteur proved that all life comes from pre-existing life, through this Pasteur invented a new theory: The Germ Theory, which states that micro-organisms cause decaying matter and he showed that you could kill the micro-organisms by applying heat. Pasteur then followed by establishing the links between bacteria and diseases and his career continued with developing vaccines for many infectious diseases such as Anthrax and Rabies. Louis Pasteur could be deemed one of the greatest benefactors of humanity due to his numerous contributions.
After Anton Van Leeuwenhoek’s first look into microbiology, in 1986 Germany Physicist Ernst Ruska won a Noble Prize from Physics for designing the first electron microscope. Many years later he set out to design an electron microscope that allowed for much higher resolution. In 1932 he built the first crude prototype alongside Max Knoll (under whom Ruska obtained his doctorate). Despite the fact that it was primitive and not fit for practical use, the instrument was still capable of magnifying object 400 times, producing images in far greater detail than optical microscopes.
The Cell Theory:
The Cell Theory is composed of 5 Main Ideas.
-
All living things are composed of one of more cells
-
The cell is the basic unit of organisation of organisms
-
All cells come from pre-existing cells
-
Cells contain hereditary information which is passed from one cell to another through division
-
Energy flow occurs within cells
The big exceptions to cell theory are viruses. These do contain cells however they are not alive because they are not able to grow or reproduce outside of a host cell.
