History Of Cell Membrane :: essays research papers

In the early stages of the twentieth century, little was know around cell membranes. Until the early 1950s, the biologic cell membrane was rarely mentioned in scientific literature. It was recognised that something was probably there, but hardly anything about it was known. Considering the lack of technical equipment available a century ago, scientists such as Charles Overton and Edwin Gorter were not only exploring new territory in looking at the properties of cell membranes, but laying the way for future cell biologists. Scientists had to hold another fifty years for the discovery of the electron microscope, let exclusively seventy years for the advent of freeze fracturing techniques.Nageli and Cramer in 1855 had already suggested that biological cells are separated from their environment by a membrane possessing redundant characteristics, and in 1900 Overton performed some simple but classical experiments which proposed that cell membranes were dispassionate of lipoids (1 ). By measuring the permeability of various compounds across the membrane of a frog muscle, Overton found some interesting results. He observed that lipotropic molecules (molecules attracted to fat solvents) could easily cross this cell membrane, however larger lipoid insoluble molecules could not. He also observed that sm all in all polar molecules could soft cross the membrane. Other experiments with the likes of hen eggs suggested the presence of a lipid layer in the membrane. These results became known to biologists across the world and it was generally accredited that a semi-permeable lipid membrane surrounded some if not all cells (2).Although this was opening new doors for cell biologists, the information was widely disregarded. One coke years ago biological fact was based on what could be seen and since the proposed lipid membrane was smaller than the wavelength of visible light it could not be studied under the light microscope. Most biologists merely concerned themse lves with more than evident structures. However, some scientists continued to dedicate their time to examining this &8216invisible&8217 structure. devil such biologists were the Dutch Edwin Gorter and F. Grendel. They recognised in 1925 that two such lipid layers existed.