Gabriela A. Hernandez
Mrs.Ayub
IB Biology
29 October 2017
Falsification of the Davson-Danielli Model of the cell membrane Since the discovery of the cell, the scientific community has been fascinated by its various structures and functions. One of the most important structures being the cell membrane, which after being discovered in 1855, played a key role in research regarding cell membranes. After the discovery its discovery , many scientists put out data regarding the cell membrane. Their research was compiled my Davson and Danielli so that the could create a model that proved that globular proteins surrounded both outer surfaces. However due to advances in the scientific their model would be proven false. In 1935 Hugh Davson and James Danielli created a model of the cell membrane. This model not only culminated the work of previous scientist but included Davson and Danielli’s own work. This model displayed a bilayer of phospholipids in the center of the membrane with globular proteins coating both of the outer surfaces. …show more content…
To being with, Freeze-fracture electron micrographs showed that globular proteins were indeed present in the center of the phospholipid bilayer, which were not accounted for in the model. Furthermore, evidence from cell fusion experiments, which tagged membrane proteins with different fluorescent markers, showed that proteins could move within the cell because the colors became mixed within a few minutes of cell fusion. Additionally, a thorough analysis of the membrane proteins showed that parts of their surfaces were hydrophobic, so that they would be positioned in the bilayer and in some cases would extend from one side to another. This evidence disproved the Davson and Danielli model and while the model was incorrect it did in fact help create the Singer-Nicolson model in 1972, which is still used
Mrs.Ayub
IB Biology
29 October 2017
Falsification of the Davson-Danielli Model of the cell membrane Since the discovery of the cell, the scientific community has been fascinated by its various structures and functions. One of the most important structures being the cell membrane, which after being discovered in 1855, played a key role in research regarding cell membranes. After the discovery its discovery , many scientists put out data regarding the cell membrane. Their research was compiled my Davson and Danielli so that the could create a model that proved that globular proteins surrounded both outer surfaces. However due to advances in the scientific their model would be proven false. In 1935 Hugh Davson and James Danielli created a model of the cell membrane. This model not only culminated the work of previous scientist but included Davson and Danielli’s own work. This model displayed a bilayer of phospholipids in the center of the membrane with globular proteins coating both of the outer surfaces. …show more content…
To being with, Freeze-fracture electron micrographs showed that globular proteins were indeed present in the center of the phospholipid bilayer, which were not accounted for in the model. Furthermore, evidence from cell fusion experiments, which tagged membrane proteins with different fluorescent markers, showed that proteins could move within the cell because the colors became mixed within a few minutes of cell fusion. Additionally, a thorough analysis of the membrane proteins showed that parts of their surfaces were hydrophobic, so that they would be positioned in the bilayer and in some cases would extend from one side to another. This evidence disproved the Davson and Danielli model and while the model was incorrect it did in fact help create the Singer-Nicolson model in 1972, which is still used