When an X-ray beam strikes the chemical molecule under investigation, its rays diffract, or bend, as they pass through it. The interference patterns of the diffracted X rays are recorded on film, where they show up as dark patches. Once the structure of DNA was understood, biophysicists were able to uncover many of the mechanisms of heredity. The Biophysics of Cell Membranes Biophysical analyses of cells, tissues, and organs rely on the electron microscope and the techniques of surface chemistry and birefringence, or double refraction. These techniques are helpful in the study of the membranes that enclose cells.
Surface chemistry explores the forces at work on membrane edges.
Birefringence can pinpoint the presence of certain chemicals in both the membrane and the cell by the way in which light is doubly refracted through them. Cell membranes are essential for the life of a cell. They determine what gets in and out of it. Cell membranes are only about one hundred angstroms thick. They consist of lipids and proteins organized as tiny leaflets, two molecules thick, or as tightly packed globules.