Singer studied phospholipid bilayers and found that they can form a flattened surface on water, with no requirement for a protein coat. The turning point in the modeling came with the advent of freeze fracture techniques . These were later found to be proteins. The purpose of this presentation will be to show how membranes are studied by the cell biologist. First, we will look at basic unit membrane architecture .
All membranes contain proteins and lipid.
However, the proportion of each varies depending on the membrane. A electron micrograph of myelin is to the right. As we said above, membrane architecture is that of a lipid bilayer . The lipids are amphipathic in that they have hydrophilic polar heads pointing out and the hydrophobic portion forming the core. These figures are taken from your text, Figure 10-1, page 477.