Structure and Transport. Chemical components and Examples Lipids such as Phospholipids, e.g., phosphotidylserine, and Steroids, e.g., cholesterol. The hydrophilic head groups of phospholipids form the outside of the membrane associate with water by hydrogen bonding. The membrane must be fluid to function. Fluid means that all chemical components of the membrane move past one another within the membrane.
Phospholipids undergo three types of motion.
Proteins also move laterally in the lipid bilayer. X-ray crystallography reveals a single hydrophobic alpha helix in a newly discovered integral membrane protein. A solution of high ionic strength. A chelating agent that removes divalent cations. A solution containing detergent.