To become more involved with the Gardens, many plant enthusiasts join the Friends of the Boerner Botanical Gardens for the opportunity to support and learn more about horticulture. Boerner Botanical Gardens. 9400 Boerner Drive, Hales Corners, WI 53130. (414) 525-5600.
The lipid bilayer is a thin polar membrane made of two layers of lipid molecules.These membranes are flat sheets that form a continuous barrier around all cells.The cell membranes of almost all living organisms and many viruses are made of a lipid bilayer, as are the membranes surrounding the cell nucleus and other sub-cellular structures.rokaryotes have only one lipid bilayer-the cell membrane (also known as the plasma membrane). Many prokaryotes also have a cell wall, but the cell wall is composed of proteins or long chain carbohydrates, not lipids.
Figure 1 summarizes the permeability properties of pure lipid bilayers. Lipid-soluble molecules can readily pass through a lipid bilayer. Examples include gas molecules such as oxygen (O 2) and carbon dioxide (CO 2), steroid molecules, and fat-soluble vitamins (A, D, E, and K). Surprisingly, some small polar molecules are capable of permeating the lipid bilayer without the aid of a membrane transport protein.