Fort Rucker. Fort Rucker is a U.S. Army post located mostly in Dale County, Alabama, United States. It was named for a Civil War officer, Confederate General Edmund Rucker.
The reason that the cell membrane is considered to be 'semi-permeable' is because there are certain materials that can pass through the cell membrane (e.g. hydrocarbons and oxygen cross through the cell membrane as they can be dissolved into the lipid layer-other examples include small polar molecules.he basic structure of the cell membrane consists of layers. The cell membrane is a phospholid bi-layer. It is made up of proteins and lipids (also known as the phospholipid).
Plasma Membrane. All living cells, prokaryotic and eukaryotic, have a plasma membrane that encloses their contents and serves as a semi-porous barrier to the outside environment. The membrane acts as a boundary, holding the cell constituents together and keeping other substances from entering.The plasma membrane is permeable to specific molecules, however, and allows nutrients and other essential elements to enter the cell and waste materials to leave the cell.he membrane acts as a boundary, holding the cell constituents together and keeping other substances from entering. The plasma membrane is permeable to specific molecules, however, and allows nutrients and other essential elements to enter the cell and waste materials to leave the cell.