Prokaryotes 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.
3. countable noun. A wedge is an object with one pointed edge and one thick edge, which you put under a door to keep it firmly in position. 4. countable noun. A wedge is a piece of metal with a pointed edge which is used for splitting a material such as stone or wood, by being hammered into a crack in the material.
The wedge is the active twin of the inclined plane and one of the six classical simple machines. Unlike an inclined plane, which is stationary, a wedge does useful work by moving. A wedge is made up of two inclined planes. These planes meet and form a sharp edge. For a wedge, the effort (force) is applied to the vertical (height) of the wedge. To separate portions of an object (chisel)