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.
Main article: Wedge (golf) Wedges are a sub-class of irons with greater loft than the numbered irons (generally starting at 47Â°-48Â° of loft, above the 9-iron's 44Â°-45Â°), and other features such as high-mass club heads and wide soles that allow for easier use in tricky lies.