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.
Wedges are the highest-lofted clubs in a set of golf clubs, designed for short approach shots (for most golfers, 120 yards and in), strokes played out of sand, chip shots and pitch shots, and generally any shot for which the golfer wants the ball to ascend and descend sharply.