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.
Definition of chuck. 1  1 : a cut of beef that includes most of the neck, the parts about the shoulder blade, and those about the first three ribs â see beef illustration. 2  2 chiefly Western US : food. 3  3 : an attachment for holding a workpiece or tool in a machine (such as a drill or lathe)