Historical Examples. 1  It will be seen that the valves v on the other side of the annular chamber are closed. 2  The angle of the anterior chamber is a true angle and not an annular sinus. 3  Johnston suggests that the reference is to an annular eclipse which he finds occurred on August 14, at about 8Â¼ h. in the morning.
Cellular nutrients come in many forms, including sugars and fats. In order to provide a cell with energy, these molecules have to pass across the cell membrane, which functions as a barrier â but not an impassable one.
The cell membrane (also known as the plasma membrane or cytoplasmic membrane) is a biological membrane that separates the interior of all cells from the outside environment. The cell membrane is selectively permeable to ions and organic molecules and controls the movement of substances in and out of cells. The basic function of the cell membrane is to protect the cell from its surroundings. It consists of the phospholipid bilayer with embedded proteins.